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  Subjects -> BIOLOGY (Total: 2985 journals)
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BIOLOGY (1423 journals)            First | 1 2 3 4 5 6 7 8 | Last

Showing 1201 - 1400 of 1720 Journals sorted alphabetically
Redox Biology     Open Access   (Followers: 1)
Redox Report     Hybrid Journal  
Regeneration     Open Access   (Followers: 2)
Regulatory Peptides     Hybrid Journal   (Followers: 9)
Reinwardtia : A Journal on Taxonomy Botany, Plant Sociology and Ecology     Open Access  
Reports in Parasitology     Open Access   (Followers: 2)
Reports on Mathematical Physics     Full-text available via subscription   (Followers: 1)
Reports on Progress in Physics     Full-text available via subscription   (Followers: 3)
Reproductive Biology     Full-text available via subscription   (Followers: 1)
Reproductive Biology Insights     Open Access   (Followers: 2)
Reproductive Biomedicine & Society Online     Open Access  
Reproductive Toxicology     Hybrid Journal   (Followers: 14)
Research & Reviews : Journal of Computational Biology     Full-text available via subscription   (Followers: 4)
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: 11)
Research Journal of Parasitology     Open Access   (Followers: 3)
Research Journal of Seed Science     Open Access   (Followers: 3)
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: 32)
Reviews of Modern Physics     Full-text available via subscription   (Followers: 28)
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 Investigaciones Altoandinas - Journal of High Andean Research     Open Access  
Revista de la Ciencia del Suelo y Nutricion Vegetal     Open Access  
Revista de Protección Vegetal     Open Access  
Revista Eletrônica TECCEN     Open Access  
Revista Fitotecnia Mexicana     Open Access  
Revista Iberoamericana de Bioética     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: 4)
Rice Science     Open Access   (Followers: 2)
Risk Analysis     Hybrid Journal   (Followers: 35)
RNA     Hybrid Journal   (Followers: 9)
RNA & Disease     Open Access   (Followers: 1)
RNA Biology     Full-text available via subscription   (Followers: 4)
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   (Followers: 1)
Rwanda Journal     Full-text available via subscription  
Saudi Journal of Biological Sciences     Open Access   (Followers: 2)
Science and Engineering Ethics     Hybrid Journal   (Followers: 9)
Science Bulletin     Hybrid Journal  
Science China Life Sciences     Open Access  
Science Signaling     Full-text available via subscription   (Followers: 21)
Science Technology & Society     Hybrid Journal   (Followers: 4)
Scientific Journal of Biological Sciences     Open Access   (Followers: 1)
Scientific Papers Animal Science and Biotechnologies     Open Access  
Scientific Reports     Open Access   (Followers: 45)
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: 2)
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   (Followers: 1)
Seminars in Cancer Biology     Hybrid Journal   (Followers: 3)
Seminars in Cell & Developmental Biology     Hybrid Journal   (Followers: 6)
Seminars in Hematology     Hybrid Journal   (Followers: 11)
Sensing and Bio-Sensing Research     Open Access  
Sensors     Open Access   (Followers: 16)
Sexual Development     Full-text available via subscription   (Followers: 2)
Sierra Leone Journal of Biomedical Research     Open Access  
Signal Transduction and Targeted Therapy     Open Access  
Signal Transduction Insights     Open Access   (Followers: 2)
Simbiosis : Journal of Biological Sciences     Open Access  
SINET : Ethiopian Journal of Science     Open Access   (Followers: 6)
Small     Hybrid Journal   (Followers: 11)
Small GTPases     Full-text available via subscription   (Followers: 1)
Social and Natural Sciences Journal     Open Access  
Sociobiology     Open Access  
Somatic Cell and Molecular Genetics     Hybrid Journal   (Followers: 2)
Somatosensory and Motor Research     Hybrid Journal   (Followers: 1)
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: 2)
South Asian Journal of Experimental Biology     Open Access  
South Australian Naturalist, The     Full-text available via subscription  
Spatial Vision     Hybrid Journal   (Followers: 2)
Sri Lankan Journal of Biology     Open Access  
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: 5)
Stem Cell Discovery     Open Access   (Followers: 4)
Stem Cell Epigenetics     Open Access   (Followers: 3)
Stem Cell Reports     Open Access   (Followers: 11)
Stem Cell Research     Open Access   (Followers: 15)
Stem Cell Reviews and Reports     Hybrid Journal   (Followers: 8)
Stem Cells     Hybrid Journal   (Followers: 8)
Stem Cells and Cloning: Advances and Applications     Open Access   (Followers: 2)
Stem Cells International     Open Access   (Followers: 2)
Steroids     Hybrid Journal  
Studies in Mycology     Open Access   (Followers: 2)
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: 13)
Sustainability : The Journal of Record     Hybrid Journal   (Followers: 6)
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: 13)
Systematics and Biodiversity     Hybrid Journal   (Followers: 10)
Systems and Synthetic Biology     Hybrid Journal   (Followers: 11)
Systems Biology in Reproductive Medicine     Hybrid Journal  
Taprobanica : The Journal of Asian Biodiversity     Open Access  
Taxon     Full-text available via subscription   (Followers: 5)
Telomere and Telomerase     Open Access  
Terrestrial Arthropod Reviews     Hybrid Journal   (Followers: 1)
The Anatomical Record : Advances in Integrative Anatomy and Evolutionary Biology     Hybrid Journal   (Followers: 3)
The Botulinum J.     Hybrid Journal  
The Breast Journal     Hybrid Journal   (Followers: 10)
The Bryologist     Full-text available via subscription   (Followers: 8)
The Cerebellum     Hybrid Journal   (Followers: 2)
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: 2)
The FASEB Journal     Full-text available via subscription   (Followers: 24)
The Herpetological Journal     Full-text available via subscription   (Followers: 7)
The International Journal of Advanced Manufacturing Technology     Hybrid Journal   (Followers: 6)
The Journal of Technology Transfer     Hybrid Journal   (Followers: 7)
The Knee     Hybrid Journal   (Followers: 14)
The Nucleus     Hybrid Journal   (Followers: 1)
The Physics of Metals and Metallography     Hybrid Journal   (Followers: 16)
The Plant Cell     Full-text available via subscription   (Followers: 26)
The Protein Journal     Hybrid Journal   (Followers: 8)
Theoretical Biology and Medical Modelling     Open Access   (Followers: 2)
Theoretical Population Biology     Hybrid Journal   (Followers: 8)
Tissue and Cell     Hybrid Journal   (Followers: 2)
Tissue Engineering and Regenerative Medicine     Hybrid Journal   (Followers: 10)
Tissue Engineering Part A     Hybrid Journal   (Followers: 10)
Tissue Engineering Part B: Reviews     Hybrid Journal   (Followers: 8)
Tissue Engineering Part C: Methods     Hybrid Journal   (Followers: 8)
Toxicology in Vitro     Hybrid Journal   (Followers: 11)
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: 10)
Transportation Planning and Technology     Hybrid Journal   (Followers: 8)
Tree Genetics & Genomes     Hybrid Journal   (Followers: 3)
Tree-Ring Research     Full-text available via subscription  
Trees     Hybrid Journal   (Followers: 5)
Trends in Bacteriology     Open Access   (Followers: 3)
Trends in Bioinformatics     Open Access   (Followers: 21)
Trends in Biotechnology     Full-text available via subscription   (Followers: 131)
Trends in Cell Biology     Full-text available via subscription   (Followers: 33)
Trends in Evolutionary Biology     Open Access   (Followers: 13)
Trends in Microbiology     Full-text available via subscription   (Followers: 36)
Trends in Molecular Sciences     Open Access   (Followers: 5)
Trends in Parasitology     Full-text available via subscription   (Followers: 9)
Trends in Plant Science     Full-text available via subscription   (Followers: 25)
Trends in Vector Research and Parasitology     Open Access  
Tropical Freshwater Biology     Full-text available via subscription  
Tumor Biology     Hybrid Journal   (Followers: 3)
Tumor Microenvironment and Therapy     Open Access  
Tunnelling and Underground Space Technology     Hybrid Journal   (Followers: 7)
Turtle and Tortoise Newsletter     Full-text available via subscription   (Followers: 1)
Ukrainian Journal of Ecology     Open Access   (Followers: 1)
Ultrasound in Medicine & Biology     Full-text available via subscription   (Followers: 8)
Uniciencia     Open Access  
Universal Journal of Biomedical Engineering     Open Access  
Unnes Journal of Biology Education     Open Access   (Followers: 1)
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   (Followers: 1)
Virologica Sinica     Hybrid Journal  
Virology Journal     Open Access   (Followers: 6)
Virulence     Full-text available via subscription   (Followers: 1)
Virus Evolution     Open Access   (Followers: 1)

  First | 1 2 3 4 5 6 7 8 | Last

Journal Cover Journal of Avian Biology
  [SJR: 1.296]   [H-I: 59]   [24 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  [1583 journals]
  • The evolutionary origin of variation in song length and frequency in the
           avian family Cettiidae
    • Authors: Chentao Wei; Trevor D. Price, Jiayu Liu, Per Alström, Yanyun Zhang
      Abstract: Aspects of bird song have been shown to correlate with morphological and ecological features, including beak and body size, and habitat. Here we study evolution of song length and song frequency among 30 species belonging to the Cettiidae. Frequency is negatively correlated with body size, and song length increases with latitude. Although migration distance correlates with latitude, the association of song length with latitude is only present within the non-migratory species, implying the association is not a consequence of migration. We place these correlations in a historical framework to show that the body size-frequency association arose early in the group, but the latitude-song length association is more evolutionarily labile. We suggest that latitudinal correlates of song length may reflect increased importance of sexual selection by female choice.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-12T04:26:15.186599-05:
      DOI: 10.1111/jav.01366
       
  • Does habitat specialization shape the evolutionary potential of wild bird
           populations'
    • Authors: Martinossi-Allibert I; Clavel J, Ducatez S, Le Viol I, Teplitsky C
      Abstract: Because specialist species evolved in more temporally and spatially homogeneous environments than generalist species, they are supposed to experience less fluctuating selection. For this reason, we expect specialists to show lower overall genetic variation as compared to generalists. We also expect populations from specialist species to be smaller and more fragmented, with lower neutral genetic diversity. We tested these hypotheses by investigating patterns of genetic diversity along a habitat specialization gradient in wild birds, based on estimates of heritability, coefficients of variation of additive genetic variance, and heterozygosity available in the literature. We found no significant effect of habitat specialization on any of the quantitative genetic estimators but generalists had higher heterozygosity. This effect was mainly a consequence of the larger population size of generalists. Our results suggest that evolutionary potential does not differ at the population level between generalist and specialist species, but the trend observed in heterozygosity levels and population sizes may explain their difference in susceptibility to extinction.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-12T04:26:14.172697-05:
      DOI: 10.1111/jav.01011
       
  • Survivorship across the annual cycle of a migratory passerine, the willow
           flycatcher
    • Authors: Eben H. Paxton; Scott L. Durst, Mark K. Sogge, Thomas J. Koronkiewicz, Kristina L. Paxton
      Abstract: Annual survivorship in migratory birds is a product of survival across the different periods of the annual cycle (i.e., breeding, wintering, and migration), and may vary substantially among these periods. Determining which periods have the highest mortality, and thus are potentially limiting a population, is important especially for species of conservation concern. To estimate survival probabilities of the willow flycatcher (Empidonax traillii) in each of the different periods, we combined demographic data from a 10-year breeding season study with that from a 5-year wintering grounds study. Estimates of annual apparent survival for breeding and wintering periods were nearly identical (65-66%), as were estimates of monthly apparent survival for both breeding and wintering stationary periods (98-99%). Because flycatchers spend at least half the year on the wintering grounds, overall apparent survivorship was lower (88%) on the wintering grounds than on the breeding grounds (97%). The migratory period had the highest mortality rate, accounting for 62% of the estimated annual mortality even though it comprises only one quarter or less of the annual cycle. The migratory period in the willow flycatcher and many other neotropical migrants is poorly understood, and further research is needed to identify sources of mortality during this crucial period.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-12T04:26:12.059012-05:
      DOI: 10.1111/jav.01371
       
