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BIOLOGY (1417 journals)            First | 1 2 3 4 5 6 7 8 | Last

Showing 1201 - 1400 of 1720 Journals sorted alphabetically
Reports in Parasitology     Open Access   (Followers: 2)
Reports on Mathematical Physics     Full-text available via subscription  
Reports on Progress in Physics     Full-text available via subscription   (Followers: 3)
Reproductive Biology Insights     Open Access   (Followers: 1)
Reproductive Biomedicine & Society Online     Open Access  
Reproductive Toxicology     Hybrid Journal   (Followers: 14)
Research & Reviews : Journal of Computational Biology     Full-text available via subscription   (Followers: 2)
Research & Reviews : Journal of Ecology     Full-text available via subscription   (Followers: 1)
Research and Reports in Biodiversity Studies     Open Access  
Research and Reports in Biology     Open Access  
Research in Engineering Design     Hybrid Journal   (Followers: 10)
Research Journal of Parasitology     Open Access   (Followers: 3)
Research Journal of Seed Science     Open Access   (Followers: 4)
Research Journal of Soil Biology     Open Access   (Followers: 2)
Research Journal of Toxins     Open Access  
Resources     Open Access  
Retrovirology     Open Access   (Followers: 1)
Reviews in Fish Biology and Fisheries     Hybrid Journal   (Followers: 30)
Reviews of Modern Physics     Full-text available via subscription   (Followers: 18)
Revista Argentina de Antropología Biológica     Open Access  
Revista Brasileira de Biociencias     Open Access  
Revista Brasileira de Biologia     Open Access  
Revista Brasileira de Fisiologia Vegetal     Open Access  
Revista CENIC. Ciencias Biológicas     Open Access  
Revista Ceres     Open Access  
Revista Ciencias Marinas y Costeras     Open Access  
Revista Cubana de Investigaciones Biomédicas     Open Access   (Followers: 1)
Revista de Biología Tropical     Open Access   (Followers: 2)
Revista de Ciencia y Tecnología     Open Access  
Revista de Ciências Agroambientais     Open Access  
Revista de Educación en Biología     Open Access  
Revista de la Ciencia del Suelo y Nutricion Vegetal     Open Access  
Revista de Protección Vegetal     Open Access  
Revista Eletrônica de Biologia     Open Access  
Revista Eletrônica TECCEN     Open Access  
Revista Fitotecnia Mexicana     Open Access  
Revista Iberoamericana de las Ciencias Biológicas y Agropecuarias     Open Access  
Revista Iberoamericana de Micología     Full-text available via subscription  
Revista Latinoamericana de Bioética     Open Access  
Revista Mexicana de Biodiversidad     Open Access  
Revista Mexicana de Micologí­a     Open Access  
Revista Peruana de Biología     Open Access  
Revue de primatologie     Open Access  
Revue d’ethnoécologie     Open Access   (Followers: 1)
Rhodora     Full-text available via subscription  
Rice     Open Access   (Followers: 5)
Rice Science     Open Access   (Followers: 3)
Risk Analysis     Hybrid Journal   (Followers: 33)
RNA     Hybrid Journal   (Followers: 9)
RNA & Disease     Open Access  
RNA Biology     Full-text available via subscription   (Followers: 3)
RURALS: Review of Undergraduate Research in Agricultural and Life Sciences     Open Access   (Followers: 1)
Russian Journal of Biological Invasions     Hybrid Journal   (Followers: 1)
Russian Journal of Developmental Biology     Hybrid Journal   (Followers: 2)
Russian Journal of Marine Biology     Hybrid Journal   (Followers: 2)
Russian Journal of Mathematical Physics     Hybrid Journal  
Russian Physics Journal     Hybrid Journal  
Rwanda Journal     Full-text available via subscription  
Saudi Journal of Biological Sciences     Open Access   (Followers: 2)
Scholars' Research Journal     Open Access  
Science and Engineering Ethics     Hybrid Journal   (Followers: 6)
Science China Life Sciences     Open Access  
Science Signaling     Full-text available via subscription   (Followers: 18)
Science Technology & Society     Hybrid Journal   (Followers: 4)
Scientific Journal of Biological Sciences     Open Access   (Followers: 1)
Scientific Reports     Open Access   (Followers: 30)
Scientific Research Journal     Open Access  
Scientifica     Open Access  
SCIMETR : International Journal of Science     Open Access  
Seed Science and Technology     Full-text available via subscription   (Followers: 3)
Selection     Full-text available via subscription  
Self/Nonself - Immune Recognition and Signaling     Full-text available via subscription   (Followers: 2)
Selforganizology     Open Access  
Semiconductor Science and Technology     Open Access  
Seminars in Cancer Biology     Hybrid Journal   (Followers: 3)
Seminars in Cell & Developmental Biology     Hybrid Journal   (Followers: 5)
Seminars in Hematology     Hybrid Journal   (Followers: 12)
Sensing and Bio-Sensing Research     Open Access  
Sensors     Open Access   (Followers: 12)
Sierra Leone Journal of Biomedical Research     Open Access  
Signal Transduction     Hybrid Journal  
Signal Transduction Insights     Open Access   (Followers: 2)
Simbiosis : Journal of Biological Sciences     Open Access  
SINET : Ethiopian Journal of Science     Open Access   (Followers: 7)
Single Molecules     Hybrid Journal  
Small     Hybrid Journal   (Followers: 10)
Small GTPases     Full-text available via subscription   (Followers: 1)
Social and Natural Sciences Journal     Open Access  
Sociobiology     Open Access  
Somatosensory and Motor Research     Hybrid Journal   (Followers: 2)
Source Code for Biology and Medicine     Open Access  
South African Journal of Enology and Viticulture     Open Access  
South African Journal of Science     Open Access   (Followers: 3)
South Asian Journal of Experimental Biology     Open Access  
South Australian Naturalist, The     Full-text available via subscription  
Spatial Vision     Hybrid Journal   (Followers: 2)
Standards in Genomic Sciences     Open Access  
Statistics in Biosciences     Hybrid Journal   (Followers: 3)
Stem Cell and Translational Investigation     Open Access   (Followers: 2)
Stem Cell Biology and Research     Open Access   (Followers: 6)
Stem Cell Discovery     Open Access   (Followers: 4)
Stem Cell Epigenetics     Open Access   (Followers: 3)
Stem Cell Reports     Open Access   (Followers: 9)
Stem Cell Research     Open Access   (Followers: 14)
Stem Cell Reviews and Reports     Hybrid Journal   (Followers: 6)
Stem Cells     Hybrid Journal   (Followers: 8)
Stem Cells and Cloning: Advances and Applications     Open Access   (Followers: 1)
Stem Cells International     Open Access  
Steroids     Hybrid Journal  
Studies in Mycology     Open Access  
Studies on Neotropical Fauna and Environment     Hybrid Journal   (Followers: 1)
Subterranean Biology     Open Access  
Sugar Tech     Hybrid Journal   (Followers: 2)
Summa Phytopathologica     Open Access  
Sunsari Technical College Journal     Open Access  
Surface Science Reports     Full-text available via subscription   (Followers: 15)
Sustainability : The Journal of Record     Hybrid Journal   (Followers: 6)
Sustentabilidade em Debate     Open Access  
Symbiosis     Hybrid Journal   (Followers: 1)
Synthesis Lectures on Biomedical Engineering     Full-text available via subscription  
Synthetic Biology     Full-text available via subscription  
Systematic Biology     Hybrid Journal   (Followers: 12)
Systematics and Biodiversity     Hybrid Journal   (Followers: 8)
Systems and Synthetic Biology     Hybrid Journal   (Followers: 10)
Systems Biology in Reproductive Medicine     Hybrid Journal  
Taprobanica : The Journal of Asian Biodiversity     Open Access  
Taxon     Full-text available via subscription   (Followers: 4)
Telomere and Telomerase     Open Access  
Terrestrial Arthropod Reviews     Hybrid Journal  
The Anatomical Record : Advances in Integrative Anatomy and Evolutionary Biology     Hybrid Journal   (Followers: 2)
The Botulinum J.     Hybrid Journal  
The Breast Journal     Hybrid Journal   (Followers: 5)
The Bryologist     Full-text available via subscription   (Followers: 8)
The Cerebellum     Hybrid Journal   (Followers: 1)
The Coleopterists Bulletin     Full-text available via subscription   (Followers: 2)
The Condor     Full-text available via subscription   (Followers: 28)
The Enzymes     Full-text available via subscription   (Followers: 1)
The FASEB Journal     Full-text available via subscription   (Followers: 19)
The Herpetological Journal     Full-text available via subscription   (Followers: 5)
The International Journal of Advanced Manufacturing Technology     Hybrid Journal   (Followers: 4)
The Journal of Technology Transfer     Hybrid Journal   (Followers: 7)
The Knee     Hybrid Journal   (Followers: 14)
The Lichenologist     Hybrid Journal   (Followers: 5)
The Nucleus     Hybrid Journal   (Followers: 1)
The Physics of Metals and Metallography     Hybrid Journal   (Followers: 18)
The Plant Cell     Full-text available via subscription   (Followers: 24)
The Protein Journal     Hybrid Journal   (Followers: 12)
Theoretical Biology and Medical Modelling     Open Access   (Followers: 1)
Theoretical Population Biology     Hybrid Journal   (Followers: 8)
Tissue and Cell     Hybrid Journal   (Followers: 2)
Tissue Engineering and Regenerative Medicine     Hybrid Journal   (Followers: 8)
Tissue Engineering Part A     Hybrid Journal   (Followers: 9)
Tissue Engineering Part B: Reviews     Hybrid Journal   (Followers: 7)
Tissue Engineering Part C: Methods     Hybrid Journal   (Followers: 7)
Toxicology in Vitro     Hybrid Journal   (Followers: 12)
Traffic     Hybrid Journal   (Followers: 6)
Transactions of the Royal Society of South Australia     Hybrid Journal  
Transcription     Full-text available via subscription   (Followers: 2)
Transgenic Research     Hybrid Journal   (Followers: 3)
Translational Psychiatry     Open Access   (Followers: 9)
Transportation Planning and Technology     Hybrid Journal   (Followers: 8)
Tree Genetics & Genomes     Hybrid Journal   (Followers: 2)
Tree-Ring Research     Full-text available via subscription  
Trees     Hybrid Journal   (Followers: 5)
Trends in Bacteriology     Open Access   (Followers: 1)
Trends in Bioinformatics     Open Access   (Followers: 20)
Trends in Biotechnology     Full-text available via subscription   (Followers: 103)
Trends in Cell Biology     Full-text available via subscription   (Followers: 34)
Trends in Evolutionary Biology     Open Access   (Followers: 13)
Trends in Microbiology     Full-text available via subscription   (Followers: 28)
Trends in Molecular Sciences     Open Access   (Followers: 5)
Trends in Parasitology     Full-text available via subscription   (Followers: 7)
Trends in Plant Science     Full-text available via subscription   (Followers: 24)
Trends in Vector Research and Parasitology     Open Access  
Tropical Freshwater Biology     Full-text available via subscription  
Tumor Biology     Hybrid Journal   (Followers: 4)
Tumor Microenvironment and Therapy     Open Access  
Tunnelling and Underground Space Technology     Hybrid Journal   (Followers: 6)
Turkish Journal of Agricultural and Natural Science     Open Access  
Turkish Journal of Biology     Open Access  
Turtle and Tortoise Newsletter     Full-text available via subscription   (Followers: 1)
Ultrasound in Medicine & Biology     Full-text available via subscription   (Followers: 7)
Uniciencia     Open Access  
Universal Journal of Biomedical Engineering     Open Access  
Unnes Journal of Biology Education     Open Access  
Vakuum in Forschung und Praxis     Hybrid Journal   (Followers: 2)
Vascular Cell     Open Access  
Victorian Naturalist, The     Full-text available via subscription   (Followers: 3)
Virchows Archiv     Hybrid Journal  
Virologica Sinica     Hybrid Journal  
Virology Journal     Open Access   (Followers: 5)
Virulence     Full-text available via subscription  
Virus Evolution     Open Access  
Virus Genes     Hybrid Journal   (Followers: 1)
Virus Research     Hybrid Journal   (Followers: 1)
Visnyk of Dnipropetrovsk University. Biology, ecology     Open Access   (Followers: 2)
Visnyk of Dnipropetrovsk University. Biology, medicine     Open Access  
Walailak Journal of Science and Technology     Open Access  
Web Ecology     Open Access   (Followers: 6)
Weed Science     Full-text available via subscription   (Followers: 6)

  First | 1 2 3 4 5 6 7 8 | Last

Journal Cover Journal of Avian Biology
  [SJR: 1.201]   [H-I: 52]   [21 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0908-8857 - ISSN (Online) 1600-048X
   Published by John Wiley and Sons Homepage  [1597 journals]
  • Kind to kin: weak interference competition among white stork (Ciconia
           ciconia) broodmates
    • Abstract: Altricial nestlings in structured families show a diverse array of behavioural mechanisms to compete for food, ranging from signalling scrambles to aggressive interference. Rates of filial infanticide are moderately high in white storks. It has been hypothesized that this unusual behaviour is an adaptive parental response to the absence of efficient mechanisms of brood reduction (aggression or direct physical interference) by nestlings. To test this latter assumption, we analyzed video recordings of 41 complete feeding episodes at 32 broods during the first half of the nestling period, when nestlings complete 90% of growth and chick mortality and size asymmetries are highest. Parents delivered food to all nestlings simultaneously by regurgitating on the nest floor. No direct (bill to bill) feeding was recorded. Senior nestlings were never observed to limit their junior nestlings from eating food, either by aggression or physical interference. Experimental feeding tests revealed that heavier nestlings handled prey items more efficiently and ate food at a higher speed. The high degree of tolerance shown by senior nestlings is unusual among birds with similar ecological and phylogenetic affinities, such as herons. Tolerance by seniors cannot be easily explained by absence of parental favouritism or proximate factors known to affect the occurrence of sibling aggression in other species (rate of food transfer, brood size, hatching asynchrony or length of nestling period). This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-27T10:40:27.152228-05:
      DOI: 10.1111/jav.00983
  • Determining fine‐scale migratory connectivity and habitat selection for
           a migratory songbird by using new GPS technology
    • Authors: K.C. Fraser; A. Shave, A. Savage, A. Ritchie, K. Bell, J. Siegrist, J.D. Ray, K. Applegate, M. Pearman
      Abstract: Migratory aerial insectivores are among the fastest declining avian group, but our understanding of these trends has been limited by poor knowledge of migratory connectivity and the identification of critical habitat across the vast distances they travel annually. Using new, archival GPS loggers, we tracked individual purple martins (Progne subis) from breeding colonies across North America to determine precise (2000 km) breeding sites, with some individuals sharing the same roosting trees. Despite vast tracts of contiguous forest in this region, birds occupied a much more limited habitat, with most (56%) roosts occurring on small habitat islands that were strongly associated with water. Only 17% of these roosts were in current protected areas. These data reflect a critical advance in our ability to remotely determine precise migratory connectivity and habitat selection across vast spatial scales, enhancing our understanding of population dynamics and enabling more effective conservation of species at risk. This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-27T09:55:20.965932-05:
      DOI: 10.1111/jav.01091
  • Variation in Nestling Body Condition and Wing Development Predict
           Cause‐specific Mortality in Fledgling Dickcissels
    • Authors: Todd M. Jones; Michael P. Ward, Thomas J. Benson, Jeffrey D. Brawn
      Abstract: Phenotypic traits developed in one life‐history stage can carryover and affect survival in subsequent stages. For songbirds, carryover effects from the pre‐ to post‐fledging period may be crucial for survival but are poorly understood. We assessed whether juvenile body condition and wing development at fledging influenced survival during the post‐fledging period in the Dickcissel (Spiza americana). We found pre‐ to post‐fledging carryover effects on fledgling survival for both traits during the “early part”—first four days—of the post‐fledging period. Survival benefits of each trait depended on cause‐specific sources of mortality; individuals in better body condition were less likely to die from exposure to adverse environmental conditions, whereas those with more advanced wing development were less likely to be preyed upon. Fledglings with more advanced wing development were comparatively more active and mobile earlier in the post‐fledging period, suggesting they were better able to avoid predators. Our results provide some of the first evidence linking development of juvenile phenotypic traits to survival against specific sources of post‐fledging mortality in songbirds. Further investigation into pre‐ to post‐fledging carryover effects may yield important insights into avian life‐history evolution. This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-27T09:50:20.969796-05:
      DOI: 10.1111/jav.01143
  • Winter territory prospecting is associated with life‐history stage but
           not activity in a passerine
    • Abstract: Finding a high quality territory is essential for many animals to reproduce successfully. Despite its importance for fitness, we know little about the process of territory prospecting in wild birds, and whether individual traits and behaviours, such as personality, co‐vary with territory prospecting. Here, we use long‐term data from a wild, insular house sparrow Passer domesticus population to test three hypotheses about territory fidelity and prospecting: (1) House sparrows show high territory fidelity between years and also during winter. (2) Individuals will prospect for a breeding territory during their first winter whereas older, more experienced individuals will keep a territory from previous years and will, therefore, show no or reduced winter territory prospecting. (3) More active behavioural types will prospect more than less active behavioural types. We use data from four winters from automatically, daily recorded nest‐box visits of 188 birds of known age. The number of nest‐boxes that each individual visited within each winter was used as a proxy of winter territory prospecting. We show that house sparrows visit multiple nest‐boxes during their first winter, whereas older individuals keep territories year‐round and, potentially because of this, indeed show reduced winter territory prospecting. Activity was not associated with the number of nest‐boxes visited. Further research is needed to investigate whether time of territory and mate acquisition differs among individuals and the possible effect on lifetime fitness. This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-21T05:11:38.62766-05:0
      DOI: 10.1111/jav.01055
  • Point of no return – absence of returning birds in the otherwise
           philopatric willow warbler (Phylloscopus trochilus)
    • Abstract: The return of individual birds to a specific area in successional years, i.e. philopatry, is a remarkable behavioural trait. Here we report on the remarkably reversed: the complete absence of returning individuals of a migratory passerine with otherwise pronounced philopatry. At a high latitude study site in Abisko (68°32’N, 18°80’E) in northern Sweden none of the banded adult willow warblers (Phylloscopus trochilus) returned to breed 2011‐14. This is in stark contrast to all other reports in the literature and also to our two southern study sites (at 56°56’N, 18°10’E and at 58°94’N, 17°14’E) where 18‐38% of adults returned. We investigated this aberrant pattern found in Abisko by analysing three parameters known to influence philopatry; nest predation, breeding success and breeding density, and predicted that absence of philopatry should co‐occur with low breeding success, low breeding density and/or high nest predation. The results did not corroborate this, except that breeding density was lower at Abisko (49‐71 pairs/km2) than at the southern sites (106 pairs/km2, 101 pairs/km2). Instead, we suggest the hypothesis that the absence of philopatry is caused by an influx of southern, dispersal‐prone individuals deploying another breeding strategy and that this intra‐specific range expansion is enabled by milder climate and low population density. This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-21T05:00:44.154382-05:
      DOI: 10.1111/jav.00973
  • Pair complementarity influences reproductive output in the polymorphic
           black sparrowhawk (Accipiter melanoleucus)