  • Safety first: terrestrial predators drive selection of highly specific
           nesting sites in colonial-breeding birds
    • Authors: Daniel J. D. Natusch; Jessica A. Lyons, Richard Shine
      Abstract: Nesting is a critical yet hazardous life stage for many birds. For colonial-breeding birds, the conspicuousness of the colony to predators suggests immense pressure to select optimal colonial nesting sites. But what drives selection of those sites' As with solitary nesting birds, reducing access by predators may be the single most important factor. If so, knowledge of the predators involved and the attributes of different potential colony sites can allow us to predict the features that make a site especially safe. We examined the attributes of trees used by breeding colonies of metallic starlings (Aplonis metallica) in tropical Australia, and experimentally tested if those attributes prevented nest access by predatory snakes. Our surveys confirmed that tree choice by starling nesting colonies is highly non-random, with all colonies located in tall trees in rainforest clearings, with no low branches and smooth bark. Experimental tests demonstrated that a predatory snake's climbing ability depends upon bark rugosity, and that colony access by snakes depends on tree attributes such as bark rugosity and canopy connectivity. Our study confirms that colonial-nesting starlings select colony sites that provide a safe refuge from predation. Intense predation pressure may have driven the evolution of stringent breeding habitat criteria in many other species of colonial-breeding birds.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-07T00:45:27.650855-05:
      DOI: 10.1111/jav.01380
       
  • Altered breeding biology of the European blackbird under artificial light
           at night
    • Authors: Anja Russ; Terézia Lučeničová, Reinhard Klenke
      Abstract: Artificial light at night (LAN) has become a stressor of global extent. Previous work has highlighted the high potential of LAN to interfere with annual and diel rhythms of seasonal organisms as well as to affect interactions at the community level. However, our understanding how LAN induced alterations of activity and breeding cycles affect the reproductive outcome and fitness of the birds is still limited. Here, we focus on the effects of night time illumination on the breeding biology of urban European blackbirds (Turdus merula). Our results indicate that blackbirds prefer illuminated nest sites and advance their date of clutch initiation by 6 days per 1 lux of night time illumination. Furthermore, daily nest survival rates increased with increasing LAN although this effect was most pronounced for the transition from dark to slightly illuminated sites. We suggest that blackbirds breeding under low artificial night light conditions benefit from the LAN-avoidance of their major predators (nocturnal) whereas predominant predators of blackbirds nesting in the city centre are diurnal and are, thus, not affected by LAN. Hence, it seems likely that both direct effects of LAN on the timing of reproduction as well as indirect effects on interspecific interactions might contribute to the observed changes in the breeding biology of European blackbirds.This study emphasizes the diverse ecological effects of the night time illumination which are – in its complexity – still poorly understood.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-05T05:40:37.511881-05:
      DOI: 10.1111/jav.01210
       
  • Contributions of feather microstructure to eider down insulation
           properties
    • Authors: Liliana D'Alba; Thomas Holm Carlsen, Árni Ásgeirsson, Matthew. D Shawkey, Jón Einar Jónsson
      Abstract: Insulation is an essential component of nest structure that helps provide incubation requirements for birds. Many species of waterfowl breed in high latitudes where rapid heat loss can necessitate a high energetic input from parents and use down feathers to line their nests. Common Eider (Somateria mollissima) nest down has exceptional insulating properties but the microstructural mechanisms behind the feather properties have not been thoroughly examined.Here, we hypothesized that insulating properties of nest down are correlated to down feather (plumule) microstructure. We tested the thermal efficiency (fill power) and cohesion of plumules from nests of two Icelandic colonies of wild Common Eiders and compared them to properties of plumules of wild Greylag Goose (Anser anser). We then used electron microscopy to examine the morphological basis of feather insulating properties. We found that Greylag Goose down has higher fill power (i.e. traps more air) but much lower cohesion (i.e. less prone to stick together) compared to Common Eider down. These differences were related to interspecific variation in feather microstructure. Down cohesion increased with the number of barbule microstructures (prongs) that create strong points of contact among feathers. Eider down feathers also had longer barbules than Greylag Goose down feathers, likely increasing their air-trapping capacity. Feather properties of these two species might reflect the demands of their contrasting evolutionary history. In Greylag Goose, a temperate, terrestrial species, plumule microstructure may optimize heat trapping. In Common Eiders, a diving duck that nests in arctic and subarctic waters, plumule structure may have evolved to maximize cohesion over thermal insulation, which would both reduce buoyancy during their foraging dives and enable nest down to withstand strong arctic winds.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-05T05:40:36.304586-05:
      DOI: 10.1111/jav.01294
       
  • Individuality in northern lapwing migration and its link to timing of
           breeding
    • Authors: Götz Eichhorn; Willem Bil, James W. Fox
      Abstract: We tracked eight adult northern lapwings, Vanellus vanellus, (six females and two males) from a Dutch breeding colony by light-level geolocation year-round, three of them for multiple years. We show that birds breeding virtually next to each other may choose widely separated wintering grounds, stretching from nearby the colony west towards the UK and Ireland, and southwest through France into Iberia and Morocco. However, individual lapwings appeared relatively faithful to a chosen wintering area, and timing of outward and homeward migration can be highly consistent between years. Movements of migratory individuals were usually direct and fast, with some birds covering distances of approximately 2000 km within 2 to 4 days of travel. The two males wintered closest and returned earliest to the breeding colony. The female lapwings returned well before the onset of breeding, spending a pre-laying period of 19 to 54 days in the wider breeding area. Despite the potential for high migration speeds, the duration that birds were absent from the breeding area increased with distance to wintering areas, a pattern which was mainly driven by an earlier outward migration of birds heading for more distant wintering grounds. Moreover, females that overwintered closer to colony bred earlier. A large variation in migration strategies found even within a single breeding colony has likely supported the species’ responsiveness to recent climate change as evidenced by a shortened migration distance and an advanced timing of reproduction in Dutch lapwings since the middle of the 20th century.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-05T05:40:34.23809-05:0
      DOI: 10.1111/jav.01374
       
  • Characterising demographic contributions to observed population change in
           a declining migrant bird
    • Authors: Jennifer A. Border; Ian G. Henderson, Ian R. Hartley
      Abstract: Populations of Afro-Palearctic migrant birds have shown severe declines in recent decades. To identify the causes of these declines, accurate measures of both demographic rates (seasonal productivity, apparent survival, immigration) and environmental parameters will allow conservation and research actions to be targeted effectively. We used detailed observations of marked breeding birds from a ‘stronghold’ population of whinchats Saxicola rubetra in England (stable against the declining European trend) to reveal both on-site and external mechanisms that contribute to population change. From field data, a population model was developed based on demographic rates from 2011 to 2014. Observed population trends were compared to the predicted population trends to assess model-accuracy and the influence of outside factors, such as immigration. The sensitivity of the projected population growth rate to relative change in each demographic rate was also explored. Against expectations of high productivity, we identified low seasonal breeding success due to nocturnal predation and low apparent first-year survival, which led to a projected population growth rate (') of 0.818, indicating a declining trend. However, this trend was not reflected in the census counts, suggesting that high immigration was probably responsible for buffering against this decline. Elasticity analysis indicated ' was most sensitive to changes in adult survival but with covariance between demographic rates accounted for, ' was most sensitive to changes in productivity. Our study demonstrates that high quality breeding habitat can buffer against population decline but high immigration and low productivity will expose even such stronghold populations to potential decline or abandonment if either factor is unsustainable. First-year survival also appeared low, however this result is potentially confounded by high natal dispersal. First-year survival and/or dispersal remains a significant knowledge gap that potentially undermines local solutions aimed at counteracting low productivity.This article is protected by copyright. All rights reserved.
      PubDate: 2017-04-05T05:40:32.205494-05:
      DOI: 10.1111/jav.01305
       
  • Preparation for flight: pre-fledging exercise time is correlated with
           growth and fledging age in burrow-nesting seabirds
    • Authors: Ken Yoda; Tatsuya Shiozaki, Masaki Shirai, Sakiko Matsumoto, Maki Yamamoto
      Abstract: Chicks of many burrow-nesting seabirds are known to repeatedly emerge from their nests (these trips being termed ‘excursions’) and exercise their wings prior to fledging, but this behavior is poorly documented in the literature, and thus the relationship between growth and exercise remains unclear. Here, we used infrared video cameras placed in front of streaked shearwater Calonectris leucomelas nests during the chick-emergence period to examine correlations between chick excursions and parameters known to be important for juvenile survival after fledging. In addition, we also attached acceleration-temperature loggers to several chicks in order to evaluate the relationship between excursion time and time spent exercising the wing muscles (i.e. flapping). Chicks that undertook longer excursions exhibited more rapid increases in wing length and larger body masses at fledging, and also fledged earlier. Correlations between fitness-related parameters and excursion time indicate that excursions during the emergence period might offer insights into the various relationships between growth and behavior and/or the mechanisms underlying offspring survival following fledging.
      PubDate: 2017-03-15T06:40:33.41229-05:0
      DOI: 10.1111/jav.01186
       
  • Variable drivers of primary versus secondary nesting; density-dependence
           and drought effects on greater sage-grouse
    • Authors: Erik J. Blomberg; Daniel Gibson, Michael T. Atamian, James S. Sedinger
      Abstract: Organisms seek to maximize fitness by balancing reproductive allocations against mortality risk, given selection pressures inherent to the environment. However, environmental conditions are often dynamic and unpredictable, which complicates the ability to achieve such a balance, and may require reproductive adjustments depending on prevailing conditions. We evaluated the effects of density-dependent, density-independent (drought), and individual (age, body condition) factors on nesting decisions of female greater sage-grouse in the American Great Basin. We obtained relocations and recorded reproductive histories from 287 radio-marked females over a period of 10 yr, and applied these data to a multi-state model that estimated probabilities of initiating a first nest (primary nesting rate) or a second nest, given loss of a first (secondary nesting rate). This approach allowed us to evaluate the relative association between nesting rates and covariates while accounting for imperfect detection of nests. Sage-grouse primary and secondary nesting were influenced differently by density dependence and drought. Primary nesting was high and relatively constant among years despite variable drought conditions, but was negatively associated with population size (density dependence). Secondary nesting was lower and more variable compared to primary nesting, was similarly influenced by density-dependence, and was also sensitive to drought conditions. Females known to initiate second nests were in better body condition than females that only initiated first nests, and females of intermediate age had higher primary nesting rates, whereas secondary nesting was unaffected by age. Our results suggest that females were more flexible and responded more readily to changing conditions when allocating resources to second nests. These results are consistent with patterns that have been demonstrated for female allocation to clutch size in this system, and suggest that when conditions are poor second nests reflect a tipping point where reproductive costs (increased mortality) outweigh benefits (offspring reproductive value).
      PubDate: 2017-03-15T06:40:25.501831-05:
      DOI: 10.1111/jav.00988
       
  • Songbirds are resilient to hurricane disturbed habitats during spring
           migration
    • Authors: Emily J. Lain; Theodore J. Zenzal, Frank R. Moore, Wylie C. Barrow, Robert H. Diehl
      Abstract: The Gulf of Mexico is a conspicuous feature of the Neotropical–Nearctic bird migration system. Traveling long distances across ecological barriers comes with considerable risks, and mortality associated with intercontinental migration may be substantial, including that caused by storms or other adverse weather events. However, little, if anything, is known about how migratory birds respond to disturbance-induced changes in stopover habitat. Isolated, forested cheniere habitat along the northern coast of the Gulf of Mexico often concentrate migrants, during weather conditions unfavorable for northward movement or when birds are energetically stressed. We expected hurricane induced degradation of this habitat to negatively affect the abundance, propensity to stopover, and fueling trends of songbirds that stopover in coastal habitat. We used spring banding data collected in coastal Louisiana to compare migrant abundance and fueling trends before (1993–1996 and 1998–2005) and after hurricanes Rita (2006) and Ike (2009). We also characterized changes in vegetative structure before (1995) and after (2010) the hurricanes. The hurricanes caused dramatic changes to the vegetative structure, which likely decreased resources. Surprisingly, abundance, propensity to stopover, and fueling trends of most migrant species were not influenced by hurricane disturbance. Our results suggest that: 1) the function of chenieres as a refuge for migrants after completing a trans-Gulf flight may not have changed despite significant changes to habitat and decreases in resource availability, and 2) that most migrants may be able to cope with habitat disturbance during stopover. The fact that migrants use disturbed habitat points to their conservation value along the northern coast of the Gulf of Mexico.
      PubDate: 2017-03-15T06:35:29.479386-05:
      DOI: 10.1111/jav.01215
       
  • A comparative study of insect abundance and reproductive success of barn
           swallows Hirundo rustica in two urban habitats
    • Authors: Peter Györkös Teglhøj
      Abstract: Few studies have quantified the relative reproductive success of passerines in urban habitats. I studied food availability and reproductive success of barn swallows Hirundo rustica in two urban habitats during 2012–2015. Barn swallows breeding in the town center experienced lower insect densities than those in the town periphery. Lower food availability resulted in reduced feeding rates per capita, lower nestling body mass, longer nestling periods, longer inter-clutch intervals, fewer first and second brood fledglings and a lower total number of fledglings produced during the breeding season in comparison to barn swallows breeding in the town periphery. I hypothesize that the lower intra-specific competition for nest sites and fitness advantages linked to the solitary breeding in urban habitats balanced the apparent costs of reproduction in more urbanized habitats.
      PubDate: 2017-03-15T06:30:25.785001-05:
      DOI: 10.1111/jav.01086
       
  • Early arrival is not associated with more extra-pair fertilizations in a
           long-distance migratory bird
    • Authors: Barbara M. Tomotani; Ezra Caglar, Iván de la Hera, A. Christa Mateman, Marcel E. Visser
      Abstract: When assessing the benefits of early arrival date of migratory birds, a hidden and often ignored component of males’ fitness is the higher chance of early-arriving birds to obtain extra-pair fertilizations. Here we investigated how extra-pair paternity might affect the relationship between male arrival date and number of fertilizations in a model study system, the European pied flycatcher Ficedula hypoleuca. For this purpose, we sampled and genotyped breeding pairs, unpaired males and offspring (including embryos from unhatched eggs when possible) of a Dutch pied flycatcher population. Detailed information on arrival date of males, egg laying date of their social mates and nest success was also recorded. Early-arriving males had early-laying females and males with early-laying females had a higher probability of siring extra-pair eggs and obtain more fertilizations. However, male arrival date alone did not correlate with the probability to gain extra-pair paternity and neither to the amount of fertilized eggs. Both early- and late-arriving males had a higher probability of losing paternity in their own nest compared to birds with an intermediate arrival date. Finally, late-arriving males were more likely to remain unpaired but, interestingly, a few of these birds obtained paternity via extra-pair copulations. Because earlier arrival date did not lead to more extra-pair fertilizations and because such relationship seems to be driven mainly by the female's laying date, we conclude that the contribution of extra-pair paternity to the overall fitness benefits of early male arrival date is relatively small.
      PubDate: 2017-03-15T06:25:28.615302-05:
      DOI: 10.1111/jav.01317
       
  • Breeding synchrony and extrapair paternity in a species with alternative
           reproductive strategies
    • Authors: Melissa Grunst; Andrea S. Grunst, Rusty A. Gonser, Elaina M. Tuttle
      Abstract: Breeding synchrony may affect the tradeoff between pursuing multiple mates and avoiding paternity loss, translating into differences in the rate of extrapair paternity (EPP). However, diverse empirical relationships between breeding synchrony and EPP remain challenging to explain. We examined whether the relationship between breeding synchrony and EPP varied with male morph, age, body size, or breeding density in the white-throated sparrow (Zonotrichia albicollis). In this species, males of two genetically determined morphs pursue alternative mating strategies. Breeding synchrony positively correlated with EPP within polygamous white morph males, which have high rates of EPP and cuckoldry, but was unrelated to EPP within tan morph males, which prioritize mate guarding and paternal care. As previously reported, males that gained EPP were primarily white males. Males gained EPP more often than expected by chance during their mate's fertile period and on neighboring territories. Since extrapair copulation appears primarily male-driven in this species, these results indicate that white males focus extra-pair mating effort during periods of high synchrony and during their mates’ fertile periods, even at the expense of paternity loss within their own nests. Breeding density, male age, and male size did not modify the relationship between breeding synchrony and EPP. However, older white males had higher cuckoldry rates, perhaps reflecting declines in performance associated with senescence. Results suggest that, even within species, mating strategy may modify how breeding synchrony affects rates of EPP, with positive relationships manifest only within subsets of individuals that pursue a strategy of polygyny at the expense of paternity loss.This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-13T05:36:38.799829-05:
      DOI: 10.1111/jav.01375
       
  • Opportunity costs influence food selection and giving-up density of
           dabbling ducks
    • Authors: Heath M. Hagy; Joshua D. Stafford, Randolph V. Smith, Aaron P. Yetter, Christopher S. Hine, Michelle M. Horath, Christopher J. Whelan
      Abstract: The interaction of animals with their food can yield insights into habitat characteristics, such as perceived predation risk and relative quality. We deployed experimental foraging patches in wetlands used by migrating dabbling ducks Anas spp. in the central Illinois River Valley to estimate variation in seed removal and giving-up density (GUD; i.e. density of food remaining in patches following abandonment) with respect to seed density, seed size, seed depth in the substrate, substrate firmness, perceived predation risk, and an energetic profitability threshold (i.e. critical food density). Seed depth and the density of naturally-occurring seeds outside of experimental plots affected seed removal and GUD in experimental patches more than perceived predation risk, seed density, seed size or substrate firmness. The greatest seed removal and lowest GUDs in experimental patches occurred when food resources in alternative foraging locations outside of plots (i.e. opportunity costs) appeared to be near or below a critical food density (i.e. 119–181 kg ha–1). Giving-up densities varied substantially from a critical food density across a range of food densities in alternative foraging locations suggesting that fixed GUDs should not be used as surrogates for critical food densities in energetic carrying capacity models. Foraging and resting rates in and near experimental foraging patches did not reflect patterns of seed removal and were poor predictors of GUD and foraging habitat quality. Our results demonstrated the usefulness of GUDs as indicators of habitat quality for subsurface, benthic foragers relative to other available foraging patches and suggested that food may be limited for dabbling ducks during spring migration in some years in the midwestern USA.
      PubDate: 2017-03-08T05:36:51.365711-05:
      DOI: 10.1111/jav.01275
       
  • Effect of haemosporidian infections on host survival and recapture rate in
           the blue tit
    • Authors: Edyta Podmokła; Anna Dubiec, Szymon M. Drobniak, Joanna Sudyka, Adam Krupski, Aneta Arct, Lars Gustafsson, Mariusz Cichoń
      Abstract: Parasites are ubiquitous in the wild and by imposing fitness costs on their hosts they constitute an important selection factor. One of the most common parasites of wild birds are Plasmodium and Haemoproteus, protozoans inhabiting the blood, which cause avian malaria and malaria-like disease, respectively. Although they are expected to cause negative effects in infected individuals, in many cases studies in natural populations failed to detect such effect.Using data from seven breeding seasons (2008–2014), we applied a multistate capture–mark–recapture approach to study the effect of infection with malaria and malaria-like parasites, individual age and sex on the probability of survival and recapture rate in a small passerine, the blue tit Cyanistes caeruleus, inhabiting the island of Gotland, Sweden. We found no effect of infection on survival prospects. However, the recapture rate of infected individuals was higher than that of uninfected ones. Thus, while our data do not support the presence of infection costs in terms of host survival, it suggests that parasites from the genera Plasmodium and Haemoproteus may affect some aspects of host behaviour, which translates into biased estimation of infection frequency at the population level.
      PubDate: 2017-03-08T05:25:40.257616-05:
      DOI: 10.1111/jav.01108
       
  • Soaring across continents: decision-making of a soaring migrant under
           changing atmospheric conditions along an entire flyway
    • Authors: Wouter M. G. Vansteelant; Judy Shamoun-Baranes, James McLaren, Jan van Diermen, Willem Bouten
      Abstract: Thermal soaring birds reduce flight-energy costs by alternatingly gaining altitude in thermals and gliding across the earth's surface. To find out how soaring migrants adjust their flight behaviour to dynamic atmospheric conditions across entire migration routes, we combined optimal soaring migration theory with high-resolution GPS tracking data of migrating honey buzzards Pernis apivorus and wind data from a global numerical atmospheric model.We compared measurements of gliding air speeds to predictions based on two distinct behavioural benchmarks for thermal soaring flight. The first being a time-optimal strategy whereby birds alter their gliding air speeds as a function of climb rates to maximize cross-country air speed over a full climb– glide cycle (Vopt). The second a risk-averse energy-efficient strategy at which birds alter their gliding air speed in response to tailwinds/headwinds to maximize the distance travelled in the intended direction during each glide phase (Vbgw).Honey buzzards were gliding on average 2.05 ms– 1 slower than Vopt and 3.42 ms– 1 faster than Vbgw while they increased air speeds with climb rates and reduced air speeds in tailwinds. They adopted flexible flight strategies gliding mostly near Vbgw under poor soaring conditions and closer to Vopt in good soaring conditions.Honey buzzards most adopted a time-optimal strategy when crossing the Sahara, and at the onset of spring migration, where and when they met with the best soaring conditions. The buzzards nevertheless glided slower than Vopt during most of their journeys, probably taking time to navigate, orientate and locate suitable thermals, especially in areas with poor thermal convection.Linking novel tracking techniques with optimal migration models clarifies the way birds balance different tradeoffs during migration.
      PubDate: 2017-03-08T05:06:05.840785-05:
      DOI: 10.1111/jav.01298
       
  • How birds colonize cities: genetic evidence from a common waterbird, the
           Eurasian coot
    • Authors: Piotr Minias; Radosław Włodarczyk, Alina Minias, Jarosław Dziadek
      Abstract: Much effort has been devoted to identify ecological and life–history traits which facilitate urban colonization by wild avian species, but surprisingly little is known about the population–level mechanisms of urbanization processes. In general, two different patterns of urban colonization have been proposed: 1) the model of independent colonization predicts that birds colonize cities independently in different geographical regions; 2) the model of leapfrog colonization assumes a single colonization event, while additional urban populations are established from the initial urban populations. The aim of this paper was to determine the pattern of urban colonization in a common waterbird, the Eurasian coot Fulica atra. For this purpose, we analysed microsatellite variation in three pairs of urban and rural coot populations from central Poland. We found that a newly–established urban population was genetically more similar to neighbouring rural populations than to long–established urban populations, as indicated by the analysis of fixation index, genetic distance and Bayesian assignment of individuals to genetic clusters. These results are consistent with the model of independent colonization, where neighbouring rural populations are a source of individuals that colonize new urban areas. However, our analysis also showed significant differentiation between long–established urban populations and adjacent rural populations, suggesting that genetic connectivity between two types of habitat decreases with increasing time since urbanization. Our study shows high complexity of urbanization processes in wild animal populations, as well as it underpins utility of molecular tools in studying population–level mechanisms of urbanization.‘This article is protected by copyright. All rights reserved.’
      PubDate: 2017-03-07T09:45:38.670282-05:
      DOI: 10.1111/jav.01334
       
  • Campylobacter jejuni infection associated with relatively poor condition
           and low survival in a wild bird.
    • Authors: Conor C. Taff; Andrea K. Townsend
      Abstract: Campylobacter jejuni is the most common foodborne pathogen in industrialized countries. Most human infections come from contaminated poultry, but wild birds are also known to harbor C. jejuni. Wild birds are often described as asymptomatic carriers, but this assumption is based on domestic poultry research. We studied the effects of C. jejuni infection on body condition and survival of adult and nestling American Crows (Corvus brachyrhynchos) in Davis, California. Previous work demonstrated that more than half of the crows in this population are infected with C. jejuni and that at least some of the isolates carried by crows are similar to those found in domestic animals and humans. In this study, we compared the body condition of infected and uninfected individuals at the time of capture among adults (n = 44; 52% infected) and nestlings (n = 97; 77% infected). We subsequently monitored these banded individuals for up to 3 years and used mark-recapture survival analysis to estimate relationships between infection status and later survival. We found that adult crows infected with C. jejuni were in poor condition relative to uninfected adults: average body mass of infected birds was 12% lower, whereas average body size did not differ between the two groups. Likewise, apparent survival probability was lower for infected adults. In contrast, nestling body condition, fledging success, and survival did not differ by infection status. This is the first study to document adverse effects of C. jejuni infection in a free-living, wild bird. If these effects are widespread, C. jejuni exposure may be a cause of conservation concern for some species, especially when human activities increase exposure to infections or introduce novel strains to wild bird populations. Our results add to the growing body of work demonstrating hidden long-term costs of seemingly mild infections in wild populations.This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-07T09:45:34.837203-05:
      DOI: 10.1111/jav.01282
       