    • Authors: Gareth Tate; Petra Sumasgutner, Ann Koeslag, Arjun Amar
      Abstract: How multiple morphs are maintained within populations of colour polymorphic bird species remains a challenging question in evolutionary ecology. In some systems, differential productivity or survival between morphs are thought to play a role. Here we examine key demographic parameters between the two discrete adult morphs that characterise the polymorphic black sparrowhawk Accipiter melanoleucus. Using long‐term breeding and survival data from a population on the Cape Peninsula, South Africa, we test for differences in reproductive performance between light and dark morphs, both in isolation and in combination with their partner morph and adult survival between morphs. We found that neither morph had a specific advantage in terms of productivity or survival. Despite this lack of difference between the individual morphs, we did however find that morph combination of adult pairs influenced productivity significantly, with mixed‐pairs producing more offspring per year than pairs consisting of the same morph. The body condition of the offspring showed the opposite relationship, with nestlings of mixed‐pairs having lower body condition than nestlings of like‐pairs. While our results suggest an advantage of mating with the opposite morph, there was no evidence for disassortative mating; instead breeding pair morph combinations were random with respect to the background frequencies of the two morphs. Higher productivity of mixed‐pairs may be the result of the complementary nature of care provided by the different morphs. We propose that differential foraging success between black sparrowhawk morphs under varying light conditions allows mixed‐pairs to expand their foraging niche. We conclude that emergent pair‐level properties may play an important role in promoting and maintaining polymorphism and may be important for other bird species which display bi‐parental care. This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-06T10:40:21.86018-05:0
      DOI: 10.1111/jav.01100
  • Early exposure to a bacterial endotoxin advances the onset of moult in the
           European starling
    • Authors: Simone Pirrello; Andrea Pilastro, Diego Rubolini, Jacopo G. Cecere, Andrea Romano, Alessandro Andreotti, Stefano Volponi, Nicola Saino, Matteo Griggio, Lorenzo Serra
      Abstract: In animals, events occurring early in life can have profound effects on subsequent life‐history events. Early developmental stresses often produce negative long‐lasting impacts, although positive effects of mild stressors have also been documented. Most studies of birds have investigated the effects of events occurring at early developmental stages on the timing of migration or reproduction, but little is known on the long‐term effects of these early events on moulting and plumage quality. We exposed European starling (Sturnus vulgaris) nestlings to an immune challenge to assess the effects of a developmental stress on the timing of the first (post‐juvenile) and second (post‐breeding) complete annual moult, the length of the flight feathers, and the length and colouration of ornamental throat feathers. The nestlings were transferred to indoor aviaries before fledgling and kept in captivity until the end of post‐breeding moult. Individuals treated with Escherichia coli lypopolysaccharide (LPS) started both moult cycles earlier compared to control siblings. Moult duration was unaffected by the immune challenge, but an advanced moult onset resulted in a longer moult duration. Moreover, female (but not male) throat feather colouration of LPS‐injected individuals showed a reduced UV chroma. We argue that an early activation of the immune system caused by LPS may allow nestlings to better cope with post‐fledging stresses and lead to an earlier moult onset. The effect of early LPS exposure was remarkably persistent, as it was still visible more than one year after the treatment, and highlighted the importance of early developmental stresses in shaping subsequent major life‐history traits, including the timing of moult in birds. This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-06T10:36:43.164233-05:
      DOI: 10.1111/jav.01017
  • Trade‐offs between reproduction and self‐maintenance (immune function
           and body mass) in a small seabird, the little auk
    • Abstract: Breeding season is the most energetically and physiologically demanding phase in the avian annual cycle, challenging adults' physiology and survival. However, the timing and extent that self‐maintenance of breeding adults is compromised during the breeding season is poorly understood. We investigated the trade‐off between reproduction and self‐maintenance in relation to breeding phase (prelaying, incubation, chick rearing) and sex in a small Arctic seabird, the little auk (Alle alle). To measure a bird's allocation of time for self‐maintenance, we examined size‐adjusted body mass and immunocompetence expressed by bacteria (Escherichia coli) killing capacity (BKC) of blood plasma, heterophils/lymphocyte ratio (H/L) and their numbers of particular leucocytes per 10 000 red blood cells (RBC). We found that size‐adjusted body mass decreased as the breeding season progressed. BKC, number of heterophils and H/L values were all was significantly higher at prelaying when compared to all other phases. Interestingly, we found that heavier individuals had higher BKC and number heterophils at the prelaying and chick rearing phases than light individuals. There were no differences by sex in any studied variables. Our results indicate that immunocompetence and body mass of breeding adults decreases over the course of breeding season. The efficiency of the immune system appears to be dependent on the bird's body reserves. Our results suggest that little auks allocation of resources into reproduction negatively affects their self‐maintenance. This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-06T10:36:41.994403-05:
      DOI: 10.1111/jav.01000
  • Non‐moulted primary coverts correlate with rapid primary moulting
    • Authors: Yosef Kiat; Ido Izhaki
      Abstract: Time constraint is a main factor which affects the moult strategies in passerines, mainly during the first year of life. The variability of moult strategies between species is associated with the extent of the moult. In the first year of life, the extent of the moult is highly variable between species and individuals. In most passerine species, juveniles only renew some of their feathers, but the factors that govern which feathers are renewed and which are retained have been largely overlooked. Here we examine the common pattern of non‐moulted primary coverts (PC) in passerines during the first‐year moult cycle (post‐juvenile and first‐year pre‐breeding moults). On the interspecific level we found that among 63 species of passerines, PCs are the least commonly moulted feather tract. For five species (Hirundo rustica, Pycnonotus xanthopygos, Prinia gracilis, Acrocephalus stentoreus and Passer moabiticus) which perform a complete post‐juvenile moult, we found that the PC moult occurs over a longer period than greater coverts (GCs) and is sequential (non‐simultaneous). At the intraspecific level, we found that the main difference between a partial and complete moult in Prinia gracilis is the moulting or non‐moulting of the PCs. We also demonstrate that for Prinia gracilis (1) juveniles which do not moult their PCs, moult their primaries at a higher speed than those which moult their PCs and (2) area / mass ratio of PCs is lower than of GCs. These two findings may explain why many passerines skip PC renewal during the first year of life. Because the PC moult lasts a long time, forgoing this moult enables long term resource savings that allow for dealing with time constraints. Our results highlight the adaptive advantages of non‐moulted PCs in cases of time constraints. This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-06T10:30:22.850961-05:
      DOI: 10.1111/jav.00939
  • Decoding colouration of begging traits by the experimental addition of the
           appetite enhancer cyproheptadine hydrochloride in magpie (Pica pica)
    • Abstract: The colouration of some traits in nestlings of altricial birds may influence parental food allocation as it may reflect physical condition or hunger. There is increasing evidence of the relationship between colouration of begging traits and nestling performance. However, evidence of the influence of hunger level on nestling colouration is scarce, mainly because of difficulty of distinguishing between the effects of physical condition and hunger levels. Here, we used the appetite stimulant cyproheptadine hydrochloride to increase the sensation of hunger of magpie (Pica pica) nestlings for eight days and assessed the effect on the colouration of rictal flanges, mouth and body skin. We found that nestlings administered with cyproheptadine had flanges more conspicuous (chromatic visual contrast), more UV coloured and less yellow coloured than their control nestmates. Conversely, mouths of experimental nestlings were more yellow coloured and less UV coloured than controls. Our pharmacological experiment affected the strength of the relationship between body mass and some colour components of body skin (chromatic and achromatic visual contrasts, UV–chroma and Yellow–chroma) and of rictal flanges (chromatic visual contrasts, UV–chroma and yellow–chroma), but not for mouth colouration. These results taken together suggest that the effect of the cyproheptadine on nestling colourations is probably mediated by an increase in hunger levels of nestlings for rictal flanges and body skin colourations, and by an increase in physical condition in the case of mouth coloration. This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-06T10:10:22.82591-05:0
      DOI: 10.1111/jav.00641
  • Post‐fledging family space use in blue and great tit: similarities and
           species‐specific behaviours
    • Authors: Thijs Overveld; Michalis Vardakis, Lisa Arvidsson, Kristine Stolk, Frank Adriaensen, Erik Matthysen
      Abstract: In birds, parental escorting of dependent young to feeding areas outside the breeding territory is a commonly observed, yet poorly documented phenomenon. Using radio‐tracking, we provide a detailed description of the post‐fledging movements of 12 blue tit families (Cyanistes caeruleus) and compare these observations with a much larger dataset of the closely related great tit (Parus major) collected over several years in the same study area. The proportion of families making excursions outside woodlots was similar in both species (± 50%), but the spatial extent of these movements tended to be larger in blue tits (mean ± SE: 1100m ± 265, range: 643‐2374, n = 6) as compared to great tits (mean ± SE: 666 m ± 42, range: 245‐1898, n = 64). Blue tit families foraged significantly more in oak habitat within woodlots, independently of excursion behaviour, whereas great tits undertaking excursions shifted their range use towards more variable habitat outside woodlots. The observed excursions of blue tits appeared multiple‐day or permanent shifts of the family range, and not daily excursions as most frequently observed in great tits. Although family movements in both species may be largely driven by common underlying factors, our results also points toward species‐specific difference in spatial behaviour which may be linked with foraging specializations and post‐fledging territory fidelity. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-20T08:50:32.035971-05:
      DOI: 10.1111/jav.00999
  • Long‐term population dynamics reveal that survival and recruitment of
           tropical boobies improve after a hurricane
    • Abstract: Variability in population numbers is a central issue in evolutionary ecology and also in biodiversity conservation. However, for most seabirds this information is lacking and tropical populations are virtually unstudied. Long‐term studies are warranted because world's seabird populations exhibit an overall declining trend since 1950. Using data spanning 23 years, we investigated how adult survival, local recruitment, and their relative contributions to population growth (λ) vary over time in the blue‐footed booby (Sula nebouxii), a long‐lived locally foraging seabird that breeds in tropical waters. In addition, we investigated whether booby demographic rates exhibit the same declining trend observed in other seabirds, whether these rates are impacted by hurricanes, and whether these potential impacts differ between sexes. Our analysis of 4608 capture‐recapture histories revealed that survival and recruitment were nearly equal between males and females, exhibited a declining trend over the last 23 years, and in both sexes, these vital rates improved after a hurricane. The declining trend in recruitment was slightly more attenuated in males. These results add to the current evidence for an overall declining trend in world's seabird populations and extend its confirmation to the warm eastern tropical Pacific. Moreover, they provide the first evidence that hurricanes may favor natural populations. As a result of the declining trend and variation in survival and recruitment, λ exhibited a slight decline and substantial variation over the 23 years. However, most λ values were equal to or higher than 1, and the long‐term average indicates population increase. The ability of blue‐footed boobies to maintain a positive population balance despite of negative trends in their vital rates might result from canalization of adult survival (the vital rate that contributes most to λ and shows lower variation compared to recruitment) against environmental variability. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-15T08:45:46.653599-05:
      DOI: 10.1111/jav.01133
  • Stable isotopes reveal differences in diet among reed bunting subspecies
           that vary in bill size
    • Abstract: Reed bunting (Emberiza schoeniclus) subspecies vary considerably in bill size and shape and seem to be at an early stage of speciation, in which bill might be indirectly causing reproductive isolation. Hence, we evaluated whether bill size, as well as age and sex, are associated with foraging niche in three West European subspecies of reed bunting: the thin‐billed schoeniclus, the intermediate‐billed lusitanica and the thick‐billed witherbyi. Blood sampling was undertaken at three sites in southwest Europe during the winter (when these subspecies co‐occur), and stable isotope analyses (carbon and nitrogen) were performed to assess their foraging niches. Stable isotope analyses of potential food items confirmed uniform baseline isotopic composition among sites. schoeniclus showed a significantly broader isotopic niche than lusitanica and witherbyi, which seemed otherwise similar despite the fact that witherbyi is more divergent in bill traits. Stable isotope ratios were consistent with the latter two subspecies feeding on C3‐plant‐feeding insects, whereas schoeniclus diet also included C4 plant material. Despite its lower sexual dimorphism, sex and age differences were found only in schoeniclus, but these differences vary between locations in a complex manner. Our results suggest that bill size and shape differentiated between northern, migratory and southern, resident subspecies as a consequence of natural selection through competition during the winter, which is now reflected in isotopic niche divergence between subspecies. The potential roles of sexual selection, reed thickness and summer temperature on the difference in bill size (and greater sexual dimorphism) between lusitanica and witherbyi are discussed. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-15T08:40:38.535886-05:
      DOI: 10.1111/jav.01069
    • Abstract: We describe a method and device (< 1.2 g) for recording, processing and storing data about activity and location of individuals of free‐living songbirds throughout the annual cycle. Activity level was determined every five minutes from five 100 ms samples of accelerometer data with 5 s between the sampling events. Activity levels were stored on an hourly basis throughout the annual cycle, allowing periods of resting/sleep, continuous flight and intermediate activity (foraging, breeding) to be distinguished. Measurements from a light sensor were stored from preprogrammed key stationary periods during the year to provide control information about geographic location. Successful results, including annual actogram, were obtained for a red‐backed shrike Lanius collurio carrying out its annual loop migration between northern Europe and southern Africa. The shrike completed its annual migration by performing >66 (max. 73) nocturnal migratory flights (29 flights in autumn and >37, max. 44, in spring) adding up to a total of >434 (max. 495) flight hours. Migratory flights lasted on average 6.6 h with maximum 15.9 h. These flights were aggregated into eight travel episodes (periods of 4‐11 nights when flights took place on the majority of nights). Daytime resting levels were much higher during the winter period compared to breeding and final part of spring migration. Daytime resting showed peaks during days between successive nocturnal flights across Sahara, continental Africa and the Arabian Peninsula, indicating that the bird was mostly sleeping between these long migratory flights. Annual activity and flight data for free‐living songbirds will open up many new research possibilities. Main topics that can be addressed are e.g. migratory flight performance (total flight investment, numbers and characteristics of flights), timing of stationary periods, activity patterns (resting/sleep, activity level) in different phases of the annual cycle and variability in the annual activity patterns between and within individuals. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-15T08:25:33.538484-05:
      DOI: 10.1111/jav.01068
  • Habitat selection by postbreeding female diving ducks: influence of
           habitat attributes and conspecifics
    • Authors: Jane E. Austin; Shawn T. O'Neil, Jeffrey M. Warren
      Abstract: Habitat selection studies of postbreeding waterfowl have rarely focused on within‐wetland attributes such as water depth, escape cover, and food availability. Flightless waterfowl must balance habitat selection between avoiding predation risks and feeding. Reproductively successful female ducks face the greatest challenges because they begin the definitive prebasic molt at or near the end of brood rearing, when their body condition is at a low point. We assessed the relative importance of habitat attributes and group effects in habitat selection by postbreeding female lesser scaup (Aythya affinis) on a 2,332‐ha montane wetland complex during the peak flightless period (August) over seven years. Hypothesis‐based habitat attributes included percent open water, open water:emergent edge density, water depth, percent flooded bare substrate, fetch (distance wind can travel unobstructed), group size, and several interactions representing functional responses to interannual variation in water levels. Surveys of uniquely marked females were conducted within randomly ordered survey blocks. We fitted two‐part generalized linear mixed‐effects models to counts of marked females within survey blocks, which allowed us to relate habitat attributes to relative probability of occurrence and, given the presence of a marked female, abundance of marked individuals. Postbreeding female scaup selected areas with water depths > 40 cm, large open areas, and intermediate edge densities but showed no relation to flooded bare substrate, suggesting their habitat preferences were more influenced by avoiding predation risks and disturbances than in meeting foraging needs. Grouping behavior by postbreeding scaup suggests habitat selection is influenced in part by behavioral components and/or social information, conferring energetic and survival benefits (predation and disturbance risks) but potentially also contributing to competition for food resources. This study demonstrates the importance of incorporating group effects and interannual variability in habitat conditions when investigating habitat selection, particularly for seasons when waterfowl are aggregated. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-15T08:15:29.118415-05:
      DOI: 10.1111/jav.01063
  • Tracking the Stejneger's stonechat Saxicola stejnegeri along the East
           Asian–Australian Flyway from Japan via China to Southeast Asia
    • Authors: Yuichi Yamaura; Heiko Schmaljohann, Simeon Lisovski, Masayuki Senzaki, Kazuhiro Kawamura, Yuzo Fujimaki, Futoshi Nakamura