  • High fidelity: extra-pair fertilisations in eight Charadrius plover
           species are not associated with parental relatedness or social mating
           system
    • Authors: Kathryn H. Maher; Luke J. Eberhart-Phillips, András Kosztolányi, Natalie dos Remedios, María Cristina Carmona-Isunza, Medardo Cruz-López, Sama Zefania, James St Clair, Monif AlRashidi, Michael A. Weston, Martín A. Serrano-Meneses, Oliver Krüger, Joseph I. Hoffman, Tamás Székely, Terry Burke, Clemens Küpper
      Abstract: Extra-pair paternity is a common reproductive strategy in many bird species. However, it remains unclear why extra-pair paternity occurs and why it varies among species and populations. Plovers (Charadrius spp.) exhibit considerable variation in reproductive behaviour and ecology, making them excellent models to investigate the evolution of social and genetic mating systems. We investigated inter- and intra-specific patterns of extra-pair parentage and evaluated three major hypotheses explaining extra-pair paternity using a comparative approach based on the microsatellite genotypes of 2,049 individuals from 510 plover families sampled from twelve populations that constituted eight species. Extra-pair paternity rates were very low (0 to 4.1% of chicks per population). No evidence was found in support of the sexual conflict or genetic compatibility hypotheses, and there was no seasonal pattern of extra-pair paternity (EPP). The low prevalence of EPP is consistent with a number of alternative hypotheses, including the parental investment hypothesis, which suggests that high contribution to care by males restricts female plovers from engaging in extra-pair copulations. Further studies are needed to critically test the importance of this hypothesis to plover mate choice.This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-07T09:30:39.552035-05:
      DOI: 10.1111/jav.01263
       
  • An experimental approach to the Brood Reduction Hypothesis in Magellanic
           Penguins
    • Authors: Barrionuevo Melina; Esteban Frere
      Abstract: In many bird species, eggs in a brood hatch within days of each other, leading to a size asymmetry detrimental to younger siblings. Hatching asynchrony is often thought of as an adaptive strategy, and the most widely studied hypothesis in relation to this is the “Brood Reduction Hypothesis”. This hypothesis states that when food resources are unpredictable, hatching asynchrony will allow the adjustment of the brood size maximizing fledging success and benefitting parents. The Magellanic Penguin (Spheniscus magellanicus) is an appropriate species to test this hypothesis because it has a 2-egg clutch that hatches over a 2-day interval with a broad range of variation (-1 to 4 days), it shows facultative brood reduction, and food abundance between breeding seasons is variable. We performed a manipulative study at Isla Quiroga, Argentina, during three breeding seasons (2010-2012) by forcing broods to hatch synchronously (0 days) or asynchronously (2 or 4 days). Years were categorized based on estimated food abundance. Our study provided mixed results because in the low estimated food abundance year asynchronous broods did not have higher nestling survival than synchronous broods, and the second-hatchling in asynchronous broods did not die more often than those in synchronous broods. On the other hand, younger siblings of 4-day asynchronous broods starved earlier than those of synchronous broods, and 2-day asynchronous broods fledged heavier young than synchronous broods. Asynchronous hatching would seem to benefit reproduction in this species, not with respect to survival, but in terms of the advantages it can accord to nestlings and, in terms of lower costs, for parents raising nestlings.This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-07T09:30:35.025814-05:
      DOI: 10.1111/jav.01200
       
  • Evaluating the reliability of species distribution models with an indirect
           measure of bird reproductive performance
    • Authors: Olatz Aizpurua; Lisette Cantú-Salazar, Gilles San Martin, Francesc Sardà-Palomera, Gabriel Gargallo, Sergi Herrando, Lluís Brotons, Nicolas Titeux
      Abstract: Measures of fitness such as reproductive performance are considered reliable indicators of habitat quality for a species. Such measures are, however, only available in a restricted number of sites, which prevents them from being used to quantify habitat quality across landscapes or regions. Alternatively, species presence records can be used along with environmental variables to build models that predict the distribution of species across larger spatial extents. Model predictions are often used for management purposes as they are assumed to describe the quality of the habitats to support a species. Yet, given that species are often present both in optimal and suboptimal areas, the use of data collected during the breeding season to build these models may potentially result in misleading predictions of habitat quality for the reproduction of the species, with potentially significant conservation consequences. In this study we analysed the relationship between fitness parameters informing on habitat quality for reproduction and predictions of species distribution models at multiple spatial scales using two independent sets of data. For 19 passerine bird species, we compared an indirect measure of reproductive performance (ratio of juveniles-to-adults) – obtained from Constant Effort Sites (CES) mist-netting data in Catalonia – with the predictions of models based on bird presence records collected during the Catalan Breeding Bird Atlas (CBBA). A positive relationship between the predictions derived from species distribution models and the reproductive performance of the species was found for half of the species at one or more spatial scales. This result suggests that species distribution models may help to predict habitat quality for some species over some extents. However, caution is needed as this is not consistent for all species at all scales. Further work based on species- and scale-specific approaches is now required to understand in which situations species distribution models provide predictions that are in line with reproductive performance.This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-07T09:30:27.248048-05:
      DOI: 10.1111/jav.01218
       
  • The Long Shadow of Senescence: Age Impacts Survival and Territory Defense
           in Loons
    • Authors: Walter H. Piper; Kristin M. Brunk, Joel A. Flory, Michael W. Meyer
      Abstract: Senescence, increased mortality that occurs among animals of advanced age, impacts behavior and ecology in many avian species. We investigated actuarial, reproductive, and behavioral senescence using capture, marking, and resighting data from a 26-year study of common loons (Gavia immer). Territorial residents of both sexes exhibited high annual survival (0.94) until their mid 20s, at which point survival fell to 0.76 and 0.77 in males and females, respectively. Sexual symmetry in actuarial senescence is somewhat surprising in this species, because males make a substantially greater investment in territory defense and chick-rearing and because males engage in lethal contests for territory ownership. Survival of displaced breeders (0.80) was lower than that of territorial residents in both young and old individuals. Old males and females also experienced slightly higher annual probability of eviction (0.16 for males; 0.17 for females) than prime-aged breeders (0.13 for both sexes), indicating senescence in territory defense. Prime-aged males reclaimed territories at a high rate (0.49), in contrast to females of the same age (0.33). However, old males resettled with success (0.35) similar to old females (0.31), suggesting that males decline in competitive ability as they age. Nonetheless males, but not females, showed an apparent increase in breeding success over the entire lifetime, a possible indication that very old males make a terminal investment in reproductive output at the cost of survival.This article is protected by copyright. All rights reserved.
      PubDate: 2017-03-04T00:40:27.600463-05:
      DOI: 10.1111/jav.01393
       
  • Intrinsic factors drive spatial genetic variation in a highly vagile
           species, the wedge-tailed eagle (Aquila audax), in Tasmania
    • Authors: Christopher P. Kozakiewicz; Scott Carver, Jeremy J. Austin, Jill M. Shephard, Christopher P. Burridge
      Abstract: Knowledge of dispersal in a species, both its quantity and the factors influencing it, are crucial for our understanding of ecology and evolution, and for species conservation. Here we quantified and formally assessed the potential contribution of extrinsic factors on individual dispersal in the threatened Tasmanian population of wedge-tailed eagle, Aquila audax. As successful breeding by these individuals appears strongly related to habitat, we tested the effect of landscape around sampling sites on genetic diversity and spatial genetic variation, as these are influenced by patterns of dispersal. Similarly, we also tested whether habitat intervening sampling sites could explain spatial genetic variation. Twenty microsatellites were scored, but only a small proportion of spatial genetic variation (4.6%) could be explained by extrinsic factors, namely habitat suitability and elevation between sites. However, significant clinal genetic variation was evident across Tasmania, which we explain by intrinsic factors, likely high natal philopatry and occasional long-distance dispersal. This study demonstrates that spatial genetic variation can be detected in highly vagile species at spatial scales that are small relative to putative dispersal ability, although here there was no substantial relationship with landscape factors tested.This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-28T10:20:23.222025-05:
      DOI: 10.1111/jav.01326
       
  • Evaluating interspecific niche overlaps in environmental and geographic
           spaces to assess the value of umbrella species
    • Authors: Yoan Fourcade; Aurélien G. Besnard, Jean Secondi
      Abstract: The concept of umbrella species assumes that concentrating resources on the protection of a single species contributes to the conservation of a suite of species and ecological processes belonging to the same ecosystem. The environmental requirements and geographical distribution of the umbrella species should thus overlap those of the group of targeted species. In western France, the conservation of several large grassland floodplains relies on agri-environmental schemes targeting one single bird species, the corncrake Crex crex. It is considered as an umbrella species but no real assessment of its effectiveness has been carried out so far. We used a two-step methodology to assess the potential of the corncrake to act as an umbrella species by estimating niche overlap in the environmental and geographic space between the main ground-nesting species of the bird community in these grasslands, including the corncrake and four passerines. The five species showed substantial differences in their ecological niches so that their distributions did not perfectly overlap. Overlaps in predicted distributions between pairs of species depended on the threshold used to convert suitability to binary maps. Moreover, the number of species that could be protected by a candidate umbrella species was affected by the overlap criterion of success. Although the corncrake may be used as an umbrella species, it would be outperformed by several passerine species. Our study highlights the potential of using niche overlap to select umbrella species. It also reveals the importance of analysing the sensitivity of outputs when changing thresholds and overlap criteria.
      PubDate: 2017-02-21T06:31:04.1398-05:00
      DOI: 10.1111/jav.01153
       
  • On the use of heterospecific information for nest site selection in birds
    • Authors: Tore Slagsvold; Karen L. Wiebe
      PubDate: 2017-02-20T10:00:24.40835-05:0
      DOI: 10.1111/jav.01398
       
  • Variability in stable isotopes of snowy owl feathers and contribution of
           marine resources to their winter diet
    • Authors: Audrey Robillard; Gilles Gauthier, Jean-François Therrien, Guy Fitzgerald, Jennifer F. Provencher, Joël Bêty
      Abstract: The snowy owl is an elusive arctic predator known for its nomadic behaviour. Satellite tracking has revealed that some adult snowy owls could make an extensive use of the marine environment during the non-breeding season. However, the relative contribution of marine resources to their diet is unknown. Stable isotope analyses can be useful to document the diet of mobile animals during periods of the year when individuals are less accessible. This study aimed to assess variation in isotopic values (δ13C and δ15N) of various feather types, and the usefulness of feathers to determine the contribution of the marine environment to the winter diet of snowy owls captured in summer. We sampled feathers coming from 6 body regions of 18 breeding females at two sites in the eastern Canadian Arctic in 2013 and 2014. Prior to analyses, diet-tissue discrimination factors of snowy owl feathers were established in captivity. Variability in isotopic values among feather types was relatively low and pairwise correlations in isotopic values between feathers on the same individual were variable and often low, which suggests differences in the diet at the time when various feathers were synthesized. Diet reconstruction models detected a contribution of marine sources to snowy owl feathers ranging from 4% to 19% among feather types. However, the marine contribution was highly variable when single feathers were examined within individuals, ranging from 3% to 71%. This indicated that no single feather type could be used alone to reliably infer the contribution of marine resources to the winter diet of owls, possibly due to a high variability in the timing and sequence of molt. For asynchronous molters like snowy owls, we recommend sampling multiple feathers from various body regions, excluding wing feathers, to investigate winter diet or habitat use.This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-16T04:31:03.056969-05:
      DOI: 10.1111/jav.01257
       
  • The evolution of feather coloration and song in Old World orioles (genus
           Oriolus)
    • Authors: Beata Matysioková; Nicholas Friedman, Lucia Turčoková, Vladimír Remeš
      Abstract: What is the tempo and mode of evolution – how fast and in what pattern do traits evolve – is a major question of evolutionary biology. Here we studied patterns of evolutionary change in visual and acoustic signals in Old World orioles. Since producing multiple signals may be costly, we also tested whether there was an evolutionary trade-off between the elaboration of those two types of signals. We studied 30 Oriolus taxa using comparative methods and a recent molecular phylogeny. Morphology and plumage hue evolved comparatively slowly, whereas song evolved rapidly. Among individual feather patches, the evolutionary rate of color was slowest in primaries, which are critical for flapping flight, and fastest in patches exposed to observers (mantle and breast). Thus, primaries seem to be under functional constraint while the evolution of visually exposed patches is perhaps shaped by sexual selection. Song evolution was comparatively fast, but also attracted to a single optimum. This may be due to selection for signal efficacy, because all orioles inhabit similar forested habitats. Only color diversity was best fit by a speciational model: the biggest changes in coloration were concentrated at speciation events, thus perhaps linked to the evolution of species recognition. Our analysis did not reveal any evolutionary trade-off between acoustic and visual signals, suggesting that the elaboration of visual and acoustic signals in the Old World orioles evolved independently. Our study shows that patterns of evolutionary change may be surprisingly complex even within a single clade of birds and thus further studies are needed to identify general patterns of signal macroevolution.This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-14T04:40:41.571179-05:
      DOI: 10.1111/jav.01175
       
  • Cohabitation with farm animals rather than breeding effort increases the
           infection with feather-associated bacteria in the barn swallow Hirundo
           rustica
    • Authors: Attila Fülöp; Csongor I. Vágási, Péter L. Pap
      Abstract: Feather-associated bacteria are widespread inhabitants of avian plumage. However, the determinants of the between-individual variation in plumage bacterial loads are less well understood. Infection intensities can be determined by ecological factors, such as breeding habitat, and can be actively regulated by hosts via preening. Preening, yet, is a resource intensive activity, and thus might be traded-off against reproductive investment in breeding birds. Here, we studied barn swallows Hirundo rustica to assess the bacterial cost of reproduction in relation to nesting site micro-habitats. Barn swallows prefer to breed in the company of large-sized farm animals, although the presence of mammalian livestock in barns assures a warm and humid micro-climate that favours bacterial proliferation. Thus, we experimentally manipulated brood sizes of birds breeding in barns with, or without, farm animals and measured total cultivable bacteria (TCB) and feather-degrading bacteria (FDB) from the plumage. We found that the abundance of feather-associated bacteria (i.e. both TCB and FDB) in females, but not males, breeding in barns with livestock were significantly higher than in conspecifics breeding in empty barns. Plumage bacterial loads, however, were not affected by brood size manipulations in either sex. In addition, we report a negative relationship between both TCB and FDB and hatching date in females, and several sex and seasonal differences in plumage bacterial abundances. Our study is the first to show that breeding micro-habitat (i.e. livestock co-tenancy) has consequences for the abundance of feather-associated bacteria.This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-14T04:40:35.833897-05:
      DOI: 10.1111/jav.01262
       
  • Modelling avian growth with the Unified-Richards: as exemplified by
           wader-chick growth
    • Authors: Kathleen M. C. Tjørve; Even Tjørve
      Abstract: Postnatal growth in birds is traditionally modelled by fitting three-parameter models, namely the logistic, the Gompertz, or the von Bertalanffy models. The purpose of this paper is to address the utility of the Unified-Richards (U-Richards) model. We draw attention to two forms of the U-Richards and lay down a set of recommendations for the analysis of bird growth, in order to make this model and the methods more accessible. We examine the behaviour of the four parameters in each model form and the four derived measurements, and we show that all are easy to interpret, and that each parameter controls a single curve characteristic. The two parameters that control the inflection point, enable us to compare its placement in two dimensions, 1) inflection value (mass or length at inflection) and 2) inflection time (time since hatching), between data sets (e.g. between biometrics or between species). We also show how the parameter controlling growth rate directly presents us with the relative growth rate at inflection, and we demonstrate how one can compare growth rates across data sets. The three traditional models, where the inflection value is fixed (to a specific percentage of the upper asymptote), provide incompatible growth-rate coefficients. One of the two forms of the U-Richards model makes it possible to fix not only the upper asymptote (adult value), but also the intersection with the y-axis (hatching value). Fitting the new model forms to data validates the usefulness of interpreting the inflection placement in addition to the growth rate. It also illustrated the advantages and limitations of constraining the upper asymptote (adult value) and the y-axis intersection (hatching value) to fixed values. We show that the U-Richards model can successfully replace some of the commonly used growth models, and we advocate replacing these with the U-Richards when modelling bird growth.
      PubDate: 2017-02-13T08:40:44.89927-05:0
      DOI: 10.1111/jav.00992
       
  • Habitat suitability and the constraints of migration in New World warblers
    • Authors: David P. L. Toews
      Abstract: Identifying the factors that influence geographic range limits can illustrate the various ecological, physiological, and evolutionary constraints imposed on a species. The range limits of migratory birds are particularly challenging to study as they occur in disjunct regions at different times of the year, which can impose different constraints. Travel between breeding and wintering regions poses a significant energetic and navigational challenge to birds, although it is not clear how these movements influence breeding dispersal and range expansion. Here I ask whether the possible costs of migration limit the breeding ranges of wood warblers, a group of birds with an extensive history of ecological and evolutionary studies. I used occurrence records for multiple wood warbler species, breeding primarily in the boreal forest of North America, to generate environmental niche models. I tested for over-prediction of habitat suitability into the western boreal forest, where most these species do not have occurrence records but where there is presumably suitable habitat. I found that some of these vagile taxa, primarily found east of the Rocky Mountains, also have predicted habitat suitability that extends into the north and west, where they have little to no occurrence records. I discuss several possible explanations for this discordance. In particular, the patterns are consistent with the costs of a long-distance migration limiting the benefits of range expansion, as migration may become too onerous as the distance between breeding and wintering areas increases. These results speak to the process of niche filling more generally and call attention to an under-appreciated explanation for why migratory species may not fully occupy their fundamental niche.This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-10T05:50:52.183644-05:
      DOI: 10.1111/jav.01157
       
  • Population differentiation in whiskered auklets (Aethia pygmaea): do
           diurnal and nocturnal colonies differ in genetics, morphometry and
           acoustics'
    • Authors: Olesya S. Pshenichnikova; Anna V. Klenova, Pavel A. Sorokin, Nikolay B. Konyukhov, Alexander V. Andreev, Sergei P. Kharitonov, Victor A. Zubakin, Yuri B. Artukhin, Carley R. Schacter
      Abstract: Despite a great number of empirical studies, the mechanisms of population differentiation and the factors that influence this process, particularly in seabirds, remain insufficiently understood. Here we analyzed population structure in the whiskered auklet (Aethia pygmaea), a previously poorly studied alcid species with unusual differentiation in colony attendance rhythms (i.e. diurnal in the Sea of Okhotsk vs. nocturnal in the Bering Sea), and examined the influence of it on intraspecific differentiation. For this study, we analyzed morphometric measurements, acoustic variables, mitochondrial control region fragment and five microsatellite loci from nine whiskered auklet colonies spanning the breeding range. Previous research has shown a clinal variation in this species. We build on this analysis by adding auklets from more colonies, for the first time analyzing vocalizations from different colonies and genetic structure of this species. Our data supports a clinal variation in morphometric and acoustic characters with the largest size and the lowest call frequency in western birds, and the smallest size and highest call frequency in the east. We also found two mitochondrial lineages – whiskered auklets from colonies in the Sea of Okhotsk and the Commander Is. (Bering Sea) and from the Aleutian Is. (Bering Sea), that were presumably formed during Sangamonian interglacial period (115000-130000 years ago). Genetic clusters found did not reflect differences in colony attendance rhythms, suggesting that the last was shaped by other factors (e.g. differences in predator pressure) and is unlikely to have participated in the formation of population structure. Colony fidelity, mobility of birds, proximity of foraging grounds and location of colonies in relation to seasonal ice pack, seem to be more likely determinants of intraspecific differentiation.This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-08T05:10:26.506022-05:
      DOI: 10.1111/jav.01124
       
  • Climate determinants of breeding and wintering ranges of lesser kestrels
           in Italy and predicted impacts of climate change
    • Authors: Michelangelo Morganti; Damiano Preatoni, Maurizio Sarà
      Abstract: Climate warming would theoretically create conditions for the breeding range expansion of pseudo-steppe Mediterranean and long-distance migrant species and provide the possibility for these to overwinter in the same breeding areas. However, contemporary changes in rainfall regimes might have negative effects on the climate suitability and in turn, shrink species potential range. The lesser kestrel, Falco naumanni, is highly sensitive to rainfall oscillations and has recently extended its Italian breeding range towards northern latitudes and increasing its wintering records. We modelled the effects of temperature and rainfall on current and future climate suitability for lesser kestrels in both the breeding and wintering periods by using MaxEnt. Models were based on the distribution of 298 colonies and 45 wintering records. Future climate suitability was assessed under eight different scenarios.Spring rainfall amount resulted as the main determinant of breeding climate suitability, so its predicted reduction will determine a shrinkage in suitable areas (-42.10% in 2050; -32.07% in 2070). Specifically, the 66.05% of Italian colonies will be outside the climatically suitable area by 2050. However wide areas, suitable under current climate conditions, are still not occupied by lesser kestrel and allow the potential expansion of its Italian breeding range in the short term. Temperature seasonality mainly determined the species’ winter climate suitability, which is overall predicted to boost in the next decades (+145.03% in 2050; and +123.91% in 2070). All but one future scenarios predicted a northward shift of about 40 km for both breeding and wintering climate suitability. Despite its recent expansion, we have found that climate change will pose conservation concerns for the Italian breeding population of lesser kestrels. Indeed, changes in non-climate factors will also outline the future suitability of the Italian range for lesser kestrels in both seasons with effects that might both strengthen or mitigate climate effects.This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-08T05:05:37.380048-05:
      DOI: 10.1111/jav.01179
       
  • Age-related parasite load and longevity patterns in the sedge warbler
           Acrocephalus schoenobaenus
    • Authors: W Bielański; A. Biedrzycka, T. Zając, A. Ćmiel, W. Solarz
      Abstract: We report the results from a 9-year study on parasite infection in males of a small migrant passerine, the sedge warbler Acrocephalus schoenobaenus. Every year, for each male caught during territory establishment we estimated infection intensity of two lineages of Haemoproteus belopolskyi (SW1 and SW3), using molecular methods. We found a significant relationship between infection intensity and males’ longevity in both studied lineages. There was severe mortality of second-year sedge warblers after their first breeding season, with lower parasite load in survivors. The lower infection intensity in older age classes was related to between-individual change in both lineages, but was also a result of differences in infection intensity during the lifetime of individual males in the SW3. The relation between parasite load and longevity suggests that parasite load may be an age-dependent factor influencing individual survival.This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-08T05:00:32.970545-05:
      DOI: 10.1111/jav.00949
       
  • Integrating demography, dispersal and interspecific interactions into bird
           distribution models
    • Authors: Damaris Zurell
      Abstract: Species’ ranges are primarily limited by the physiological (abiotic) tolerance of the species, described by their fundamental niche. Additionally, demographic processes, dispersal, and interspecific interactions with other species are shaping species distributions, resulting in the realised niche. Understanding the complex interplay between these drivers is vital for making robust biodiversity predictions to novel environments. Correlative species distribution models have been widely used to predict biodiversity response but also remain criticised, as they are not able to properly disentangle the abiotic and biotic drivers shaping species’ niches. Recent developments have thus focussed on (i) integrating demography and dispersal into species distribution models, and on (ii) integrating interspecific interactions. Here, I review recent demographic and multi-species modelling approaches and discuss critical aspects of these models that remain underexplored in general and in respect to birds, for example, the complex life histories of birds and other animals as well as the scale dependence of interspecific interactions. I conclude by formulating modelling guidelines for integrating the abiotic and biotic processes that limit species’ ranges, which will help to disentangle the complex roles of demography, dispersal and interspecific interactions in shaping species niches. Throughout, I pinpoint complexities of avian life cycles that are critical for consideration in the models and identify data requirements for operationalizing the different modelling steps.This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-02T09:10:49.271627-05:
      DOI: 10.1111/jav.01225
       
  • Effects of flyway-wide weather conditions and breeding habitat on the
           breeding abundance of migratory boreal waterbirds
    • Authors: Diego Pavón-Jordán; Andrea Santangeli, Aleksi Lehikoinen
      Abstract: Anthropogenic habitat loss and climate change are among the major threats to biodiversity. Bioclimatic zones such as the boreal and arctic regions are undergoing rapid environmental change, which will likely trigger changes in wildlife communities. Disentangling the effects of different drivers of environmental change on species is fundamental to better understand population dynamics under changing conditions. Therefore, in this study we investigate the synergistic effect of winter and summer weather conditions and habitat type on the abundance of 17 migratory boreal waterbird species breeding in Finland using three decades (1986–2015) of count data. We found that above-average temperatures and precipitations across the western and northern range of the wintering grounds have a positive impact on breeding numbers in the following season, particularly for waterbirds breeding in eutrophic wetlands. Conversely, summer temperatures did not seem to affect waterbird abundance. Moreover, waterbird abundance was higher in eutrophic than in oligotrophic wetlands, but long term trends indicated that populations are decreasing faster in eutrophic than in oligotrophic wetlands. Our results suggest that global warming may apparently benefit waterbirds, e.g. by increased winter survival due to more favourable winter weather conditions. However, the observed population declines, particularly in eutrophic wetlands, may also indicate that the quality of breeding habitat is rapidly deteriorating through increased eutrophication in Finland which override the climatic effects. The findings of this study highlight the importance of embracing a holistic approach, from the level of a single catchment up to the whole flyway, in order to effectively address the threats that waterbirds face on their breeding as well as wintering grounds.This article is protected by copyright. All rights reserved.
      PubDate: 2017-02-02T09:05:36.588187-05:
      DOI: 10.1111/jav.01125
       