      Abstract: The East Asian–Australian Flyway spans from North Asia to Australia and is the world's richest birds’ flyway because it involves >40% of global migratory bird species. However, information is lacking on individual migratory routes and non‐breeding grounds for small land birds using this flyway. Here, we present the first migration tracks of the songbird Stejneger's stonechat (Saxicola stejnegeri) from this part of the world using light‐level geolocators. This species depends on grasslands during the entire annual cycle and was captured and equipped with tracking devices in Hokkaido, northern Japan. All individuals traveled through southern Primorye or eastern Heilongjiang (Russia/China) before flying southward via central China toward their major non‐breeding grounds in Southeast Asia (China, Laos, Cambodia, Thailand, and Vietnam). Individual stonechats spent 42–70 days en route during their autumn migration. Both the major non‐breeding grounds and the stopover sites are likely to pose challenges to the persistence of this species, because these habitats are currently degraded and will likely be lost in the near future due to intensified agriculture and the establishment of permanent croplands. Moreover, the areas used by Stejneger's stonechat during migration largely overlapped with illegal trapping areas in northeastern China. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-15T08:10:23.844189-05:
      DOI: 10.1111/jav.01054
  • Testosterone levels in relation to size and UV reflectance of achromatic
           plumage traits of female pied flycatchers
    • Abstract: In a substantial number of species, females show some development of secondary sexual characters. These traits can function as signals of individual phenotypic or genetic qualities and status to conspecifics. Individuals may benefit potentially from expressing signals or badges of status if they are reliable and honest signals of individual quality. In many species, badge sizes have been shown to correlate with dominance rank, which may be mediated by testosterone (T) levels. Here, we explored geographic variation in the size and properties of the white wing patch of female pied flycatchers Ficedula hypoleuca and its relation to circulating T levels in three populations (two southern populations in central Spain and a northern population in Finland). Furthermore, we aimed at detecting if the size of the white wing patch and its ultraviolet (UV) reflectance indicate individual quality. We found that females in Spain had larger, brighter and more UV reflecting wing patches than those in Finland. Females with higher UV reflectance and larger primary white patches bred earlier. Younger females and females with larger primary white wing patches showed higher T levels. In contrast, higher values of UV reflectance in feathers from these patches were associated with low T levels. Despite genetic differentiation and differences in trait expression between populations, female pied flycatchers from different populations may converge and use the size of white wing patches to signal their T levels and thereby their social dominance. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-15T07:35:40.689387-05:
      DOI: 10.1111/jav.01032
  • An empirical comparison of models for the phenology of bird migration
    • Abstract: Bird migration phenology shows strong responses to climate change. Studies of trends and patterns in phenology are typically based on annual summarizing metrics, such as means and quantiles calculated from raw daily count data. However, with irregularly sampled data and large day‐to‐day variation, such metrics can be biased and noisy, and may be analysed using phenological functions fitted to the data. Here we use count data of migration passage from a Finnish bird observatory to compare different models for the phenological distributions of spring migration (27 species) and autumn migration (57 species). We assess parsimony and goodness‐of‐fit in a set of models, with phenological functions of different complexity, optionally with covariates accounting for day‐to‐day variability. The covariates describe migration intensities of related species or relative migration intensities the previous day (autocovariates). We found that parametric models are often preferred over the more flexible generalized additive models with constrained degrees of freedom. Models corresponding to a mixture of two distinct passing populations were frequently preferred over simpler ones, but usually no more complex models are needed. Slightly more complex models were favoured in spring compared to autumn. Related species’ migration activity effectively improves the model by accounting for the large day‐to‐day variation. Autocovariates were usually not that relevant, implying that autocorrelation is generally not a major concern if phenology is modelled properly. We suggest that parametric models are relatively good for studying single‐population migration phenology, or a mix of two groups with distinct phenologies, especially if daily variation in migration intensity can be controlled for. Generalized additive models may be useful when the migrating population composition is unknown. Despite these guidelines, choosing an appropriate model involves case‐by‐case assessment or the biological relevance and rationale for modelling phenology. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-15T07:25:24.685225-05:
      DOI: 10.1111/jav.00994
  • Is offspring dispersal related to male mating status? An experiment with
           the facultatively polygynous spotless starling
    • Abstract: Patterns of natal dispersal are generally sex‐biased in vertebrates, i.e., female‐biased in birds and male‐biased in mammals. Interphyletic comparisons in mammals suggest that male‐biased dispersal occurs in polygynous and promiscuous species where local mate competition among males exceeds local resource competition among females. However, few studies have analysed sex‐biased patterns of dispersal at the individual level, and facultatively polygynous species might offer this opportunity. In the spotless starling, polygynous males exhibit their mating status during courtship carrying higher amounts of green plants to nests than monogamous males. We experimentally incorporated green plants to nests during four years to analyse long‐term consequences on breeding success and offspring recruitment rates. We unexpectedly found that experimental sons recruited farther than experimental daughters, while control daughters recruited farther than control sons. A similar pattern was found using observational information from eight years. We discuss this result in the context of local competition hypothesis and speculate that sons dispersed farther from nests controlled by polygynous males to avoid competition with relatives. The amount of green plants in nests affects female perception of male attractiveness and degree of polygyny, although little is known about proximate mechanisms linking this process with the offspring dispersal behaviour. Our results support the idea that male‐biased dispersal is related to polygyny in a facultatively polygynous bird. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-15T07:15:43.890998-05:
      DOI: 10.1111/jav.00974
  • Song rate as a signal of male aggressiveness during territorial contests
           in the wood warbler
    • Abstract: Aggressive signaling is an important component in animal communication, as it provides an efficient mechanism for settling conflicts over resources between competitors. In songbirds, a number of singing behaviors have been proposed to be aggressive signals used in territory defense, including song rate. Although aggressive signaling in songbirds has received considerable research attention, adequate evidence for most putative aggressive signals is not available. In this study, we experimentally investigated whether the song rate of male wood warblers (Phylloscopus sibilatrix) is a signal of their aggressive intent in male‐male interactions. We found that males responded differentially to simulated territorial intrusions depending on the song rate of an intruder. Moreover, males that continued to sing during territorial contests increased their song rates, and this behavior predicted the strength of aggressive escalation by the signaler. These results suggest that song rate is an aggressive signal during male‐male interactions in the wood warbler. We also found high intra‐individual repeatability in the strength of aggressive response to simulated intrusions, likely reflecting differences in personality (aggressiveness) or quality of male wood warblers. We conclude that changes in singing rate may be an efficient mechanism of signaling immediate shifts in motivation of signalers during territorial contests, especially in species that lack large repertoires or have simple songs. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-14T10:50:52.817753-05:
      DOI: 10.1111/jav.00969
  • Bias in ring‐recovery studies: causes of mortality of little owls
           (Athene noctua) and implications for population assessment
    • Abstract: Recoveries of marked animals hold long‐term, large‐scale information on survival and causes of mortality, but are prone to bias towards dead recoveries and casualties in the range of presence of potential finders. Thus, accounting for circumstance‐related recovery probabilities is crucial in statistical approaches. For the little owl, a species of conservation concern in Central Europe, raw ring recoveries suggested a strong human‐related impact on survival. We analysed the proportions of the main causes of death using a large sample of radio‐tracked birds as a reference. We compared ring recoveries in Southern Germany collected 1950 – 2012 (n = 465 dead recoveries of 2007 recoveries of 30623 ringed birds) with data from a radio‐tracking study in the same region 2009 – 2012 (n = 177 dead recoveries of 377 tagged individuals). Two assumptions of multi‐state ring recovery modelling were unrealistic. First, not all dispatched rings remained available to potential finders. Instead, 34 % of tracked birds were displaced to sites where rings were irretrievable, resulting in biased estimates of recovery probability. Second, the proportions of irretrievable rings were disproportional, with 48 % in predated birds and 5 % in human‐induced mortality. Consequently, the sample of rings from which recoveries were drawn differed from the sample of dispatched rings. Accounting for these biases in a multi‐state model, we estimated the frequencies of main causes of mortality to 45 % for predation, 20 % for casualties due to traffic and at buildings and 34 % for all other causes. In radio‐tracked birds, predation was even more dominant (76%). Integrating mark‐recapture data and telemetry observations allowed detecting and quantifying so far unknown recovery bias and resulted in improved estimates of key population parameters. The demography of little owls likely depends mainly on predator‐prey relationships rather than on human‐induced deaths. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-14T10:35:52.21799-05:0
      DOI: 10.1111/jav.00947
  • Breeding latitude leads to different temporal but not spatial organization
           of the annual cycle in a long‐distance migrant
    • Abstract: The temporal and spatial organization of the annual cycle according to local conditions is of crucial importance for individuals’ fitness. Moreover, which sites and when particular sites are used can have profound consequences especially for migratory animals, because the two factors shape interactions within and between populations, as well as between animal and the environment. Here, we compare spatial and temporal patterns of two latitudinally separated breeding populations of a trans‐Equatorial passerine migrant, the Collared Flycatcher Ficedula albicollis, throughout the annual cycle. We found that migration routes and non‐breeding residency areas of the two populations largely overlapped. Due to climatic constraints, however, the onset of breeding in the northern population was approximately two weeks later than that of the southern population. We demonstrate that this temporal offset between the populations carries‐over from breeding to the entire annual cycle. The northern population was consistently later in timing of all subsequent annual events – autumn migration, non‐breeding residence period, spring migration and the following breeding. Such year‐round spatiotemporal patterns suggest that annual schedules are endogenously controlled with breeding latitude as the decisive element shaping the timing of annual events in our study populations. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-30T05:15:22.848436-05:
      DOI: 10.1111/jav.01002
  • Species delimitation of the White‐tailed Rubythroat Calliope pectoralis
           complex (Aves, Turdidae) using an integrative taxonomic approach
    • Abstract: Our knowledge of the systematics and taxonomy of Asian birds has improved much in the last two decades, and the number of recognised species has increased significantly as a result of in‐depth studies using an integrative taxonomic approach. The Sino‐Himalayan mountains harbor a high level of passerine diversity. Several allopatric or parapatric taxa that are currently treated as subspecies of polytypic species within that region are likely to deserve full species status, and thus their taxonomic status needs to be revisited. Based on analyses of multilocus data, vocalizations and morphology, we propose that the White‐tailed Rubythroat Calliope pectoralis should be treated as two species, the Himalayan Rubythroat C. pectoralis sensu stricto in the Tian Shan and Himalayan mountains, and the Chinese Rubythroat C. tschebaiewi in the mountains of southwestern and north‐central China. According to our dating analyses based on mitochondrial loci, these two species diverged approximately 2.2 million years ago. We further found that C. tschebaiewi was paraphyletic to C. pectoralis sensu stricto in nuclear data, which demonstrates a state of mitonuclear discordance that warrants further work. Our results suggest that geographic changes and glacial cycles in the Pleistocene may have caused allopatric divergence in the C. pectoralis complex. Our study stresses the importance of applying an integrative taxonomy approach to fully unravel the true avian diversity in the Sino‐Himalayan Mountains. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-30T05:10:48.889535-05:
      DOI: 10.1111/jav.01015
  • The relationship between female brooding and male nestling provisioning:
           does climate underlie geographic variation in sex roles'
    • Authors: Jongmin Yoon; Helen R. Sofaer, T. Scott Sillett, Scott A. Morrison, Cameron K. Ghalambor
      Abstract: Comparative studies of populations occupying different environments can provide insights into the ecological conditions affecting differences in parental strategies, including the relative contributions of males and females. Male and female parental strategies reflect the interplay between ecological conditions, the contributions of the social mate, and the needs of offspring. Climate is expected to underlie geographic variation in incubation and brooding behavior, and can thereby affect both the absolute and relative contributions of each sex to other aspects of parental care such as offspring provisioning. However, geographic variation in brooding behavior has received much less attention than variation in incubation attentiveness or provisioning rates. We compared parental behavior during the nestling period in populations of orange‐crowned warblers (Oreothlypis celata) near the northern (64°N) and southern (33°N) boundaries of the breeding range. In Alaska, we found that males were responsible for the majority of food delivery whereas the sexes contributed equally to provisioning in California. Higher male provisioning in Alaska appeared to facilitate a higher proportion of time females spent brooding the nestlings. Surprisingly, differences in brooding between populations could not be explained by variation in ambient temperature, which was similar between populations during the nestling period. While these results represent a single population contrast, they suggest additional hypotheses for the ecological correlates and evolutionary drivers of geographic variation in brooding behavior, and the factors that shape the contributions of each sex. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-30T05:10:47.741459-05:
      DOI: 10.1111/jav.00890
  • Unpredictable Perturbation Reduces Breeding Propensity Regardless Of
           Pre‐Laying Reproductive Readiness In A Partial Capital Breeder
    • Abstract: Theoretically, individuals of migratory species should optimize reproductive investment based on a combination of timing of and body condition at arrival on the breeding grounds. A minimum threshold body mass is required to initiate reproduction, and the timing of reaching this threshold is critical because of the trade‐off between delaying breeding to gain in condition against the declining value of offspring with later reproductive timing. Long‐lived species have the flexibility within their life history to skip reproduction in a given year if they are unable to achieve this theoretical mass threshold. Although the decision to breed or not is an important parameter influencing population dynamics, the mechanisms underlying this decision are poorly understood. Here, we mimicked an unpredictable environmental perturbation that induced a reduction in body mass of Arctic pre‐breeding (before the laying period) female common eiders (Somateria mollissima; a long‐lived migratory seaduck) while controlling for individual variation in the pre‐laying physiological reproductive readiness via vitellogenin (VTG) ‐ a yolk‐targeted lipoprotein. Our aim was to causally determine the interaction between body condition and pre‐laying reproductive readiness (VTG) on breeding propensity by experimentally reducing body mass in treatment females. We first demonstrated that arrival body condition was a key driver of breeding propensity. Secondly, we found treatment and VTG levels interacted to influence breeding propensity, indicating that our experimental manipulation, mimicking an unpredictable food shortage, reduced breeding propensity, regardless of the degree of pre‐laying physiological reproductive readiness (i.e., timing of ovarian follicles recruitment). Our experiment demonstrates that momentary environmental perturbations during the pre‐breeding period can strongly affect the decision to breed, a key parameter driving population dynamics. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-30T05:10:46.669786-05:
      DOI: 10.1111/jav.00824
  • Low levels of hybridization across two contact zones among three species
           of woodpeckers (Sphyrapicus sapsuckers)
    • Authors: Sampath S. Seneviratne; Peter Davidson, Kathy Martin, Darren E. Irwin
      Abstract: Three species of closely related woodpeckers (sapsuckers; Sphyrapicus) hybridize where they come into contact, presenting a rare ‘λ‐shape’ meeting of hybrid zones. Two of the three arms of this hybrid zone are located on either side of the Interior Plateau of British Columbia, Canada bordering the foothills of the Coast Mountains and the Rocky Mountains. The third arm is located in the eastern foothills of the Rocky Mountains. The zones of hybridization present high variability of phenotypes and alleles in relatively small areas and provide an opportunity to examine levels of reproductive isolation between the taxa involved. We examined phenotypes (morphometric traits and plumage) and genotypes of 175 live birds across the two hybrid zones. We used the Genotyping By Sequencing (GBS) method to identify 180 partially diagnostic single nucleotide polymorphisms (SNPs) to generate a genetic hybrid index (GHI) for each bird. Phenotypically diverged S. ruber and S. nuchalis are genetically closely related, while S. nuchalis and S. varius have similar plumage but are well separated at the genetic markers studied. The width of both hybrid zones is narrower than expected under neutrality, and analyses of both genotypes and phenotypes indicate that hybrids are rare in the hybrid zone. Rarity of hybrids indicates assortative mating and/or some form of fitness reduction in hybrids, which might maintain the species complex despite close genetic distance and introgression. These findings further support the treatment of the three taxa as distinct species. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-30T05:10:32.148442-05:
      DOI: 10.1111/jav.00946
  • Diet and birdsong: short‐term nutritional enrichment improves songs of
           adult Bengalese finch males
    • Authors: Kentaro Yamada; Masayo Soma
      Abstract: Song is a notable sexual signal of birds, and serves as an honest indicator of male quality. Condition dependence of birdsong has been well examined from the viewpoint of the developmental stress hypothesis, which posits that complex songs assure fitness because learned acoustic features of songs are especially susceptible to early‐life stress that young birds experience in song learning periods. The effect of early stress on song phenotypes should be crucial, especially in age‐limited song learners which sing stereotyped songs throughout life. However, little attention has been paid to non‐learned song features that can change plastically even in adulthood of age‐limited song‐learners. Although it has been shown that food availability affects song rate in wild songbirds, there is limited evidence of the link between favorable nutritional conditions and song phenotypes other than song rate. Under the prediction that singing behavior reflects an individual's recent life history, we kept adult Bengalese finch males under high‐nutrition or normal diet for a short term, and examined changes in body mass and songs. We found that birds on a high‐nutrition diet showed higher song output (e.g. song rate and length) compared with those of the control group, while changes in body mass were moderate. In addition, note repertoire became more consistent and temporal structures got faster in both nutrition and control groups, which indicates that songs were subject to other factors than nutrition. Considering that female estrildid finches, including Bengalese and zebra finches, show a preference toward complex songs as well as longer songs and higher song rate, it is plausible that different aspects of singing behavior signal different male qualities, and provide multifaceted clues to females that choose mates. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-30T05:10:22.34568-05:0
      DOI: 10.1111/jav.00979
  • Egg morphology fails to identify nests parasitized by conspecifics in
           common pochard: a test based on protein fingerprinting and including
           female relatedness
    • Abstract: Conspecific brood parasites lay eggs in nests of other females of the same species. A variety of methods have been developed and used to detect conspecific brood parasitism (CBP). Traditional methods may be inaccurate in detecting CBP and in revealing its true frequency. On the other hand more accurate molecular methods are expensive and time consuming. Eadie developed a method for revealing CBP based on differences in egg morphology. That method is based on Euclidean distances calculated for pairs of eggs within a clutch using standardized egg measurements (length, width and weight). We tested the applicability of this method in the common pochard (Aythya ferina) using nests that were identified as parasitized (39 nests) or non‐parasitized (16 nests) based on protein fingerprinting of eggs. We also analyzed whether we can distinguish between parasitic and host eggs in the nest. We found that variation in MED can be explained by parasitism but there was a huge overlap in MED between parasitized and non‐parasitized nests. MED also increased with clutch size. Using discriminant function analysis (DFA) we found that only 76.4% of nests were correctly assigned as parasitized or non‐parasitized and only 68.3% of eggs as parasitic or host eggs. Moreover we found that MED in parasitized nests increased with relatedness of the females that laid eggs in the nest. This finding was supported by positive correlation between MED and estimated relatedness in female‐female pairs. Although variation in egg morphology is associated with CBP, it does not provide a reliable clue for distinguishing parasitized nests from non‐parasitized nests in common pochard. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-30T05:05:29.708326-05:
      DOI: 10.1111/jav.00865
  • Comparative analysis of factors associated with first‐year survival in
           two species of migratory songbirds
    • Authors: Noah G. Perlut; Allan M. Strong
      Abstract: Our understanding of the full life cycle of most migratory birds remains limited. Estimates of survival rates, particularly for first‐year birds are notably lacking. This knowledge gap results in imprecise parameters in population models and limits our ability to fully understand life history trade‐offs. We used eleven years of field data to estimate first‐year apparent survival (ϕ1st) for two species of migratory grassland songbirds that breed in the same managed habitats but have substantially different migration distances. We used a suite of life‐history, habitat and individually‐based covariates to explore causes of variation in ϕ1st. The interaction between fledge date and body mass was the best supported model of apparent survival. We found differential effects of fledging date based on nestling body mass. Overall, lighter nestlings had greater apparent survival than heavier nestlings; average or heavy nestlings within‐brood had greater apparent survival when they fledged earlier in the summer. We hypothesize that heavier birds that fledge earlier in the season have a longer window of opportunity to evaluate potential breeding sites and are more likely to disperse greater distances from the natal region, thus confounding survival with permanent emigration. Lighter birds, particularly those fledged late in the breeding season may spend more time on self‐maintenance and consequently have less time to evaluate potential future breeding sites, showing greater fidelity to their natal region. We found no support for management treatment (timing of mowing), sex, brood size, or species as important covariates in explaining apparent survival. Our results suggest that differential migration distances may not have a strong effect on first‐year apparent survival. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-30T05:05:26.485784-05:
      DOI: 10.1111/jav.00892
  • Responses of King penguin (Aptenodytes patagonicus) adults and chicks to
           two food‐related odours
    • Authors: Gregory B. Cunningham; Sarah Leclaire, Camille Toscani, Francesco Bonadonna
      Abstract: Increasing evidence suggests that penguins are sensitive to dimethyl sulphide (DMS), a scented airborne compound that a variety of marine animals use to find productive areas of the ocean where prey is likely to be found. Here we present data showing that King penguins (Aptenodytes patagonicus) are also sensitive to DMS. We deployed DMS on a lake near a King penguin colony at Ratmanoff beach in the Kerguelen archipelago. We also presented DMS to “sleeping” adults on the beach. On the lake, penguins responded to the DMS deployments by swimming more, while on the beach, penguins twitched their heads and woke up more for the DMS than for the control presentations. Interestingly, penguins did not respond to cod liver oil deployments on the lake; mirroring at‐sea studies of other penguins. Although at‐sea studies are needed to confirm that King penguins use DMS as a surface cue that informs them of productivity under the water, this study is an important first step in understanding how these birds locate prey over significant distances. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-30T05:05:23.287996-05:
      DOI: 10.1111/jav.00863
  • No evidence that genetic compatibility drives extra‐pair behavior in
           female blue‐footed boobies
    • Authors: Lynna Marie Kiere; Alejandra G. Ramos, Hugh Drummond
      Abstract: The function of female birds' extra‐pair (EP) behavior has remained an unresolved question in ornithology and behavioral ecology for >30 years. The genetic compatibility hypothesis (GCH) proposes that females benefit by acquiring biological sires that yield more heterozygous, and therefore fitter, offspring than their social mates. We used ten polymorphic microsatellite loci to test GCH predictions and its assumption that fitness increases with heterozygosity in blue‐footed boobies (Sula nebouxii), a long‐lived tropical seabird. Our predictions were not supported. Heterozygosity was uncorrelated with quality indicators (fledging probability, fledgling or adult body size or mass, adult ornamentation, mean breeding success). Females were no more likely to have EP behavior or chicks when their social mates were less heterozygous or compatible, nor were EP males more heterozygous or compatible than the males they cuckolded. Finally, EP chicks were no more heterozygous than within‐pair chicks overall or in half‐sib comparisons, nor were within‐pair chicks from all‐within‐pair nests more heterozygous that those with EP nest‐mates. There are both methodological and biological explanations for these consistently negative results. Inadequate sample size is possible but unlikely, since our samples were comparable or larger than those of similar studies with significant findings. Lack of identity disequilibrium (within‐individual heterozygosity correlation) among our marker loci could be responsible, and suggests either insufficient marker coverage or lack of inbreeding, bottleneck, and/or admixture. An independent social pedigree revealed infrequent inbreeding, suggesting that pressure on females to select sires that maximize offspring heterozygosity may be genuinely lax. Alternatively, it is possible that the GCH is only upheld when selection on young is strongest; this would not be detected in our sample, which was taken during an extremely productive year. Whatever their cause, our results expand the taxonomic breadth of avian EP behavior analyses and should be considered in future evaluations of the GCH. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-30T05:00:43.949502-05:
      DOI: 10.1111/jav.01061
  • Genetic and paleomodelling evidence of the population expansion of the
           cattle egret Bubulcus ibis in Africa during the climatic oscillations of
           the Late Pleistocene
    • Abstract: Increasing aridity during glacial periods produced the retraction of forests and the expansion of arid and semi‐arid environments in Africa, with consequences for birds. Cattle egret (Bubulcus ibis) is a dispersive species that prefers semiarid environments and requires proximity to bodies of water. We expected that climatic oscillations led to the expansion of the range of the cattle egret during arid periods, such as the Last Maximum Glacial (LGM) and contraction of distribution during the Last Interglacial (LIG) period, resulting in contact of populations previously isolated. We investigated this hypothesis by evaluating the genetic structure and population history of 15 cattle egret breeding colonies located in West and South Africa using the mitochondrial DNA (mtDNA) control region, mtDNA ATPase 8 and 6, and an intron of nuclear gene transforming growth factor beta‐2. Occurrence data and bioclimatic information were used to generate ecological niche models of three periods (present, LGM and LIG). We used the genetic and paleomodelling data to assess the responses of the cattle egret from Africa to the climatic oscillations during the late Pleistocene. Genetic data revealed low levels of genetic differentiation, signs of isolation‐by‐distance, as well as recent increases in effective population size that started during the LGM. The observed low genetic structure may be explained by recent colonization events due to the demographic expansion following the last glacial period and by dispersal capacity of this species. The paleomodels corroborated the expansion during the LGM, and a more restricted potential distribution during the LIG. Our findinds supports the hypothesis that the species range of the cattle egret expanded during arid periods and contracted during wet periods. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-23T04:40:37.500353-05:
      DOI: 10.1111/jav.00972
  • Malaria infection negatively affects feather growth rate in the house
           sparrow (Passer domesticus)
    • Abstract: Birds often face various stressors during feather renewing, for example, enduring infection with blood parasites. Because nutritional resources are typically limited, especially for wild animals, when an individual allocates energy to one physiological system, there is subsequently less for other processes, thereby requiring a trade‐off. Surprisingly, potential trade‐offs between malaria infection and feather growth rate have not been experimentally considered yet. Here, we conducted three studies to investigate whether a trade‐off occurs among feather growth rate, malaria infection and host health conditions. First, we explored whether naturally infected and uninfected house sparrows differed in feather growth rate in the wild. Second, we asked whether experimental inoculation of malaria parasites and / or forcing the renewal of a tail feather. Lastly, we evaluated whether individual condition was affected by experimentally‐induced feather regrowth and / or malaria experimental infection. Our findings showed that feather growth rate was negatively affected by natural malaria infection status in free‐living birds and by experimental infection in captive birds. Furthermore, birds that did not increase body mass or hematocrit during the experimental study had slower feather growth. Together our results suggest that infection with blood parasites has more negative health effects than the growth of tail feathers and that these two processes (response to blood parasite infection and renewal of feathers) are traded‐off against each other. As such, our results highlight the role of malaria parasites as a potential mechanism driving other trade‐offs in wild passerines. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-14T01:11:34.267175-05:
      DOI: 10.1111/jav.00942
  • Natural and anthropogenic influences on the population structure of
           white‐tailed eagles in the Carpathian Basin and Central Europe
    • Abstract: European populations of the white‐tailed eagle (Haliaeetus albicilla) suffered a drastic decline during the 20th century. In many countries, only a few dozen breeding pairs survived or the species disappeared completely. By today, the populations have recovered, naturally or through restocking (e.g. in Scotland or the Czech Republic). In the Carpathian Basin, which is now a stronghold in southern Europe for the species in the southern part of the distribution range with more than 500 breeding pairs, only about 50 pairs survived the bottleneck. This region provides important wintering places for individuals arriving from different regions of Eurasia. In the present study, we investigated 249 DNA samples from several European countries, using 11 microsatellites and mitochondrial control region sequences (499 bp), to answer two main questions: 1) Did the Carpathian Basin population recover through local population expansion or is there a significant gene flow from more distant populations as well? 2) Does the Czech population show signs in its genetic structure of the restocking with birds of unknown origin? Our microsatellite data yielded three genetically separate lineages within Europe: northern, central and southern, the latter being present exclusively in the Carpathian Basin. Sequencing of mitochondrial DNA revealed that there is one haplotype (B12) which is not only exclusive to the Carpathian Basin but it is frequent in this population. Our results suggest that in accordance with the presumably philopatric behaviour of the species, recovery of the Carpathian Basin population was mainly local, but some of the wintering birds coming from the northern and central populations contributed to its genetic composition as well. We detected considerably higher proportions of northern birds within the Czech Republic compared to the neighbouring areas, making it likely that parents of the reintroduced birds came from northern populations. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-14T01:11:17.956074-05:
      DOI: 10.1111/jav.00938
  • Nest building under the risk of predation: safe nests are not always the
           best option
    • Authors: Jong Koo Lee; Steven L. Lima
      Abstract: Nest predation is a widespread demographic and evolutionary force in avian reproduction, but few studies have considered the circumstances under which birds might invest in the construction of safe nests. We examined this question using a stochastic simulation model based on a basic passerine breeding season. Nest safety functions were used to translate time invested in nest building into an increase in daily nest survival; that increase could be rapid, requiring only a few days to achieve a safe nest, or slow, taking many days to do so. The maximum achievable safety differed across nest safety functions. Given a limited length to the breeding season, a greater time investment in nest safety detracts from the time available for re‐nesting following successful or unsuccessful nesting attempts. In many circumstances, the best option is a quick‐build “minimal” nest that provides adequate support for young, but little additional safety from attacks. This is especially true for scenarios that allow for multiple nesting attempts across a season. However, relatively safe nests that can be built fairly quickly are uniformly favored options. Safe, long‐build nests are favored only when they provide a great deal of safety over other nest‐building options, but greater safety alone is not sufficient for such investment. Simulations allowing only a single nesting attempt generally favor a greater investment in nest safety. Parental survival is another important factor in nest investment. Increased danger to the parent during nest building strongly favors a low investment in nests. However, substantial investment in a safe nest is favored when that safety extends to the incubating parent. Our results provide some insight into the prevalence of seemingly unsafe, open‐cup nests across the bird world, but the range of nest types that could potentially be built by a given species is an open question. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-14T01:10:59.712585-05:
      DOI: 10.1111/jav.00958
  • Adaptability of a specialist predator: The effects of land use on diet
           diversification and breeding performance of Verreaux's eagles
    • Authors: M. Murgatroyd; G. Avery, L.G. Underhill, A. Amar
      Abstract: Specialist predators are generally negatively impacted by habitat change. Predators that inhabit transformed areas are usually forced to diversify their diet and this departure away from traditional resources can have negative consequences for fitness and demographic parameters. We consider this relationship as it applies to Verreaux's eagles Aquila verreauxii, which is typically considered to be a highly specialised predator of hyraxes (Procavia and Heterohyrax spp.). We investigate diet in relation to land cover in two adjacent areas of South Africa and explore the links between diet diversity, the percentage of hyrax consumed, and the breeding performance of eagles. We also examine these same patterns using data from other studies. We found that diet diversity was greater in the agriculturally developed Sandveld region compared to the natural Cederberg region. Proportions of the three main prey types were correlated with the proportion of agriculturally developed land around the nest site. Breeding performance was correlated with the diet, but not in the manner expected, with breeding productivity being greater in regions with large diet diversity and a small proportion of hyrax in the diet. We found similar patterns when placing our results into a broader geographical context using other dietary studies of Verreaux's eagles, suggesting our results were not unique to our study system. Thus, our results suggest that diet diversification does not necessarily impinge on breeding performance in the presence of adequate alternative prey resources. This research adds to the growing number of studies suggesting that some predators may be adaptable up to a threshold level of habitat transformation. These results have implications for predicting changes on such species by anthropogenic habitat transformation and highlight the potential for agriculturally developed areas to maintain a conservation value when habitat heterogeneity is maintained. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-14T01:10:41.600628-05:
      DOI: 10.1111/jav.00944
  • Spatial patterns of extra‐pair paternity for spotted towhees (Pipilo
           maculatus) in urban parks
    • Authors: Sarah Bartos Smith; Jenny E. Mckay, Michael T. Murphy, Deborah A. Duffield