  • Balance between site fidelity and habitat preferences in colony site
           selection by herons and egrets
    • Authors: Luis Carrasco; Yukihiko Toquenaga, Miyuki Mashiko
      Abstract: Habitat selection in avian species is a hierarchical process driven by different factors acting at multiple scales. Habitat preferences and site fidelity are two main factors affecting how colonial birds choose their breeding locations. Although these two factors affect how colonial species choose their habitats, previous studies have only focused on one factor at a time to explain the distribution of species at regional scales. Here we used 28 years of colony location data of herons and egrets around Ibaraki prefecture in Japan in order to analyze the relative importance of habitat preferences and colony site fidelity for selecting breeding locations. We used Landsat satellite images together with a ground survey-based map to create land-use maps for past years and determine the habitats surrounding the herons and egrets colonies. Combining the estimated colony site fidelity with the habitat data, we used a random forest algorithm to create habitat selection models, which allowed us to analyze the changes in the importance of those factors over the years. We found high levels of colony site fidelity for each year of study, with its relative importance as a predictor for explaining colony distribution increasing drastically in the most recent five years. The increase in collective site fidelity could have been caused by recent changes in the population size of grey herons Ardea cinerea, a key species for colony establishment. We observed a balance between habitat preferences and colony site fidelity: habitat preferences were a more powerful predictor of colony distribution until 2008, when colony site fidelity levels were lower. Considering changes in the relative importance of these factors can lead to a better understanding of the habitat selection process and help to analyze bird species’ responses to environmental changes.
      PubDate: 2017-02-02T05:25:27.21033-05:0
      DOI: 10.1111/jav.01255
       
  • Phylogeny of Penduline Tits inferred from mitochondrial and microsatellite
           genotyping
    • Authors: Hossein Barani-Beiranvand; Mansour Aliabadian, Martin Irestedt, Yanhua Qu, Jamshid Darvish, T. Szekely, Rene van Dijk, Per Ericson
      Abstract: Penduline Tits (Remiz spp) are renowned for their diverse mating and parenting strategies, and are a well-studied system by behavioural ecologists. However, the phylogenetic relationships and species delimitations within this genus are poorly understood. Here, we investigate phylogenetic relationships within the genus Remiz by examining the genetic variation in the mitochondrial cytochrome-b gene of 64 individuals and in ten autosomal microsatellite markers from 44 individuals. The taxon sampling includes individuals from all currently recognized species (R. pendulinus, R. macronyx, R. coronatus, and R. consobrinus) and most subspecies in the Palearctic region. We showed that R. coronatus and R. consobrinus are genetically well differentiated and constitute independent evolutionary lineages, separated from each other and from R. pendulinus/macronyx. However, we found no evidence for significant differentiation among R. pendulinus/macronyx individuals in mtDNA haplotypes and only marginal differences between R. pendulinus and R. macronyx in microsatellite markers. Hence, based on present data our recommendation is to treat R. pendulinus and R. macronyx as conspecific and R. coronatus and R. consobrinus as separate species.This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-18T05:10:47.254738-05:
      DOI: 10.1111/jav.01163
       
  • Geographical Variation in Reproductive Investment across Avian Assemblages
           in Europe: Effects of Environmental Drivers Differ Between Altricial and
           Precocial Species
    • Authors: Lenka Kopsová-Storchová; David Storch, Lluús Brotons, David Hořák
      Abstract: Reproductive traits provide information about the ways by which available resources are allocated during breeding. We tested for environmental drivers of large scale geographical patterns in assemblage mean clutch size, number of broods and overall reproductive investment per breeding season in European birds. We combined data about geographical distribution with published information about reproductive traits, and calculated mean trait values for avian assemblages occurring in 50x50 km grid cells. In total, we employed data from 499 species and 2059 assemblages. As the time available for breeding and the amount of food limit the reproductive effort, we related the geographical variation in reproductive traits to the length of breeding season, normalized difference vegetation index (NDVI) as a surrogate of resource availability, and its seasonality. Geographical patterns in traits may differ between reproductive modes, thus we performed the analyses separately for altricial Passerines (N=203) and precocial non-passerine species (N=164) and controlled for the effect of taxonomy. Large clutches dominated in areas with high NDVI and, in precocial birds, also in areas with high annual seasonality and a long breeding season. High number of broods and high overall reproductive investment dominated in areas with a long breeding season, and high number of broods was found also in areas with low annual seasonality, but only in precocial species. High overall reproductive investment dominated in highly productive areas and also in areas with low annual seasonality in both groups. The increase in reproductive investment is caused mostly by an increase in the number of broods related to the length of season and partly by increase in clutch size related to NDVI. We found a negative correlation between clutch size and the number of broods in Passerines, which might suggest a trade-off between these traits. Processes behind trait patterns differ between altricial and precocial species.This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-18T04:35:23.47018-05:0
      DOI: 10.1111/jav.01131
       
  • “Same procedure as last year'” – Repeatedly tracked swifts show
           individual consistency in migration pattern in successive years
    • Authors: A. H. J. Wellbrock; C. Bauch, J. Rozman, K. Witte
      Abstract: Individual migration pattern during non-breeding season is still a black box in many migratory birds. However, knowledge on both individual level and population level in migration and overwintering is fundamental to understand the life cycle of these birds and the constraints affecting them. We showed in a highly aerial migrant, the common swift Apus apus, that repeatedly tracked birds breeding at one site in Germany used the same individual-specific migration routes and wintering areas in subsequent years. In contrast, different individuals from the same breeding colony showed diverse movement patterns during non-breeding season suggesting that several suitable areas for overwintering coexist. We found lower variation in timing of autumn and spring migration within than between individuals. Our findings provide first indication of individual consistency but between-individual variation in migration pattern in a small non-passerine bird revealed by geolocators. This supports that swifts have diverse but individual-specific ‘step-by-step’ migration patterns revealing high flexibility through individual strategies.This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-16T00:50:26.529418-05:
      DOI: 10.1111/jav.01251
       
  • Ultraconserved Elements Resolve the Phylogeny of Potoos (Aves:
           Nyctibiidae)
    • Authors: Noor D. White; Charles Mitter, Michael J. Braun
      Abstract: In this study, we apply a genome-scale set of molecular markers, ultraconserved elements, to fully resolve the phylogeny of a family of secretive, nocturnal birds, the potoos (Nyctibiidae). This dataset provides an opportunity to explore some challenges of phylogenetic analyses of genome-scale datasets, which we address in several ways. We generate data matrices ranging between 2,610–4,175 loci (1,477,319–3,848,295 aligned base pairs) that represent versions of the data differing in whether or not alignments were trimmed prior to concatenation, and whether 100% or 75% of all taxa were required to be represented by data for inclusion of a given locus. These matrices are analyzed with both maximum likelihood and coalescent algorithms, to check for artifacts of concatenation. Then, we subsample our data matrix by locus into randomly-selected replicates of 125–1,000 loci, and compare the topologies and statistical support of the resulting trees to look for evidence of systematic error. In analyses of complete matrices, we find strong statistical support for all ingroup nodes of the tree with no evidence for systematic error introduced by alignment trimming, missing data, or concatenation. We find further support for that topology in our subsampling analyses and statistical topology tests. The earliest branch of the tree separates Nyctibius bracteatus from the rest of the potoos, followed successively by N. grandis and N. aethereus. Two pairs of species, N. jamaicensis plus N. griseus, and N. leucopterus plus N. aethereus comprise the distal tips of the tree. Finally, we compare our strongly supported topology to those of previous studies, and use the phylogeny to examine the evolutionary history of potoos.This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-16T00:50:25.285181-05:
      DOI: 10.1111/jav.01313
       
  • House sparrows offset the physiological trade-off between immune response
           and feather growth by adjusting foraging behavior
    • Authors: Miriam Ben-Hamo; Cynthia J. Downs, Darren J. Burns, Berry Pinshow
      Abstract: Growing feathers and mounting immune responses are both energetically costly for birds. According to the life history trade-off hypothesis, it has been posited that the costs of feather growth lead to temporal isolation between molt and other expensive activities, reproduction for example. In contrast to life cycle events, the need to mount an immune response can occur at any time, including during feather growth. Thus, we hypothesized that mounting an immune response during feather growth may divert energy and resources from feather growth and impair feather renewal. To test this hypothesis, we clipped or plucked the same feathers of male house sparrows, Passer domesticus biblicus. In the clipped group (n = 16), the feathers were absent with no regrowth; in the plucked group (n = 14), feathers were absent and regrowth was initiated. We also had an intact control group of 15 sparrows. We then initiated an inflammatory immune response by subcutaneous injection over the left breast muscle of the birds with a lipopolysaccharide (LPS) and quantified behavioral and physiological responses. We predicted that sparrows with plucked feathers would incur the highest energetic costs while mounting an immune response, and would increase their foraging effort to offset this cost. We found no difference in body mass and resting metabolic rates among sparrows subjected to the different feather and immune treatments. However, we did find that while sparrows with plucked feathers increased foraging efficiency following the immune challenge by paying fewer but longer visits to the food tray, allowing them to maintain food consumption. Foraging efficiency in sparrows with clipped feathers was reduced. We also found that quality of newly grown feathers after the immune challenge was poorer in the plucked group, suggesting that mounting an immune response competes with feather growth for resources.This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-16T00:50:22.415963-05:
      DOI: 10.1111/jav.01252
       
  • The biological background of a recurrently emerging infectious disease:
           prevalence, diversity and host specificity of Avipoxvirus in wild
           Neotropical birds
    • Authors: Michaël A. J. Moens; Javier Pérez-Tris, Borja Milá, Laura Benítez
      Abstract: Understanding which factors promote disease emergence and transmission remains a major challenge of epidemiology. A problem with research on emerging diseases is that we seldom know to what extent pathogens circulate in natural populations before emergence is already occurring. Moreover, it is critical to determine which pathogen characteristics are key to predict their emergence and invasion potential. We examined the prevalence, host specificity and evolutionary relationships of Avipoxvirus causing skin lesions in birds in two megadiverse and unexplored geographical regions of South America: an elevational gradient in the South Ecuadorian Andes, and a lowland Amazon rainforest in French Guiana. Next, we analyzed the host specificity and distribution of the worldwide Avipoxvirus diversity in order to understand their invasion potential. In French Guiana Avipoxvirus prevalence was 0 % (n=889, 94 bird species). In Ecuador, prevalence was 0.3 % (n=941, 132 bird species), with cases spanning the range of elevations between 1500 and 2500 m. These were caused by two newly described strains, one of which belonged to an American clade of Avipoxvirus shared by different bird families, and another one closely related to a strain recovered from a different family of birds in Madeira. An analysis of the host specificity and geographic distribution of all Avipoxvirus strains known worldwide finds that these viruses are usually host generalists (particularly those in the fowlpox clade), and that many closely related strains are found on multiple continents. Our study at the community level suggests that distantly related Avipoxvirus strains circulate at very low prevalence in continental tropical South America. Avipoxvirus assemblages are composed of generalist strains with different ancestry and widespread distribution, a combination of characteristics which may make these typically scarce viruses perfect candidates to emerge under favorable ecological conditions.This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-16T00:15:30.151702-05:
      DOI: 10.1111/jav.01240
       
  • Influence of device accuracy and choice of algorithm for species
           distribution modelling of seabirds: A case study using black-browed
           albatrosses
    • Authors: Petra Quillfeldt; Jan O. Engler, Janet R.D. Silk, Richard A. Phillips
      Abstract: Species distribution models (SDM) based on tracking data from different devices are used increasingly to explain and predict seabird distributions. However, different tracking methods provide different data resolutions, ranging from < 10m to>100km. To better understand the implications of this variation, we modeled the potential distribution of black-browed albatrosses Thalassarche melanophris from South Georgia that were simultaneously equipped with a Platform Terminal Transmitter (PTT) (high resolution) and a Global Location Sensor (GLS) logger (coarse resolution), and measured the overlap of the respective potential distribution for a total of nine different SDM algorithms. We found slightly better model fits for the PTT than for GLS data (AUC values 0.958±0.048 vs. 0.95±0.05) across all algorithms. The overlaps of the predicted distributions were higher between device types for the same algorithm, than among algorithms for either device type. Uncertainty arising from coarse-resolution location data is therefore lower than that associated with the modeling technique. Consequently, the choice of an appropriate algorithm appears to be more important than device type when applying SDMs to seabird tracking data. Despite their low accuracy, GLS data appear to be effective for analyzing the habitat preferences and distribution patterns of pelagic species.This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-16T00:10:26.097813-05:
      DOI: 10.1111/jav.01238
       
  • Outdoor recreation causes effective habitat reduction in Capercaillie
           Tetrao urogallus: a major threat for geographically restricted populations
           