      Abstract: The extra‐pair (EP) mating system of birds may be influenced by food resources, such that nutritionally stressed females are unable to pursue EP fertilizations (constrained female hypothesis; CFH), or that females on poor territories acquire EP fertilizations during extra‐territorial forays in search of food (mating opportunity hypothesis; MOH). Edges of urban habitat fragments are sites of apparent high food abundance for spotted towhees (Pipilo maculatus), and we used distance to habitat edge in four urban parks in Portland, OR, USA (2004‐2006), to test the CFH and MOH. EP paternity was independent of park identity and year; 44% of nests contained EP young and 26% of all young were EP. As predicted by the CFH, EP paternity was more common in nests of long‐tailed (presumably) high quality females. However, independently of tail length, younger females had more EP young than older females, a finding consistent with the MOH. Contrary to predictions of both hypotheses, the probability that a nest contained EP young was highest both at the habitat edge and habitat interior while the proportion of young in nests of EP origin (for nests with EP young) was highest at intermediate distances from habitat edge. We propose that high frequency of EP paternity among females in the interior occurred because, as predicted by the MOH, they ranged more widely in search of food and often encountered EP males. High probability of EP paternity near edges was likely unrelated to female quality. Instead, anthropogenic food sources may have attracted individuals to edges and increased encounters between potential EP mates. Simple opportunity seems likely to account for patterns of EP paternity in spotted towhees, suggesting that human altered environments have the potential to substantially affect EP mating behavior. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-13T05:46:33.09231-05:0
      DOI: 10.1111/jav.00931
  • Communal roosting, thermoregulatory benefits and breeding group size
           predictability in cooperatively breeding sociable weavers
    • Authors: Matthieu Paquet; Claire Doutrelant, Maxime Loubon, Franck Theron, Margaux Rat, Rita Covas
      Abstract: Extreme temperatures impose energy costs on endotherms through thermoregulation and different adaptations help individuals to cope with these conditions. In social species, communal roosting and huddling are thought to decrease the energetic requirement of thermoregulation under low temperatures. This is likely to represent an important mechanism by which individuals save energy during the coldest parts of the year and hence to represent a non‐breeding benefit of sociality. Here, we investigate the potential thermoregulatory benefits of group living in roosting groups of sociable weavers Philetairus socius, a colonial cooperatively breeding passerine that builds communally a massive nest structure with several independent chambers wherein individuals breed and roost throughout the year. To investigate the benefits of sociality during the non‐breeding season, we studied the thermal environment during roosting in relation to group size. In addition, to understand the link between non‐breeding and breeding sociality in this species we studied group size stability between the pre‐breeding and breeding periods. As expected, we found that the nest chamber's night‐time temperature is strongly related to the number of birds roosting together, especially during cold nights. Specifically, birds in larger groups spent less time below the critical thermal minimum temperature (i.e. the temperature below which energy expenditure increases substantially). They were less exposed to external temperature variations. We also found a positive relationship between the number of birds roosting during winter and the breeding group size, indicating breeding group size predictability. In cooperative breeders such as the sociable weaver, the costs and benefits of sociality are usually studied during the breeding period. This study shows that a better understanding of non‐breeding benefits of group membership and group dynamics between the non‐breeding and breeding periods are necessary for a comprehensive understanding of the benefits of sociality. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-13T05:46:30.743317-05:
      DOI: 10.1111/jav.00916
  • Coastal saltpans are a good alternative breeding habitat for Kentish
           plover Charadrius alexandrinus when umbrella species are present
    • Abstract: The loss and degradation of natural habitats in coastal areas worldwide has adversely affected many waterbird species, changing their breeding distribution and reducing their productivity. Anthropogenic habitats such as saltpans can provide alternative or complementary habitats for waterbirds and mitigate the increasing human impact on natural coastal habitats. Unvegetated linear paths between salt ponds are used by ground‐nesting waterbird species to breed but their linear structure may facilitate the detection of nests by predators. This negative effect may, however, be counterbalanced by the advantages of breeding in mixed colonies. To evaluate the importance and the risks of breeding in saltpans we used the Kentish plover Charadrius alexandrinus breeding in coastal saltpans of southern Portugal as a model species. Specifically, we assessed the role of nest‐site characteristics, predation and nesting proximity to species with aggressive antipredator behaviour (Black‐winged stilt Himantopus himantopus) on their breeding success. Kentish plovers selected nest‐sites on the edges of paths, with about 20% of water around the nest, and a mean visibility of more than 72 %; however nest‐site characteristics were not correlated with nesting success. Predation was the main cause of nest loss in saltpans (42%); Carrion crows Corvus corone were responsible for most daylight nest predation (58%) and Red fox (Vulpes vulpes; 73%) for night predation. An 8‐year monitoring plan of a Kentish plover population showed a linear increase in their breeding success as their breeding season increasingly overlapped with that of the Black‐winged stilt. An experiment with artificial nests showed a significant increase in the number of exposure days (7 to 12) when these nests were within close distance of Black‐winged stilt nests. Overall, our results showed that saltpans are an important alternative breeding habitat for the Kentish plover, especially for the maintenance of mixed species colonies. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-13T05:46:01.453-05:00
      DOI: 10.1111/jav.00883
  • Body mass change and diet switch tracked by stable isotopes indicate time
           spent at a stopover site during autumn migration in dunlins (Calidris
           alpina alpina)
    • Abstract: Birds may change their diet and foraging habitat during or after migration. Dunlins (Calidris alpina alpina) breed in the tundra of northern Europe and Russia where they feed exclusively on terrestrial prey. However, up to 80% of the flyway population uses the Wadden Sea as their first important staging site on the way to wintering grounds, feeding exclusively on marine prey. Adult birds migrate earlier than immatures and tend to fly non‐stop, whereas immatures may stage for at least a few days en route, mainly in the Baltic region. There they mostly feed on brackish water prey showing similar isotopic values compared to terrestrial prey. When they arrive in the Wadden Sea, dunlin body reserves are depleted and lower than those of individuals that have already staged for several days. We hypothesized that lighter individuals should retain a strong terrestrial isotopic blood signature, while heavier ones should show a stronger marine signature. We found a significant positive correlation between scaled mass index and carbon (δ13C) and nitrogen (δ15N) stable isotopes, reflecting the switch from terrestrial to marine prey during migration. A mixing model revealed differences in isotopic values between heavy and light adults and immatures, respectively, in relation to the isotopic prey signatures. Adults showed stronger marine signals compared with immatures, emphasizing the different modes of migration (i.e. a later departure in immatures) as well as the known spatial segregation of age classes in the Wadden Sea, i.e. adults use tidal flats distant from the shore while immatures use coastal areas influenced by terrestrial carbon sources. The results of this study demonstrate the value of scaled mass index in migratory birds as an indicator of time elapsed after diet switching following migration. Furthermore, this study extents the existing knowledge on the timing of dunlin migration by using an isotopic approach. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-13T05:45:58.516317-05:
      DOI: 10.1111/jav.00873
  • Egg rejection and clutch phenotype variation in the plain prinia (Prinia
    • Abstract: Avian hosts of brood parasites can evolve anti‐parasitic defenses to recognize and reject foreign eggs from their nests. Theory predicts that higher inter‐clutch and lower intra‐clutch variation in egg appearance facilitates hosts to detect parasitic eggs as egg‐rejection mainly depends on the appearance of the egg. Therefore, we predict that egg patterns and rejection rates will differ when hosts face different intensity of cuckoo parasitism. We tested this prediction in two populations of the plain prinia (Prinia inornata): Guangxi in mainland China with high diversity and density of cuckoo species, and Taiwan where there is only one breeding cuckoo species, the Oriental cuckoo (Cuculus optatus). As expected, egg patterns were similar within clutches but different among clutches (polymorphic eggs) in the mainland population, while the island population produced more uniform egg morphs. Furthermore, the mainland population showed a high rate of egg rejection, while the island population exhibited dramatically reduced egg grasp‐rejection ability in the absence of parasitism by the common cuckoo (Cuculus canorus). Our study suggests that prinias show lower intra‐clutch consistency in egg colour and lose egg‐rejecting ability under relaxed selection pressure from brood parasitism. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-13T05:12:01.47735-05:0
      DOI: 10.1111/jav.00786
  • Cross‐continental migratory connectivity and spatiotemporal migratory
           patterns in the great reed warbler
    • Abstract: Migratory connectivity describes to which degree different breeding populations have distinct (non‐overlapping) non‐breeding sites. Uncovering the level of migratory connectivity is crucial for effective conservation actions and for understanding of the evolution of local adaptations and migratory routes. Here we investigate migration patterns in a passerine bird, the great reed warbler Acrocephalus arundinaceus, over its wide Western Palearctic breeding range using geolocators from Spain, Sweden, Czech Republic, Bulgaria and Turkey. We found moderate migratory connectivity: a highly significant spatial structure in the connections between breeding and sub‐Saharan non‐breeding grounds, but at the same time a partial overlap between individual populations, particularly along the Gulf of Guinea where the majority of birds from the Spanish, Swedish and Czech populations spent their non‐breeding period. The post‐breeding migration routes were similar in direction and rather parallel for the five populations. Birds from Turkey showed the most distinctive migratory routes and sub‐Saharan non‐breeding range, with a post‐breeding migration to East Africa and, together with birds from Bulgaria, a previously unknown pre‐breeding migration over the Arabian Peninsula indicating counter‐clockwise loop migration. The distances between breeding and sub‐Saharan non‐breeding sites, as well as between first and final sub‐Saharan non‐breeding sites, differed among populations. Moreover, the total speed of migration did not differ significantly between populations during both the post‐breeding migration in autumn as well as during pre‐breeding migration in spring. There was also no significant relationship between the total speed of migration and distance between breeding and non‐breeding sites (neither post‐ nor pre‐breeding) and, surprisingly, the total speed of migration generally did not differ significantly between post‐breeding and pre‐breeding migration. Future challenges include understanding whether non‐breeding environmental conditions may have influenced the differences in migratory patterns that we observed between populations, and to which extent non‐breeding habitat fluctuations and loss may affect population sizes of migrants. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-15T07:25:35.241202-05:
      DOI: 10.1111/jav.00929
  • Re‐evaluating the distribution of cooperative breeding in birds: is it
           tightly linked with altriciality'
    • Authors: Ning Wang; Rebecca T. Kimball
      Abstract: The evolution of cooperative breeding (CB) in birds has aroused intensive interest for decades, largely due to the paradox that some adults forgo independent breeding to help others. While much effort has been directed at understanding the adaptive significance of CB behavior, much less effort has been spent on understanding its origin. Ligon and Burt [2004, pp5‐34, Cambridge, UK] argued that the evolution of altriciality played a key role in the origin of CB since CB occurs more frequently in altricial lineages than expected if developmental mode and CB evolved independently and that both traits arose early in the avian tree of life. We mapped presence or absence of CB, and precocial or altricial development on a recent phylogeny of all birds to re‐evaluate their conclusions. Our results suggest altriciality may be more recently derived than previously thought, and that CB species clustered in a derived land bird clade (especially within Passeriformes) where we reconstructed many gains and losses. We did find a link between cooperative breeding and altriciality. However, since CB also occurs in precocial species, has not evolved in many altricial clades, and may have evolved prior to altriciality (based on some classifications of which species have CB), it is not clear whether altriciality is linked to other factors, such as benefits to group living, that are necessary for the acquisition of CB behavior, or whether altriciality may have been a driving force in the evolution of CB itself. The relative importance of these other factors versus altriciality for the origin of CB needs to be considered. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-10T11:14:06.063493-05:
      DOI: 10.1111/jav.00869
  • Weak geographical structure in sperm morphology across the range of two
           willow warbler Phylloscopus trochilus subspecies in Scandinavia
    • Abstract: Sperm morphology is highly diversified among species and at higher taxonomic levels. In birds, there is also increasing evidence of geographical differentiation in sperm traits within species, especially in those with strong sperm competition. Geographical divergences in sperm traits might imply the formation of a reproductive barrier in a speciation process. Here we study sperm morphology variation of willow warblers Phylloscopus trochilus in a geographical context in Scandinavia, across the range of two subspecies that are differentiated in certain genetic markers, morphology and migratory routes. We describe geographical patterns in genotypes (two previously described single‐nucleotide polymorphism (SNP) markers and four polymorphic microsatellites); in wing length, tarsus length and body mass; and in sperm traits of 330 male willow warblers sampled at 33 localities across Norway (58o N – 69o N). Birds were on average larger and longer‐winged in the north (spp. acredula) than in the south (spp. trochilus), and showed a sigmoid change in the SNP allele frequencies and body morphology around 65o N. We found no evidence of genetic structuring in the microsatellites. There was no geographical variation in sperm traits across Norway, except that sperm heads were on average longer in the south. Sperm head length was also associated with the two SNP markers, with longer sperm heads for the southern alleles, and midpiece length was weakly associated with one of the SNP markers. Similar among‐male variances in total sperm length among the 33 sampling sites indicate uniform levels of sperm competition across Norway. We conclude that sperm morphology remains a rather undifferentiated trait between the two willow warbler subspecies in Scandinavia, which is consistent with a pattern of a shallow genetic divergence. This indicates that sperm morphology is not a reproductive barrier maintaining the narrow hybrid zone. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-10T11:12:29.54237-05:0
      DOI: 10.1111/jav.00981
    • Abstract: Direct benefits accrued from securing a territory of sufficient quality are important determinants of individual fitness and population persistence. Food supply is one of the main factors of animal territory quality, with spatial and temporal variation in prey availability largely dictating reproductive output and thus population dynamics. In a Swiss hoopoe population, molecrickets Gryllotalpa gryllotalpa, the most profitable prey locally, can constitute most of the food biomass delivered to chicks by parents. We first investigated the impact of molecricket prey on hoopoes' fitness‐related traits by quantifying the spatial variation in the food allocation pattern of both male and female parents to chicks across the whole population range; and second, analysed the impact of this prey on current reproduction and, using a 11 year dataset, on the temporal occupancy rate of each territory. We found considerable but spatially repeatable variation, over the years, of molecricket biomass in the diet provisioned to chicks. This spatial heterogeneity in chicks' diet composition was mirrored both in the history of territory occupancy (2002‐2012) and in current reproductive success (2012). Territories with a greater biomass of molecrickets in chicks' diet produced more fledglings in better body condition. Yet, these effects on current reproduction were exclusively demonstrated for male parents, corroborating that paternal provisioning patterns play a predominant role in hoopoe reproductive success. This study demonstrates how a single, very profitable prey species might affect spatial variation in territory settlement and individual reproductive success in a regionally endangered bird species, with potential consequences for its population dynamics and persistence. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-10T11:11:54.498216-05:
      DOI: 10.1111/jav.00990
    • Authors: Danny Caudill; Michael R. Guttery, Erin Leone, Gretchen Caudill, Terry A. Messmer
      Abstract: Research on iteroparous species has shown that reproductive success may increase with age until the onset of senescence. However, from the population perspective, increased reproductive success with age could be a consequence of within‐individual variation (e.g., ageing, breeding experience, foraging ability hypotheses), between‐individual variation (e.g, individual heterogeneity, frailty, selection, delayed breeding hypotheses), or a combination thereof. We evaluated within‐ and between‐individual variation in reproductive success of greater sage‐grouse (Centrocercus urophasianus; sage‐grouse), a galliforme of conservation concern throughout western North America. We monitored female reproductive activity from 1998–2010 and used generalized linear mixed models incorporating within‐subject centering to evaluate and separate within‐ and between‐individual effects. We detected positive effects of within‐individual variation on nest initiation and success where ageing increased the likelihood of both parameters, which appears to support the breeding experience and/or foraging ability hypotheses. However, nest initiation was also affected by between‐individual variation whereby the likelihood of initiation was higher for individuals with higher mean age (i.e., survived longer), as is predicted by the frailty and selection hypotheses. Our results indicate both within‐ and between‐individual variation affect reproductive output of sage‐grouse, but the effects of each varied by measure of reproductive output. Our results corroborate previous findings that suggest population age parameters (i.e., cross‐sectional) should be interpreted with caution due to potential entanglement of within‐ and between‐individual processes. Moreover, the relative role and strength of within‐ and between‐individual processes appeared to vary by measure of reproductive output in our results, which further emphasizes the need for longitudinal analysis of age effects, even in relatively short‐lived iteroparous animals, to adequately interpret biological processes. This article is protected by copyright. All rights reserved.