    • Authors: Joy Coppes; Judith Ehrlacher, Rudi Suchant, Veronika Braunisch
      Abstract: Outdoor recreation inflicts a wide array of impacts on individual animals, many of them reflected in the avoidance of disturbed areas. The scale and spatial extent, however, at which wildlife populations are affected, are mostly unclear. Particularly in geographically isolated populations, where restricted habitat availability may preclude a relocation to undisturbed areas, effective habitat reduction may remain underestimated or even unnoticed, when animals stay in disturbed areas and only show small-scale responses. Based on telemetry data, we investigated the spatial and seasonal effects of outdoor recreation - in relation to landscape and vegetation conditions – on western capercaillie Tetrao urogallus, considering two scales, homerange and within-homerange habitat selection. We determined the distance-thresholds up to which recreation infrastructures were avoided and estimated the extent of affected habitat for the isolated Black Forest (Southwestern Germany) study population. While outdoor recreation did not affect homerange selection, strong effects on habitat use within the homerange were detected: Distance to recreation infrastructure (hiking and cross-country skiing trails, ski pistes) was the main determinant of habitat selection in winter; in summer, mountain bike trails and hiker's restaurants were avoided up to an average distance of 145m (CI: 60-1092m). Around winter-infrastructure, relative avoidance was recorded up to 320m (CI: 36-327m), it was reduced, however, when dense understory provided visual cover. Of the entire population area, between 8- 20% (summer) and 8- 40% (winter) were affected by outdoor recreation, mainly in the high altitudes. Even without evident large-scale shifts in species distribution, local-scale avoidance of outdoor recreation can substantially contribute to effective habitat reduction. Based on our results we recommend a general reduction in recreation infrastructure density in key habitats, the establishment of undisturbed wildlife refuges with a diameter of at least 800m, as well as enhancing visual protection by maintaining a strip of dense understory along trails.This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-16T00:10:23.785218-05:
      DOI: 10.1111/jav.01239
       
  • Effects of experimental night lighting on the daily timing of winter
           foraging in common European songbirds
    • Authors: Arnaud Da Silva; David Diez-Méndez, Bart Kempenaers
      Abstract: The ecological effects of light pollution are becoming better understood, especially in birds. Recent studies have shown that several bird species can use street lighting to extend activity into the night during the breeding season. However, most of these studies are correlational and little is known about the effects of artificial night lighting on the timing of activities outside the breeding season. During winter, low temperatures and short days may limit foraging opportunities and can negatively affect survival of resident birds. However, night lighting may allow them to expand the time niche available for foraging. Here, we report on a study where we repeatedly manipulated the amount of night lighting during early winter at automated feeding stations in a natural forest. We used video-recordings at the feeders to determine the time of the first (at dawn) and last (at dusk) foraging visits for six songbird species. We predicted that all species, and in particular the naturally early-foraging species, would advance their daily onset of foraging during the mornings with night lighting, but would show minimal or no delays in their daily cessation of foraging during the lighted evenings. We found that two early-foraging species, the blue tit and the great tit, started foraging earlier during the experimentally lighted mornings. However, in great tits, this effect was weak and restricted to nights with inclement weather. The light treatment did not have any effect on the start of foraging in the willow/marsh tit, the nuthatch, the European jay, and the blackbird. Artificial night lighting did not cause later foraging at dusk in any of the six species. Overall, our results suggest that artificial light during winter has only small effects on timing of foraging. We discuss these findings and the importance of temperature and winter weather in shaping the observed foraging patterns.
      PubDate: 2017-01-16T00:05:24.145147-05:
      DOI: 10.1111/jav.01232
       
  • Traffic noise decreases nestlings’ metabolic rates in an urban
           exploiter
    • Authors: François Brischoux; Alizée Meillère, Andréaz Dupoué, Olivier Lourdais, Frédéric Angelier
      Abstract: High levels of anthropogenic noise produced in urban areas are known to negatively affect wildlife. Although most research has been focused on the disturbances of communication systems, chronic noise exposure can also lead to physiological and behavioural changes that have strong consequences for fitness. For instance, behavioural changes mediated by anthropogenic noise (e.g. quality of parental care) may alter development and could influence nestling phenotype. We tested if nestling metabolism was influence by traffic noise in an urban exploiter, the House sparrow (Passer domesticus). We experimentally exposed breeding House sparrows from a rural area to a playback of traffic noise and we examined the impacts of this experimental procedure on metabolic rates and morphology of nestlings. We did not find an effect of traffic noise on the morphology of nestlings. Surprisingly, we found that disturbed nestlings had overall lower metabolic rates and mass-adjusted metabolic rates than undisturbed birds. Our results suggest a specific effect of noise exposure per se, rather than an indirect effect of anthropogenic noise through the quality of parental care. Both the proximate mechanisms and the ultimate consequences of such metabolic changes on nestlings remain unknown and deserve future experimental studies.This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-16T00:00:24.065355-05:
      DOI: 10.1111/jav.01139
       
  • Morphological and molecular evolution and their consequences for
           
    • Authors: Hernán Vázquez-Miranda; Josie A. Griffin, Jay M. Sheppard, Jordan M. Herman, Octavio Rojas-Soto, Robert M. Zink
      Abstract: We evaluated geographic variation and subspecific taxonomy in the Le Conte's Thrasher (Toxostoma lecontei) by analyzing DNA sequences from 16 nuclear loci, one mitochondrial DNA locus, and four study skin characters, and compared these data sets with previously published data on plumage coloration and different mtDNA genes. Morphological support for the southernmost taxon, T. l. arenicola, is relatively weak: multivariate analyses of morphometrics or back coloration do not provide diagnostic support, although one color character differs statistically. However, combined DNA analyses indicate that T. l. arenicola is diagnosable and reciprocally monophyletic, diverging from T. l. lecontei at least 140,000 years ago. Little to no past introgression across a very short geographic distance despite the long period of isolation is strong evidence of independently evolving taxa. We suggest that the lack of morphological divergence in traits related to niche use has prevented the two taxa from invading each other's range. Despite relatively weak morphological differences we suggest that these two deeply divergent lineages merit species status, and we suggest Vizcaino Thrasher for the common name corresponding to T. l. arenicola. The population size of T. l. arenicola is small and the taxon is in need of preservation attention.This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-15T22:50:29.341566-05:
      DOI: 10.1111/jav.01057
       
  • Movements of four native Hawaiian birds across a naturally fragmented
           landscape
    • Authors: Jessie L. Knowlton; David J. Flaspohler, Eben H. Paxton, Tadashi Fukami, Christian P. Giardina, Daniel S. Gruner, Erin E. Wilson Rankin
      Abstract: Animals often increase their fitness by moving across space in response to temporal variation in habitat quality and resource availability, and as a result of intra and inter-specific interactions. The long-term persistence of populations and even whole species depends on the collective patterns of individual movements, yet animal movements have been poorly studied at the landscape level. We quantified movement behavior within four native species of Hawaiian forest birds in a complex lava-fragmented landscape: Hawai‛i ‘Amakihi (Chlorodrepanis virens), ‘Oma‘o (Myadestes obscurus), ‘Apapane (Himatione sanguinea), and ‘I‘iwi (Drepanis coccinea). We evaluated the relative importance of six potential intrinsic and extrinsic drivers of movement behavior and patch fidelity: 1) forest fragment size, 2) the presence or absence of invasive rats (Rattus sp.), 3) season, 4) species, 5) age, and 6) sex. The study was conducted across a landscape of 34 forest fragments varying in size from 0.07 to 12.37 ha, of which 16 had rats removed using a treatment-control design. We found the largest movements in the nectivorous ‘Apapane and ‘I‘iwi, intermediate levels in the generalist Hawai‛i ‘Amakihi, and shortest average movement for the ‘Oma‘o, a frugivore. We found evidence for larger patch sizes increasing patch fidelity only in the ‘Oma‘o, and an effect of rat-removal increasing patch fidelity of Hawai‛i ‘Amakihi only after two years of rat-removal. Greater movement during the non-breeding season was observed in all species, and season was an important factor in explaining higher patch fidelity in the breeding season for ‘Apapane and ‘I‘iwi. Sex was important in explaining patch fidelity in ‘Oma‘o only, with males showing higher patch fidelity. Our results provide new insights into how these native Hawaiian species will respond to a changing environment, including habitat fragmentation and changing distribution of threats from climate change.This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-13T04:00:51.533761-05:
      DOI: 10.1111/jav.00924
       
  • Sunrise in the city: disentangling drivers of the avian dawn chorus onset
           in urban greenspaces
    • Authors: Jeffrey G-H. Lee; Ian MacGregor-Fors, Pamela J. Yeh
      Abstract: Urban systems are known to have a number of effects on avian diversity, density, and morphological and behavioral traits. However, no study to date has simultaneously examined the wide range of urban variables in relation to the avian dawn chorus, a complex behavioral phenomenon. Previous studies investigating adjustments of the dawn chorus onset in urban settings have mainly been confined to relationships with noise and light levels. In addition to noise and light levels, in this study we included other potentially related environmental characteristics describing vegetation structure, urban infrastructure, and human activity, all of which have been shown to be drivers of bird diversity in urban areas. We conducted dawn chorus surveys at 38 Los Angeles urban greenspaces and used a classification and regression tree analysis to identify specific urban scenarios that best explained timing differences in the dawn chorus onset. Our results show that light level was the most important determinant of the dawn chorus onset time, in which, counter-intuitively, bird communities in greenspaces with higher light levels had later onsets. In addition, noise was an important factor for the chorus onset in greenspaces with higher light levels. Although our results differ from those of previous studies, these findings highlight the importance of noise and light levels in explaining dawn chorus onset variation, indicating the need for further research in untangling this complex and ecologically important phenomenon.This article is protected by copyright. All rights reserved.
      PubDate: 2017-01-13T04:00:48.596572-05:
      DOI: 10.1111/jav.01042
       
  • Broad-scale variation in sexual dichromatism in songbirds is not explained
           by sex differences in exposure to predators during incubation
    • Abstract: The evolution of sexual dichromatism provoked one of the greatest disagreements between Charles Darwin and Alfred Russel Wallace. According to Darwin the main driving force is sexual selection, whereby choosy females prefer showy males, leading to the evolution of conspicuous male plumage. On the other hand, Wallace suggested that dichromatism may arise because nest predation favors more cryptic females. To test the role of natural selection in the evolution of dichromatism we combined quantitative data on differences in parental share in nest attentiveness (representing the strength of natural selection on males vs. females) with spectrophotometric measurements of dichromatism in 412 species of songbirds from 69 families. We expected to find stronger dichromatism in open-nesting species with more divergent parental roles and in body parts exposed during incubation. Dichromatism was not related to the differences in parental share during incubation, but it was most pronounced in lekking species, migrants, and small species. Our results thus suggest that Wallace's hypothesis is not able to explain broad-scale variation in the dichromatism of songbirds, but point to a role for sexual selection, mutual mate choice, and migration strategy in shaping the extraordinary variation in dichromatism exhibited by songbirds.This article is protected by copyright. All rights reserved.
       
  • An experimental demonstration that house finches add cigarette butts in
           response to ectoparasites
    • Abstract: Urban species encounter resources that are uncommon in nature, such as materials found in city waste. Many studies have shown that these can be harmful to wildlife. In Mexico City, house finches bring cigarette butts to their nests, which reduces the amount of ectoparasites, but also induces genotoxic damage in chicks and parents. Yet, the reason for this behaviour is unknown. One possibility is that birds extract the cellulose fibres from discarded butts simply because they resemble feathers. Alternatively, disassembled cigarette butts may be brought to the nests because they repel ectoparasites. Here we tested the latter hypothesis by assessing whether house finches (C. mexicanus) increase the amount of cigarette butts in their nests in response to a raise in ectoparasite load. When present, fibres from butts are concentrated in the nest lining. By taking it away, we simultaneously removed most of the butt material and collected the bulk of the tick population infesting each nest, as these parasites cluster in the lining. We removed the bedding of nests when chicks had recently hatched, and randomly assigned each nests to one of the following treatments: 1) addition of live ticks, 2) addition of dead ticks and 3) simulation of tick addition. Females in the live ticks’ treatment added more butt fibres to their nests than parents in control treatments. Additionally, the amount of butt fibres in the original lining also predicted the amount of fibres added after the manipulation. It seems that the tendency to bring to the nest cigarette butts is at least partially a response to current, and perhaps also past, parasite load.This article is protected by copyright. All rights reserved.
       