      PubDate: 2016-03-10T11:10:35.861244-05:
      DOI: 10.1111/jav.00903
  • Characterization of the gut microbiota of migratory passerines during
           stopover along the northern coast of the Gulf of Mexico
    • Authors: William B. Lewis; Frank R. Moore, Shiao Wang
      Abstract: Although the gut microbiota is known to provide many beneficial functions to animal hosts, such as aiding in digestion, fat metabolism, and immune function, relatively little is known about the gut microbiota of passerines. Gut microbes may have both beneficial and detrimental impacts on the fitness of migratory passerines; however physiological and morphological changes associated with prolonged migratory flight may cause disruptions of the stable microbiota and potentially a loss of function. Fecal samples were collected from Swainson's Thrushes (Catharus ustulatus) and Gray Catbirds (Dumetella carolinensis) immediately after crossing the Gulf of Mexico during spring migration and before crossing during fall, and microbiota communities were analyzed using next‐generation sequencing. Microbiota communities were generally dominated by Firmicutes and Proteobacteria, with potential pathogens as well as potentially beneficial bacteria identified in all birds. Energetic condition of migrants was not significantly related to overall microbiota community structure though it cannot be conclusively stated that migratory flight does not impact the microbiota. Spring and fall migrants showed clear differences in microbiota communities, indicating that environmental factors influence the gut microbiota of these species more than host genetics. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-24T20:21:40.218635-05:
      DOI: 10.1111/jav.00954
  • A Synthesis of Species Interactions, Metacommunities, and the Conservation
           of Avian Diversity in Hemiboreal and Boreal Forests
    • Authors: Alexis R. Grinde; Gerald J. Niemi
      Abstract: The rate at which climate is changing in northern latitudes presents a significant threat to bird populations that rely on boreal forests. Alterations in the distributions of trees and other plants as a result of warming will alter the habitat suitability of vast regions of boreal and hemiboreal forests. Climate change associated habitat alterations along with range expansions of bird species are likely to have substantial consequences on avian communities and biodiversity. Identifying factors that contribute to species coexistence and community assembly processes at local and regional scales will facilitate predictions about the impact of climate change on avian communities in these forest ecosystems. This paper provides a comprehensive review of historic and current theories of community ecology dynamics providing a theoretical synthesis that links the evolution of species traits at the individual level, the dynamics of species interactions, and the overall maintenance of biodiversity. Integration of these perspectives is necessary to provide the scientific means to face growing environmental challenges in boreal ecosystems. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-24T20:21:12.965909-05:
      DOI: 10.1111/jav.01036
  • Individual variation in winter supplementary food consumption and its
           consequences for reproduction in wild birds
    • Authors: Ross A. Crates; Josh A. Firth, Damien R. Farine, Colin J. Garroway, Lindall R. Kidd, Lucy M. Aplin, Reinder Radersma, Nicole D. Milligan, Bernhard Voelkl, Antica Culina, Brecht L. Verhelst, Camilla A. Hinde, Ben C. Sheldon
      Abstract: The provision of wild birds with supplementary food has increased substantially over recent decades. While it is assumed that provisioning birds is beneficial, supplementary feeding can have detrimental ‘carry‐over’ effects on reproductive traits. Due to difficulties in monitoring individual feeding behaviour, assessing how individuals within a population vary in their exploitation of supplementary food resources has been limited. Quantifying individual consumption of supplementary food is necessary to understand the operation of carry‐over effects at the individual level. We used Radio Frequency Identification (RFID) technology and automated feeders to estimate individual consumption of supplementary winter food in a large wild population of great tits Parus major and blue tits Cyanistes caeruleus. Using these data, we identified demographic factors that explained individual variation in levels of supplementary food consumption. We also tested for carry‐over effects of supplementary food consumption on recruitment, reproductive success and a measure of survival. Individual variation in consumption of supplementary food was explained by differences between species, ages, sexes and years. Individuals were consistent across time in their usage of supplementary resources. We found no strong evidence that the extent of supplementary food consumption directly influenced subsequent fitness parameters. Such effects may instead result from supplementary food influencing population demographics by enhancing the survival and subsequent breeding of less competitive individuals, which reduce average breeding parameters and increase density‐dependent competition. Carry‐over effects of supplementary feeding are not universal and may depend upon the temporal availability of the food provided. Our study demonstrates how RFID systems can be used to examine individual‐level behaviour with minimal effects on fitness. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-24T11:03:25.163461-05:
      DOI: 10.1111/jav.00936
  • Mitochondrial rate variation among lineages of passerine birds
    • Authors: Jacqueline M. T. Nguyen; Simon Y. W. Ho
      Abstract: The order Passeriformes comprises the majority of extant avian species. Analyses of molecular data have provided important insights into the evolution of this diverse order. However, molecular estimates of the evolutionary and demographic timescales of passerine species have been hindered by a lack of reliable calibrations. This has led to a reliance on the application of standard substitution rates to mitochondrial DNA data, particularly rates estimated from analyses of the gene encoding cytochrome b (CYTB). To investigate patterns of rate variation across passerine lineages, we used a Bayesian phylogenetic approach to analyse the protein‐coding genes of 183 mitochondrial genomes. We found that the most commonly used mitochondrial marker, CYTB, has low variation in rates across passerine lineages. This lends support to its widespread use as a molecular clock in birds. However, we also found that the patterns of among‐lineage rate variation in CYTB are only weakly related to the evolutionary rate of the mitochondrial genome as a whole. Our analyses confirmed the presence of mutational saturation at third codon positions across the protein‐coding genes of the mitochondrial genome, reinforcing the view that these sites should be excluded in studies of deep passerine relationships. The results of our analyses have provided information that will be useful for molecular‐clock studies of passerine evolution. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-24T10:41:58.344008-05:
      DOI: 10.1111/jav.00928
  • Survival to independence in relation to pre‐fledging development and
           latitude in songbirds across the globe
    • Abstract: Species differ strongly in their life histories, including the probability of survival. Annual adult survival was investigated extensively in the past, whereas juvenile survival, and especially survival to independence, received much less attention. Yet, they are critical for our understanding of population demography and life‐history evolution. We investigated post‐fledging survival to independence (i.e. survival upon leaving the nest until nutritional independence) in 74 species of passerine birds worldwide based on 100 population level estimates extracted from published literature. Our comparative analyses revealed that survival to independence increased with the length of nestling period and relative fledging mass (ratio of fledging mass to adult body mass). At the same time, species with higher nest predation rates had shorter nestling periods and lower relative fledging mass. Thus, we identify an important trade‐off in life history strategies: staying longer in the nest may improve post‐fledging survival due to enhanced flight ability and sensory functions, but at the cost of a longer exposure to nest predators and increased mortality due to nest predation. Additionally, post‐fledging survival to independence did not differ between species from the northern temperate zone vs. species from the tropics and southern hemisphere. However, analyses of post‐fledging survival curves suggest that i) daily survival rates are not constant and improve quickly upon leaving the nest, and ii) species in the tropics and southern hemisphere have higher daily post‐fledging survival rates than northern temperate species. Nevertheless, due to the accumulation of mortality risk during their much longer periods of post‐fledging care, overall survival until independence is comparable across latitudes. Obtaining high‐quality demographic data across latitudes to evaluate the generality of these findings and mechanisms underlying them should be a research priority. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-24T10:41:20.257554-05:
      DOI: 10.1111/jav.00841
  • MHC‐I provides both quantitative resistance and susceptibility to blood
           parasites in blue tits in the wild
    • Abstract: Major histocompatibility complex (MHC) genes are central for the adaptive immune response against parasites. Here, we investigated potential associations among MHC‐I alleles and blood parasite infections in a natural breeding population of a passerine bird, the blue tit Cyanistes caeruleus, in central Spain. We screened both infection status (presence/absence of infection) and infection intensity to the pathogenic blood parasites Haemoproteus and Leucocytozoon. Three MHC‐I alleles (UA104, UA108 and UA117) were associated with higher or lower infection intensities by Leucocytozoon. Interestingly, these associations were dependent on age and were found both among young and adult birds. No MHC alleles were associated with infection intensity by Haemoproteus parasites. In addition, no significant relationships were detected between infection status by Haemoproteus and Leucocytozoon infections and MHC alleles. The very high prevalence of these two parasites in our study population (79–100%) poses challenges to identify associations with infection status and also suggests that clearance of infections may be rare. In conclusion, associations between specific MHC‐I alleles and Leucocytozoon parasites were related to either high or low infection intensities, and hence increased susceptibility or resistance to infection. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-24T10:40:45.164773-05:
      DOI: 10.1111/jav.00830
  • Estimating the abundance of burrow‐nesting species through the
           statistical analysis of combined playback and visual surveys
    • Abstract: 1. The conservation of elusive species relies on our ability to obtain unbiased estimates of their abundance trends. Many species live or breed in cavities, making it easy to define the search units (the cavity) yet hard to ascertain their occupancy. One such example is that of certain colonial seabirds like petrels and shearwaters, which occupy burrows to breed. In order to increase the chances of detection for these types of species, their sampling can be done using two independent methods to check for cavity occupancy: visual inspection, and acoustic response to a playback call. 2. This double‐detection process allows us to estimate the probability of burrow occupancy by accounting for the probability of detection associated with each method. Here we provide a statistical framework to estimate the occupancy and population size of burrow‐dwelling species. We show how to implement the method using both Maximum Likelihood and Bayesian approaches, and test its precision and bias using simulated datasets. We subsequently illustrate how to extend the method to situations where two different species may occupy the burrows, and apply it to a dataset on Wedge‐tailed shearwaters Puffinus pacificus and Tropical shearwaters P. bailloni on Aride Island, Seychelles. 3. The simulations showed that the single‐species model performed well in terms of error and bias except when detection probabilities and occupancies were very low. The two‐species model applied to shearwaters showed that detection probabilities were highly heterogeneous. The population sizes of Wedge‐tailed and Tropical shearwaters were estimated at 13,716 (95% CI: 12,909 ‐ 15,874) and 25,550 (23,667 ‐ 28,777) pairs respectively. 4. The advantages of formulating the call‐playback sampling method statistically is that it provides a framework to calculate uncertainty in the estimates and model assumptions. This method is applicable to a variety of cavity‐dwelling species where two methods can be used to detect cavity occupancy. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-01T02:44:54.365892-05:
      DOI: 10.1111/jav.00909
  • Plasticity in moult speed and timing in an arctic‐nesting goose
    • Abstract: Environmental constraints are strong in migratory species that breed in the Arctic. In addition to breeding, Anatidae have to renew all their flight feathers during the short arctic summer. We examine how temporal constraints and climate affect the phenology of flight feather moult in the greater snow goose (Chen caerulescens atlantica), a High Arctic nesting species. We used a database of 1412 moulting adult females measured over 15 years on Bylot Island, Nunavut. Ninth (9th) primary length was used to determine the moult stage and speed of feather growth. We found a positive relationship between median annual hatching and moult initiation dates and the slope did not differ from 1. The interval between hatching and moult initiation was thus rather fixed and geese did not initiate moult earlier when reproductive phenology was delayed. Nonetheless, there was no relationship between median hatching date and the date at which birds regained flight capacity, suggesting that date of end of moult is independent of the reproductive phenology. There was a trend for an increase in the speed of flight feather growth in years with delayed hatching date. This is the most likely mechanism that could explain moult phenology adjustment in this species. Finally, we found a positive relationship between 9th primary length (corrected for inter‐annual variations) and body condition, suggesting a delay in moulting for individuals in poor condition. These results suggest that moult plasticity is primarily governed by variations in feather growth speed. This phenotypic plasticity could be necessary to complete flight feather renewal before the end of the arctic summer, independently of reproductive phenology and spring environmental conditions. Our novel results suggest possible phenological adjustments through moult speed, which was considered constant in geese until now. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-01T02:39:01.565117-05:
      DOI: 10.1111/jav.00982
  • Inter‐annual variability and long‐term trends in breeding success in a
           declining population of migratory swans
    • Authors: Kevin A. Wood; Julia L. Newth, Geoff M. Hilton, Bart A. Nolet, Eileen C. Rees
      Abstract: Population declines among migratory Arctic‐breeding birds are a growing concern for conservationists. To inform the conservation of these declining populations, we need to understand how demographic rates such as breeding success are influenced by combinations of extrinsic and intrinsic factors. In this study we examined inter‐annual variation and long‐term trends in two aspects of the breeding success of a migratory herbivore, the Bewick's Swan (Cygnus columbianus bewickii), which is currently undergoing a population decline: (i) the percentage of young within the wintering population and (ii) mean brood size. We used an information‐theoretic approach to test how these two measures of productivity were influenced over a 26 year period by 12 potential explanatory variables, encompassing both environmental (e.g. temperature) and intrinsic (e.g. pair‐bond duration) factors. Swan productivity exhibited sensitivity to both types of explanatory variable. Fewer young were observed on the wintering grounds in years in which the breeding period (May to September) was colder and predator (Arctic Fox) abundance was higher. The percentage of young within the wintering population also showed negative density‐dependence. Inter‐annual variance in mean swan brood size was best explained by a model comprised of the negative degree days during the swan breeding period, mean pair‐bond duration of all paired swans (i.e. mean pair duration), and an interaction between these two variables. In particular, mean pair duration had a strong positive effect on mean brood size. However, we found no long‐term directional trend in either measure of breeding success, despite the recent decline in the NW European population. Our results highlight that inter‐annual variability in breeding success is sensitive to the combined effects of both intrinsic and extrinsic factors. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-21T02:26:59.05457-05:0
      DOI: 10.1111/jav.00819
  • Maternal transfer of androgens in eggs is affected by food supplementation
           but not by predation risk
    • Abstract: Mothers may affect the future success of their offspring by varying allocation to eggs and embryos. Allocation may be adaptive based on the environmental conditions perceived during early breeding. We investigated the effects of food supplementation and predation risk on yolk hormone transfer in the pied flycatcher (Ficedula hypoleuca). In a food supplementation experiment, females were food‐supplemented prior to and during egg‐laying and androgen concentrations were measured throughout the laying order. Predation risk was investigated in three different studies combining both correlative data, where flycatchers bred in close proximity to two different predator species that prey upon adult flycatchers (either Tengmalm's owl, Aegolius funereus or pygmy owl, Glaucidium passerinum), and an experimental manipulation, where flycatchers were exposed to cues of a nest predator (least weasels, Mustela nivalis). Females receiving food supplementation laid eggs with lower concentrations of androstenedione (A4) than females not receiving food supplements. Yolk testosterone (T) concentration showed the same pattern but the difference was not statically significant. Testosterone (but not A4) concentration increased within clutches, from the first to the last egg, independently of the food supplementation. Females breeding under high predation risk did not differ from control females in their yolk androgen levels (A4, T or progesterone). However, concentrations of A4 tended to be lower in the proximity of pygmy owls, which could indirectly increase offspring survival after fledging. Food supplementation during egg‐laying seems to have a stronger impact on maternal transfer of androgens than predation risk. Food availability and predation risk could differentially affect the trade‐offs of androgen allocation for the offspring when raised in good vs. dangerous environments. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-21T02:26:43.252329-05:
      DOI: 10.1111/jav.00874
  • Differences in shifts of wintering and breeding ranges lead to changing
           migration distances in European birds
    • Abstract: Studies on the impact of climate change on the distributions of bird species in Europe have largely focused on one season at time, especially concerning summer breeding ranges. We investigated whether migratory bird species show consistent range shifts over the past 55 years in both breeding and wintering areas or if these shifts are independent. We then analyzed whether patterns in changing migration distances of Finnish breeding birds could be explained by habitat use, phylogeny or body size. We used long‐term datasets from the Finnish ringing centre to analyze the mean wintering latitudes of 29 species of Finnish breeding birds, then used breeding distribution data to make predictions as to whether certain species were migrating shorter or longer distances based on the comparative shifts in the wintering and breeding grounds. Our data reveal species‐specific differences in changing migration distances. We show that for many species, long‐term shifts in wintering ranges have not followed the same patterns as those in the breeding range, leading to differences in migration distances over time. We conclude that species are not adjusting predictably to climate change in their wintering grounds, leading to changing migration distances in some, but not all, species breeding in Finland. This research fills an important gap in the current climate change biology literature, focusing on individuals' entire life histories and revealing new complexities in range shift patterns. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-21T02:25:54.622704-05:
      DOI: 10.1111/jav.00941
  • Helper effects in the azure‐winged magpie Cyanopica cyana in relation to
           highly‐clumped nesting pattern and high frequency of conspecific
    • First page: 449
      Abstract: In avian cooperative breeding systems, many benefits obtained by social pairs from the presence of helpers have been uncovered. However, until now, the factors that determine the type of assistance helpers provide and the responses of social pairs have not been well illustrated. We examined the contribution of helpers to cooperative groups and the relevant responses of dominant pairs in the azure‐winged magpie, Cyanapica cyana, which breeds on the Tibetan Plateau. We used the capture‐mark‐recapture method to identify helpers. Results showed that helpers were mostly the yearling sons of dominant pairs. They mainly contributed to the cooperative group in three ways, courtship‐feeding the incubation female, provisioning the brood, and defending the nest. For responses of dominant pairs, we unexpectedly found that clutch size was not influenced by the presence of helpers at the nest. However, cooperative groups had higher brood feeding rates than biparental nests and their feeding pattern also differed to that of the latter. Consequently, nestlings in cooperative groups had larger fledging body mass than that in biparental nests. By examining reasons for nest failure, we revealed that conspecific nest‐raiding contributed to more nest failure than any other natural predators. Because of the contribution of helpers in defending against both predators and conspecific nest‐raiders, cooperative groups had higher survival rate than biparental nests. Thus, our findings suggest that in a highly‐clumped nesting pattern, factors concerning the risk of nest predation, rather than that influencing food supply, play an important role in determining helper effects and responses of aided dominant pairs. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-18T04:22:57.886163-05:
      DOI: 10.1111/jav.00783
  • Effects of avian malaria on male behaviour and female visitation in
           lekking Blue‐crowned Manakins
    • First page: 457
      Abstract: Avian malaria, the infection by blood parasites of the genus Plasmodium, can reduce host fitness not only through mortality, but also by impairing the expression of sexual selection traits. Although different studies highlight the association of parasitism with a decrease in host reproductive success, few studies have addressed the role of parasites in honest signalling by lekking species. Hence, it is still uncertain which fitness components are affected by parasites in these species. We investigated whether avian malaria is associated with a decrease in mating behaviour of male Blue‐crowned Manakins, Lepidothrix coronata, and whether it affects female visitation in leks of a population in the Central Amazon. Through behavioural observations, we estimated the rates of total male activity and social interaction, as well as the frequency of female visits at individual perches. We then examined if individuals were infected with Plasmodium spp. using molecular techniques. Avian malaria was associated with a decrease in male mating behaviour in each lek, and mating behaviour correlated with female visitation. Although rates of social interaction were not correlated with avian malaria among males, we observed that interacting with several individuals within a lek may be advantageous for males, as they also vocalized and displayed more, thus increasing their chances of being visited by females. Although female visitation was not associated with avian malaria in individuals or leks, it is still possible that female visitation is indirectly affected by avian malaria through the latter's effects on male activity. We suggest a role for male activity as an honest sexual signal for females. Thus, male display rate could be used by females as cue for the probability of a male being infected. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-01T05:51:46.857053-05:
      DOI: 10.1111/jav.00864
  • Individual repeatability in laying behaviour does not support the
           migratory carry‐over effect hypothesis of egg‐size dimorphism in
           Eudyptes penguins
    • Authors: Kyle W. Morrison
      First page: 466
      Abstract: Penguins of the genus Eudyptes are unique among birds in that their first‐laid A‐egg is 54–85% the mass of their second‐laid B‐egg. Although the degree of intra‐clutch egg‐size dimorphism varies greatly among the seven species of the genus, obligate brood reduction is typical of each, with most fledged chicks resulting from the larger B‐egg. Many authors have speculated upon why Eudyptes penguins have evolved and maintained a highly dimorphic 2‐egg clutch, and why it is the first‐laid egg that is so much smaller than the second, but only recently has a testable, proximate mechanism been proposed. In most species of Eudyptes penguins females appear to initiate egg‐formation at sea during return migration to breeding colonies. In macaroni penguins E. chrysolophus, females with a shorter pre‐laying interval ashore (and thus presumably greater overlap between migration and egg‐formation) lay more dimorphic eggs, suggesting a physiological conflict may constrain growth of the earlier‐initiated A‐egg. This migratory carry‐over effect hypothesis (MCEH) was tested in eastern rockhopper penguins E. chrysocome filholi on Campbell Island, New Zealand, by recording the arrival and lay dates, body sizes, and egg masses of transponder‐tagged females over two years. Females with longer pre‐laying intervals laid less dimorphic clutches, as predicted by the MCEH. However, repeated measures of individual females revealed that within‐individual variation in egg‐size dimorphism between years was unrelated to within‐individual variation in pre‐laying interval. Egg masses, and to a lesser extent egg‐size dimorphism, were highly repeatable traits related to body size and body mass. These results and a detailed consideration of the MCEH suggest that egg‐size dimorphism in Eudyptes penguins is unlikely to be caused by a migratory carry‐over effect. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-01T03:20:50.309271-05:
      DOI: 10.1111/jav.00740
  • The trade‐off between clutch size and egg mass in tree swallows
           (Tachycineta bicolor) is modulated by female body mass
    • First page: 500
      Abstract: Egg production is a costly component of reproduction for female birds in terms of energy expenditure and maternal investment. Because resources are typically limited, clutch size and egg mass are expected to be constrained, and this putative trade‐off between offspring number and size is at the core of life history theory. Nevertheless, empirical evidence for this trade‐off is equivocal at best, as individual heterogeneity in resource acquisition and allocation may hamper the detection of the negative correlation between egg number and mass within populations. Here, we investigated how female body mass and landscape composition influences clutch size, egg mass, and the relationship between these two traits. To do so, we fitted linear mixed models using data from tree swallows (Tachycineta bicolor) breeding in a network of 400 nestboxes located along a gradient of agricultural intensity between 2004 and 2011. Our dataset comprised 1463 broods for clutch sizes analyses and 4371 eggs (from 847 broods laid between 2005‐2008) for egg mass analyses. Our results showed that agricultural intensity negatively impacted clutch size, but not egg mass nor the relationship between these two traits. Female mass, on the other hand, modulated the trade‐off between clutch size and egg mass. For heavier females, both traits increased jointly, without evidence of a trade‐off. However, for lighter females, there was a clear negative relationship between clutch size and egg mass. This work shows that accounting for individual heterogeneity in body mass allows the detection of a clutch size/egg mass trade‐off that would have remained undetected otherwise. Identifying habitat and individual effects on resource allocation towards reproductive traits may help bridging the gap between predictions from theory and empirical evidence on life history trade‐offs. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-01T03:13:23.782462-05:
      DOI: 10.1111/jav.00725
  • Intermediate habitat associations by hybrids may facilitate genetic
           introgression in a songbird
    • Authors: Eric M. Wood; Sara E. Barker Swarthout, Wesley M. Hochachka, Jeffery L. Larkin, Ronald W. Rohrbaugh, Kenneth V. Rosenberg, Amanda D. Rodewald
      First page: 508
      Abstract: Hybridization or the interbreeding of genetically discrete populations or species can occur where ranges of genetically distinct units overlap. Golden‐winged Warblers (Vermivora chrysoptera), a species that has been in steady decline for decades, highlight the potential population‐level consequences of hybridization. A major factor implicated in their decline is hybridization with their sister species, the Blue‐winged Warbler (Vermivora cyanoptera), which has likely been exacerbated by historic and current land‐use practices. We examined habitat associations of Golden‐winged and Blue‐winged Warblers, phenotypic hybrids, and cryptic hybrids (i.e., mismatch between plumage phenotype and genotype as identified by mitochondrial DNA) in an area of relatively recent range overlap and hybridization in northern New York, USA. To explore the robustness of these results, we then compared the patterns from New York with habitat associations from the central Pennsylvanian Appalachian Mountains where Blue‐winged Warblers either do not occur or are in very low abundance, yet cryptic Golden‐winged Warbler hybrids are present. From 2008 to 2011, we captured 122 birds in New York and 28 in Pennsylvania and collected blood samples, which we used to determine maternal ancestry. For each bird captured, we measured territory‐level (50‐m radius circles) habitat, and later used remote‐sensing data to quantify habitat on the territories and in surrounding areas (100‐, 250‐, and 500‐m radius circles). In New York, Golden‐winged Warblers occupied structurally heterogeneous territories surrounded by homogeneously structured, contiguous deciduous forest, far from urban areas. Blue‐winged Warblers showed opposite associations, and hybrids' habitat associations were typically intermediate. In Pennsylvania, the habitat associations of Golden‐winged Warblers and their cryptic hybrids were remarkably similar to those in New York. These findings suggest that patterns of habitat occupancy by hybrids may promote contact with Golden‐winged Warblers and thus likely facilitate genetic introgression, even in areas where the parental species are not sympatric. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-18T04:29:08.411435-05:
      DOI: 10.1111/jav.00771
  • Experimental exposure to trace metals affects plumage bacterial community
           in the feral pigeon
    • Authors: M. Chatelain; A. Frantz, J. Gasparini, S. Leclaire
      First page: 521
      Abstract: Bacteria are fundamental associates of animals, and recent studies have highlighted their major role in host behaviour, immunity or reproductive investment. Thus, any environmental factor modifying bacterial community may affect host fitness. In birds, trace metals emitted by anthropogenic activities accumulate onto the plumage where they may alter bacterial community and ultimately affect bird fitness. Although trace metals are current major environmental issues in urban habitats, their effects on feather bacterial community have never been investigated. Here, we supplemented feral pigeons (Columba livia), an emblematic urban species, with zinc and/or lead in drinking and bath water. As expected, lead and zinc supplementations modified plumage bacterial community composition. Zinc decreased bacterial load, while lead decreased bacterial richness and the frequency of preening behaviour in birds, known to regulate feather bacteria. Our results demonstrate for the first time the effects of common urban trace metals on plumage bacterial community and shed light on one of the mechanisms by which trace metals can affect bird fitness. Further studies are now needed to investigate how this effect modulates avian life history traits known to depend on plumage bacterial community. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-01T05:51:25.747332-05:
      DOI: 10.1111/jav.00857
  • An experimental evaluation of the effects of geolocator design and
           attachment method on between‐year survival on Whinchats Saxicola rubetra
    • Authors: Emma Blackburn; Malcolm Burgess, Benedictus Freeman, Alice Risely, Arin Izang, Sam Ivande, Chris Hewson, Will Cresswell
      First page: 530
      Abstract: Data from location logging tags have revolutionised our understanding of migration ecology, but methods of tagging that do not compromise survival need to be identified. We compared resighting rates for 156 geolocator‐tagged and 316 colour ringed‐only Whinchats on their African wintering grounds after migration to and from Eastern Europe in two separate years. We experimentally varied both light stalk length (0, 5 and 10 mm) and harness material (elastic or non‐elastic nylon braid tied on, leg‐loop ‘Rappole’ harnesses) in the second year using a reasonably balanced design (all tags in the first year used an elastic harness and 10 mm light stalk). Tags weighed 0.63 g (0.01SE), representing 4.1 % of average body mass. There was no overall significant reduction in between‐year resighting rate (our proxy for survival) comparing tagged and untagged birds in either year. When comparing within tagged birds, however, using a tied harness significantly reduced resighting rate by 53 % on average compared to using an elastic harness (in all models), but stalk length effects were not statistically significant in any model considered. There was no strong evidence that the fit (relative tightness) or added tag mass affected survival, although tied tags were fitted more tightly later in the study, and birds fitted with tied tags later may have had lower survival. Overall, on a precautionary principle, deploying tags with non‐elastic tied harnesses should be avoided because the necessary fit, so as not to reduce survival, is time‐consuming to achieve and does not necessarily improve with experience. Geolocator tags of the recommended percentage of body mass fitted with elastic leg‐loop harnesses and with short light stalks can be used without survival effects in small long‐distance migrant birds. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-01T03:22:24.986858-05:
      DOI: 10.1111/jav.00871
  • Female collared flycatchers choose neighbouring and older extra‐pair
           partners from the pool of males around their nests
    • Authors: Anais Edme; Pavel Munclinger, Milos Krist
      First page: 552
      Abstract: Extra‐pair copulation is common among passerine birds. Females might engage in this behavior to obtain direct or indirect benefits. They may choose extra‐pair males with larger ornaments, especially if they are costly to produce. Here we studied extra‐pair paternity in the collared flycatcher. Genetic analysis allowed us to identify the presence or absence of extra‐pair young in the focal nests, and to identify extra‐pair fathers. We also identified potential males available as extra‐pair sires around the nests of females who had extra‐pair young. First, we tested the relationship between paternity in own nest and ornament size (wing patch and/or forehead patch), morphological traits and age of social males and females. Second, we compared the same suite of traits among social mates, extra‐pair males and all potential extra‐pair mates. Finally, we investigated the effect of the size of ornaments on the distance between the social nest and that of nest the extra‐pair father. Contrary to our prediction, males with larger ornaments and longer wings lost more paternity in their nests. We also found that early breeders lost less paternity in their nests. Extra‐pair males were older and had longer wings than social and potential extra‐pair males. Females mainly obtained extra‐pair mates near their nests but the distance did not vary according to ornamentation. These results could potentially be explained by differences in mate guarding strategy as older males may be more experienced in guarding their mate and attract other females more easily. More data about mate guarding and prospecting are needed to increase our understanding of mechanisms underlying the extra‐pair paternity in birds.
      PubDate: 2016-01-14T07:51:52.848313-05:
      DOI: 10.1111/jav.00839
  • Foraging behaviour and fuel accumulation of capital breeders during spring
           migration as derived from a combination of satellite‐ and ground‐based
    • First page: 563
      Abstract: The migration strategy of many capital breeders is to garner body stores along the flyway at distinct stopover sites. The rate at which they can fuel is likely to be strongly influenced by a range of factors, such as physiology, food availability, time available for foraging and perceived predation. We analysed the foraging behaviour and fuel accumulation of pink‐footed geese, an Arctic capital breeder, at their mid‐ flyway spring stopover site and evaluated to what extent their behaviour and fuelling were related to physiological and external factors and how it differed from other stopovers along the flyway. We found that fuel accumulation rates of geese at the mid‐flyway site were limited by habitat availability rather than by digestive constraints. However, as the time available for foraging increased over the stopover season, geese were able to keep constant fuelling rate. Putting this in perspective, geese increased their daily net energy intake along the flyway corresponding to the increase in time available for foraging. The net energy intake per hour of foraging remained the same. Geese showed differences in their reaction to predators/disturbance between the sites, taking higher risks particularly at the final stopover site. Hence, perceived predation along the flyway may force birds to postpone the final fuel accumulation to the last stopover along the flyway. Flexibility in behaviour appears to be an important trait to ensure fitness in this capital breeder. Our findings are based on a new, improved method for estimating fuel accumulation of animals foraging in heterogeneous landscapes based on data obtained from satellite telemetry and habitat specific intake rates. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-14T07:52:24.785351-05:
      DOI: 10.1111/jav.00899
  • A rare study from the wintering grounds provides insight into the costs of
           malaria infection for migratory birds
    • First page: 575
      Abstract: Malaria parasites can have strong effects on the population dynamics and evolution of migratory bird species. In many species, parasite transmission occurs on the wintering grounds, but studies to determine the consequences of infection have taken place during the breeding season, when malaria parasites circulate at chronic levels. We examined the predictors of malarial infections for great reed warblers during the northern winter in Africa, where active parasite transmission is thought to occur and naïve individuals experience acute infections. Counter to expectations, we found that winter infection intensities were lower than those encountered on the breeding grounds. One potential explanation is that reduced immune function during breeding allows parasites to persist at higher chronic intensities. We found no relationships between the incidence or intensity of infection on condition (as measured by scaled mass index, plasma metabolites, and feather corticosterone), spring migration departure dates, or home range sizes. We also tested a prediction of the Hamilton‐Zuk hypothesis and found that male ornament (song) quality was unrelated to parasitic infection status. Overall, our results provide the first evidence that long‐distance migrants captured on their wintering grounds are in the chronic stage of infection, and suggest that winter studies may fare no better than breeding studies at determining the costs of acute malarial infection for great reed warblers. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-14T07:52:08.420289-05:
      DOI: 10.1111/jav.00870
  • Cost of reproduction: a comparison of survival rates of breeding and
           non‐breeding male ortolan buntings
    • Authors: Svein Dale
      First page: 583
      Abstract: The cost of reproduction is expected to influence survival or future reproduction. Most previous studies have assessed cost of reproduction in relation to natural and experimental variation in number of offspring produced. The ortolan bunting (Emberiza hortulana) is a passerine bird species with biparental care, and the Norwegian population of the species has an extraordinarily skewed sex ratio with only about half of the males attracting a female, and therefore provides a rare opportunity to compare survival of males that have paired and bred with that of non‐breeders (unpaired males), which have not paid a cost of reproduction. Results showed that survival rates of paired (65.0%) and unpaired (64.2%) males did not differ. However, when comparisons were restricted to paired males that definitely had nestlings, their survival rate (76.8%) was significantly higher than that of unpaired males, and the same was the case when comparisons were further restricted to paired males that had offspring recruiting to the population the next year (76.8% survived). Males breeding successfully are likely to be a biased subset of high quality males. In analyses of a subset of males that had bred successfully when young, there was no difference in survival of paired and unpaired individuals when these males were older. In conclusion, breeding male ortolan buntings did not appear to pay a cost of reproduction in terms of reduced survival to the next year compared to non‐breeding males. These results may be explained by non‐breeding males also incurring extra costs during the breeding season, and that costs of reproduction are not shared equally among sexes in the ortolan bunting and other bird species with biparental care. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-21T02:26:10.331859-05:
      DOI: 10.1111/jav.00898
  • Comparing inferences of solar geolocation data against high‐precision
           GPS data: annual movements of a double‐tagged black‐tailed godwit
    • Authors: Eldar Rakhimberdiev; Nathan R. Senner, Mo A. Verhoeven, David W. Winkler, Willem Bouten, Theunis Piersma
      First page: 589
      Abstract: Annual routines of migratory birds inferred from archival solar geolocation devices have never before been confirmed using GPS technologies. A female black‐tailed godwit Limosa limosa limosa captured on the breeding grounds in The Netherlands in 2013 and recaptured in 2014 was outfitted with both an Intigeo geolocator and an UvA‐BiTS GPS‐tracker. The GPS positions show that, after its breeding season in 2013, the godwit flew 2035 km nonstop from The Netherlands to southern Spain. It then spent the entire nonbreeding season in the southern part of the Iberian Peninsula before returning to The Netherlands the following spring, stopping for 7 days in the delta of the Ebro River in Spain, and again for a day in central Belgium. To compare the geolocation and GPS data, we analysed the geolocation data with two open‐source software packages: one using a threshold method (GeoLight) and the other a template‐fit approach (FLightR). Estimates using GeoLight, on average, deviated from the individual's true position by 495.5 ± 1031.2 km (great circle distance with equinoxes excluded), while FLightR estimates deviated by 43.3 ± 51.5 km (great circle distance with equinoxes included). Arrival and departure schedules estimated by FLightR were within 12 hours of those determined by the GPS tracker, whereas GeoLight's estimates were less precise. For the analysed track, FLightR represents an improvement over GeoLight; if true for other species and conditions, FLightR will hopefully help establish more precise and accurate uses of geolocation data in tracking studies. To aid future improvements in the analysis of solar geolocation data, we also provide the GPS and geolocation data files together with our R scripts as supplementary material. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-14T07:52:41.136478-05:
      DOI: 10.1111/jav.00891
  • Arion slugs as nest predators of small passerine species – a review
    • Abstract: Arionid slugs have been reported to attack nestlings of some ground‐ or shrub‐nesting passerine birds, mainly in Europe. We review these reported cases and consider their effects. The slugs can cause grave or even fatal injuries to the nestlings. Surprisingly, no brood defence by the parents has been described. The information on the frequency of slug predation in bird populations is scanty, and the scale of the phenomenon is unknown. The expansion of the invasive Arion vulgaris Moquin‐Tandon, 1855 (synonymously A. lusitanicus or A. lusitanicus auct. non Mabille, 1868) in Europe may result in an increase of the negative influence of slugs on the breeding success of some passerines in the near future. This article is protected by copyright. All rights reserved.
  • Northern flickers only work when they have to: how individual traits,
           population size and landscape disturbances affect excavation rates of an
           ecosystem engineer
    • Abstract: Woodpeckers are considered ecosystem engineers because they excavate tree cavities which are used subsequently by many species of secondary cavity nesters for breeding. Woodpeckers have the choice of excavating a new hole or reusing an existing one, and this propensity to excavate (e) may affect community dynamics but has rarely been investigated. Using 18 years of data on a population of northern flickers Colaptes auratus, I tested six hypotheses to explain the propensity to excavate (e) in a landscape which experienced two types of disturbance: pine beetles and wildfires. Woodpecker age, breeding experience and mate retention had little influence on e which varied between 13‐39% annually and averaged 23% for 1843 first nests over the 18 years. Body size and body condition of males and females were not associated with e but rates of excavation declined seasonally, suggesting time rather than energy costs limited excavation effort. Reduced cavity availability mediated through high conspecific density coupled with wildfires triggered relatively high excavation rates, up to 39% but e decreased to baseline levels three years after the landscape disturbances. Nearly 2/3 of males did not excavate in their lifetime but apparently, e is great enough to balance the average rate of cavity tree loss in this forest which is 11% annually. Excavation propensity in flickers is flexible, but the birds reduce their work levels if there is a surplus of holes available. This article is protected by copyright. All rights reserved.
  • SpotEgg: An image‐processing tool for automatised analysis of
           colouration and spottiness
    • Abstract: Colouration and patterning are widespread amongst organisms. Regarding avian eggs, colouration (reflectances) has been previously measured using spectrometers whereas spottiness has been determined using human‐based scoring methods or by applying global thresholding over the luminance channel on photographs. However, the availability of powerful computers and digital image‐processing algorithms and software offers new possibilities to develop systematised, automatable, and accurate methods to characterise visual information in eggs. Here, we provide a computing infrastructure (library of functions and a Graphical User Interface) for eggshell colouration and spottiness analysis called SpotEgg, which runs over MATLAB. Compared to previous methods, our method offers four novelties for eggshell visual analysis. First, we have developed a standardised non‐human biased method to determine spottiness. Spottiness determination is based on four parameters that allow direct comparisons between studies and may improve results when relating colouration and patterning to pigment extraction. Second, researcher time devoted to routine tasks is remarkably reduced thanks to the incorporation of image‐processing techniques that automatically detect the colour reference chart and egg‐like shapes in the scene. Third, SpotEgg reduces the errors in colour estimation through the eggshell that are created by the different angles of view subtended from different parts of the eggshell and the optical centre of the camera. Fourth, SpotEgg runs automatic Fractal Dimension analysis (a measure of how the details in a pattern change with the scale at which this pattern is measured) of the spots pattern in case researchers want to relate other measurements with this special spatial pattern. Finally, although initially conceived for eggshell analysis, SpotEgg can also be applied in images containing objects different from eggs as feathers, frogs, insects, etc., since it allows the user to manually draw any region to be analysed making this tool useful not only for oologist but also for other evolutionary biologists. This article is protected by copyright. All rights reserved.
  • Plasticity in incubation behavior and shading by king rails (Rallus
           elegans) in response to temperature
    • Abstract: King rails experience a wide range of temperatures during the course of the breeding season throughout their rapidly contracting geographic range. Incubating parent birds are adapted to keep their eggs within a temperature range appropriate for embryo development, but king rail clutches are at risk of exceeding lethal temperatures in the latter half of the nesting season. We investigated whether behavioral plasticity during incubation enables parents to maintain clutch temperature within tolerable limits for embryo development. Video revealed that king rail parents interrupted incubation to stand above and shade their eggs. We tested the hypothesis that the onset of shading was a direct response to ambient temperature (adaptive plasticity). We monitored clutch temperature directly by experimentally adding into clutches a model egg embedded with a programmable iButton. We measured ambient temperature at the nest site simultaneously. Parents spent proportionately more time shading and less time incubating their eggs at higher ambient temperatures. Shading may primarily function in cooling the parent. The frequency and duration of shading bouts were significantly greater at higher ambient temperatures. Parents also took more frequent but shorter recesses in hotter conditions. Diurnal recesses exposed eggs to direct sunlight, and the highest clutch temperatures were recorded under these conditions. Complete hatching failure in at least one nest was attributable to high clutch temperature for an extended period. Because mean ambient temperature increases throughout the breeding season, we investigated seasonal patterns in onset of incubation and its effect on hatching rate. Later in the season, parents tended to initiate incubation earlier, and hatching asynchrony increased significantly. Together these results suggest that breeding king rails may be constrained in their ability to cope with sustained high temperatures should seasonal averages continue to rise as predicted. This article is protected by copyright. All rights reserved.
  • A complete molecular phylogeny of Claravis confirms its paraphyly within
           small New World ground‐doves (Aves: Peristerinae) and implies multiple
           plumage state transitions
    • Abstract: The three species in the genus Claravis (Aves: Peristerinae) are unique among members of the small New World ground‐dove clade. All three species inhabit forested areas rather than open scrubby habitat, and exhibit obvious sexual dichromatism. However, the phylogenetic relationships within Claravis remain unknown. The only molecular phylogenetic study to include more than one species of Claravis indicated the genus is paraphyletic. Here we include molecular data from all three Claravis species, including sequences from a museum skin of the previously unsampled Claravis geoffroyi (purple‐winged ground‐dove). Using both mitochondrial and nuclear loci, we estimate phylogenies and divergence times for the small New World ground‐dove clade. We also use ancestral state reconstruction methods to infer the evolution of male blue plumage (and thus sexual dimorphism) in the clade. As in the previous study we recover Claravis as a paraphyletic group, but with Claravis geoffroyi as the sister species to Claravis mondetoura (maroon‐chested ground‐dove). This result has important implications for the evolutionary history of the small New World ground‐dove clade. In particular, we recover multiple independent transitions between the monomorphic and dimorphic plumage states, which perhaps indicates sexual dimorphism arose twice in the group. This article is protected by copyright. All rights reserved.
  • Rapid mobilization of abdominal fat in migrating eared grebes
    • Abstract: Eared grebes (Podiceps nigricollis), like shorebirds and other long‐distance migrants, lay down large amounts of fat to power their journeys. To investigate the pattern of how fat and soft tissue might be mobilized, we used grebes killed in migration and applied Computed Tomography to reconstruct how stores in the chest, thorax, and abdomen were reduced as body weight decreased. Fat and soft tissue were each mobilized at a constant rate through the entire migration. Fat stores in birds embarking on migration were greater in the abdomen than thorax than chest. In contrast to previous studies indicating that abdominal fat was mobilized first, we found that fat from all areas was mobilized concurrently, but that abdominal fat was catabolized at a greater rate. We suggest why this pattern might be advantageous, consider whether inter‐depot differences in fat composition might be involved, and note possible energetic consequences. Whether our findings pertain to other obese or long distance migrants remains to be determined. This article is protected by copyright. All rights reserved.
  • Tick infestation of chicks in a seabird colony varies with local breeding
           synchrony, local nest density and habitat structure
    • Abstract: Parasites are a major risk for group‐living animals and seabirds are notoriously susceptible to ectoparasite infestations because they commonly nest in dense colonies. Ticks parasitize seabirds across all biogeographical regions and they can be particularly harmful to nestlings, but the ecological factors that affect their transmission to chicks are little studied and poorly understood. Here we show that abundance of tick larvae in blue‐footed booby (Sula nebouxii) broods varies with local nest synchrony and density, and also with habitat structure: abundance increased with local breeding synchrony, was linearly and quadratically related to local nest density, and was highest toward the southern end of the study area which has suitable (boulder‐rich) habitat for ticks. Also, with increasing chick age infestation first increased and then declined. The results of this study highlight how local physical and social environmental factors influence infestation of seabird nestlings by ticks. This article is protected by copyright. All rights reserved.
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