  • Using citizen science monitoring data in species distribution models to
           inform isotopic assignment of migratory connectivity in wetland birds
    • Abstract: Stable isotopes have been used to estimate migratory connectivity in many species. Estimates are often greatly improved when coupled with species distribution models (SDMs), which temper estimates in relation to occurrence. SDMs can be constructed using from point locality data from a variety of sources including extensive monitoring data typically collected by citizen scientists. However, one potential issue with SDM is that these data oven have sampling bias. To avoid this potential bias, an approach using SDMs based on marsh bird monitoring program data collected by citizen scientists and other participants following protocols specifically designed to maximize detections of species of interest at locations representative of the species range. We then used the SDMs to refine isotopic assignments of breeding areas of autumn-migrating and wintering Sora (Porzana carolina), Virginia Rails (Rallus limicola), and Yellow Rails (Coturnicops noveboracensis) based on feathers collected from individuals caught at various locations in the United States from Minnesota south to Louisiana and South Carolina. Sora were assigned to an area that included much of the western U.S. and prairie Canada, covering parts of the Pacific, Central, and Mississippi Flyways. Yellow Rails were assigned to a broad area along Hudson and James Bay in northern Manitoba and Ontario, as well as smaller parts of Quebec, Minnesota, Wisconsin, and Michigan, including parts of the Mississippi and Atlantic Flyways. Virginia Rails were from several discrete areas, including parts of Colorado, New Mexico, the central valley of California, and southern Saskatchewan and Manitoba in the Pacific and Central Flyways. Our study demonstrates extensive data from organized citizen science monitoring programs are especially useful for improving isotopic assignments of migratory connectivity in birds, which can ultimately lead to better informed management decisions and conservation actions.This article is protected by copyright. All rights reserved.
       
  • High altitude flights by ruddy shelduck (Tadorna ferruginea) during
           Trans-Himalayan migrations
    • Abstract: Birds that migrate across high altitude mountain ranges are faced with the challenge of maintaining vigorous exercise in environments with limited oxygen. Ruddy shelducks are known to use wintering grounds south of the Tibetan Plateau at sea level and breeding grounds north of Himalayan mountain range. Therefore, it is likely these shelducks are preforming high altitude migrations. In this study we analyse satellite telemetry data collected from 15 ruddy shelduck from two populations wintering south of the Tibetan Plateau from 2007 to 2011. During north and south migrations ruddy shelduck travelled 1,481 km (range 548 – 2,671 km) and 1,238 km (range 548-2,689 km) respectively. We find mean maximum altitudes of birds in flight reached 5,590 m (range of means 4,755 – 6,800 m) and mean maximum climb rates of 0.45 m s-1 (range 0.23 - 0.74 m s-1). The ruddy shelduck is therefore an extreme high altitude migrant that has likely evolved a range of physiological adaptations in order to complete their migrations.This article is protected by copyright. All rights reserved.
       
  • Rock Wrens preferentially use song types that improve long distance signal
           transmission during natural singing bouts
    • Abstract: When animals are capable of producing variable signals they may preferentially use some signal types over others. Among songbirds, individuals are known to alter song type form and usage patterns in contest and mating situations, but studies have not examined how song choice improves signal efficacy during broadcast song. For this study we investigated rock wren (Salpinctes obsoletus) song type use rates during natural singing bouts. We tested three hypotheses for adaptive song use during broadcast song: 1) birds improve signal content by increasing the use of high quality songs, 2) birds optimize for signal propagation by preferentially using songs that transmit well, and 3) birds maintain energy by reducing the use of costly songs. The study included 19,058 songs sung by 12 individuals, each of which had a measured song repertoire of between 52 and 117 song types which were produced at highly variable rates. Results indicated that rock wrens did not preferentially sing song types with shorter durations or fewer frequency switches, as would be expected if they selected song types to minimize delivery costs. They also did not favor songs with more rapid trills or more frequency switches, as would be expected if they adjusted song use primarily to indicate quality. Focal birds did preferentially sing significantly longer songs with lower bandwidths, lower frequencies, and slower trill rates. Results suggest that natural broadcast singing patterns are shaped more by the benefits of long distance transmission than by the benefits of advertising performance ability or the costs of song production.This article is protected by copyright. All rights reserved.
       
  • The relationship between blood parasites and ornamentation depends on the
           level of analysis in the common yellowthroat
    • Abstract: The Hamilton-Zuk hypothesis predicts that ornament expression is a signal of the ability of individuals to resist parasite infection. Thus, across a population (i.e., between-individuals) more ornamented individuals should have lower levels of parasitism. Numerous studies have tested this prediction and the results are mixed. One reason for these conflicting results may be that many studies have examined this relationship at the between-individual level, which may be affected by confounding factors such as selective mortality. Using within-subject centering we examined the relationship between male ornamentation and avian blood parasites at both the between- and the within-individual level. These relationships focus on differences in genetically-based resistance to parasites and the trade-off in resource allocation between parasite resistance and ornament expression within an individual, respectively. We studied male common yellowthroats (Geothlypis trichas), which have two plumage ornaments, a yellow, carotenoid-based bib (throat and chest) and a black, melanin-based facial mask. Surprisingly, within-individuals, an increase in parasitism between years was associated with an increase in mask size and, potentially, greater concentration of carotenoids in the yellow feathers. This suggests that males may be able to tolerate an increase in parasitism and still increase ornament expression. In contrast, ornamentation was not related to parasitism at the between-individual level. Thus, our study revealed relationships between ornaments and parasitism at the within-individual level that were not present at the between-individual level. Our results highlight the importance of examining both within- and between-individual relationships as correlations between variables, such as ornaments and parasites, may depend on the level of analysis (i.e., within- or between- individuals).This article is protected by copyright. All rights reserved.
       
  • Spatial relationships and mechanisms of coexistence between dominant and
           subordinate top predators
    • Abstract: Most forest ecosystems contain a diverse community of top-level predators. How these predator species interact, and how their interactions influence their spatial distribution is still poorly understood.Here we studied interactions among top predators in a guild of diurnal forest raptors in order to test the hypothesis that predation among competing predators (intraguild predation) significantly affects the spatial distribution of predator species, causing subordinate species to nest farther away from the dominant ones.The study analyzed a guild in southwestern Europe comprising three raptor species. For 8 years we studied the spatial distribution of used nests, breeding phenology, intraguild predation, territory occupancy, and nest-builder species and subsequent nest-user species.The subordinate species (sparrowhawk, Accipiter nisus) nested farther away from the dominant species (goshawk, A. gentilis), which preyed on sparrowhawks but not on buzzards (Buteo buteo), and closer to buzzards, with which sparrowhawks do not share many common prey. This presumably reflects an effort to seek protection from goshawks. This potential positive effect of buzzards on sparrowhawks may be reciprocal, because buzzards benefit from old sparrowhawk nests, which buzzards used as a base for their nests, and from used sparrowhawk nests, from which buzzards stole prey. Buzzards occasionally occupied old goshawk nests.These results support our initial hypothesis that interspecific interactions within the raptor guild influence the spatial distribution of predator species in forest ecosystems, with intraguild predation as a key driver. We discuss several mechanisms that may promote the coexistence of subordinate and dominant predators and the spatial assembly of this raptor guild: spatial refuges, different breeding phenology, spatial avoidance, low territory occupancy between neighboring nesting territories, nest concealment and protection, and diet segregation.This article is protected by copyright. All rights reserved.
       
  • Exogenous and endogenous corticosterone in feathers
    • Abstract: In birds, the steroid hormone corticosterone (CORT) increases in response to real or perceived threats to homeostasis. A long-term record of CORT exposure is recorded in feathers when the hormone is incorporated into the keratinized tissue, and then preserved when the mature feather is cut off from the blood supply. The opportunity to retrospectively assess the exposure of an individual to stressors by measuring the amount of CORT in a feather has generated excitement amongst avian ecologists. However, this technique is relatively new and requires additional validations. In this study, we performed experiments in wild caught European starlings (Sturnus vulgaris) to test whether: 1) CORT deposition in the feather depends on time of day and 2) whether an ecologically relevant stressor (unpredictable food access) causes a change in feather CORT. We found that exogenous CORT was incorporated into feathers during the day and the night. However, there was no difference in feather CORT between birds with unpredictable access to food and those with continuous access, indicating that feather CORT might not always detect ecologically relevant stressors.This article is protected by copyright. All rights reserved.
       
  • The relationship between plumage colouration, problem-solving and learning
           performance in great tits Parus major
    • Abstract: Recent studies suggest that individuals with better problem-solving and/or learning performance have greater reproductive success, and that individuals may thus benefit from choosing mates based on these performances. However, directly assessing these performances in candidate mates could be difficult. Instead, the use of indirect cues related to problem-solving and/or learning performance, such as condition-dependent phenotypic traits, might be favored. We investigated whether problem-solving and learning performance on a novel non-foraging task correlated with sexually selected plumage colouration in a natural population of great tits Parus major. We found that males successful in solving the task had darker blue-black crowns than non-solvers, and that males solving the task more rapidly over multiple attempts (i.e. learners) exhibited blue-black crowns with higher UV chroma and shorter-wavelength hues than non-learners. In contrast, we found no link between behavioural performance on the task and the yellow breast colouration in either sex. Our findings suggest that blue-black crown colouration could serve as a signal of problem-solving and learning performance in wild great tit males. Further research remains necessary to determine whether different sexually selected traits are used to signal cognitive performance for mate choice, either directly (i.e. cognitive performance influencing individual's health and ornamentation through diet for example) or indirectly (i.e. due to a correlation with a third factor such as individual quality or condition).This article is protected by copyright. All rights reserved.
       
  • Unmanned aircraft systems to unravel spatial and temporal factors
           affecting dynamics of colony formation and nesting success in birds
    • Abstract: Collecting information of ecological and behavioural processes often requires continuous field monitoring, however, reiterative human presence necessary to obtain monitoring data can disturb both the environment and the study species. An example of this phenomenon is the monitoring of the formation and dynamics of seabird colonies; one of the reasons for colony failure is disturbances caused by the presence of researchers or conservation managers during data collection. In this study, an Unmanned Aircraft System (UAS) was used throughout the breeding period to monitor the temporal and spatial dynamics of a black-headed gull colony in the interior of a difficult-to-access island. This methodology permitted weekly visits to the colony without disturbance, which allowed for the continuous collection of spatial and temporal data on the process of colony formation. We obtained detailed information about nesting success and its relation with the distance to the nearest incubating neighbour, as well as the colony boundary along breeding season. Thus, we successfully monitored the dynamics of a bird colony and identified factors affecting individual decision making in colony formation using a UAS.This article is protected by copyright. All rights reserved.
       
  • Study on the foraging behaviour of the European Nightjar Caprimulgus
           europaeus reveals the need for a change in conservation strategy in
           Belgium.
    • Abstract: Effective nature conservation requires coherent actions based on the best available evidence concerning protected species. Recent studies have suggested that European nightjars Caprimulgus europaeus forage outside their recognized breeding habitats, yet, for Flanders (Northern Belgium) information on nightjar foraging behaviour and key foraging habitats is lacking . To assess whether the foraging ecology of nightjars in Flanders is similar to that observed in other parts of Europe, we studied the crepuscular behaviour of this species in Bosland (north-eastern Flanders) during a five-year radio telemetry study. Tracking of 48 individuals within a coniferous forest was standardized and home ranges were calculated using a kernel density estimator (fixed kernel). Habitat use was investigated by comparing kernel placement to available habitat. Average maximal foraging distance was 2603±1094m and home ranges extended up to 691ha. We identified the key foraging habitats to be extensively-cultivated grasslands and recreational areas, areas that were previously assumed unsuitable for Belgian nightjars. Our results indicate the importance of foraging sites outside the breeding territory, confirming the findings of previous studies performed elsewhere in Europe. Incorporating our findings into future conservation plans could, therefore, lead to improved efficiency of EU conservation measures, designed for the protection of this bird species in Flanders.This article is protected by copyright. All rights reserved.
       
  • Thermoregulation in free-ranging ground woodpeckers (Geocolaptes
           olivaceus): no evidence of torpor
    • Abstract: Heterothermic responses characterised by pronounced hypometabolism and reductions in body temperature (Tb) are one of the most effective ways in which small endotherms can offset the energetic cost of endothermic homeothermy. It remains unclear, therefore, why daily torpor and hibernation are restricted to only a subset of avian lineages. To further our understanding of the phylogenetic distribution of avian torpor, we investigated winter thermoregulation in the Southern African ground woodpecker (Geocolaptes olivaceus). We considered this species a good candidate for heterothermy, because it is resident year-round in mountainous regions with cold winters and reliant on small ectothermic prey. We recorded Tb patterns in free-ranging individuals and measured Tb and metabolic rates in captive individuals. Neither free-ranging nor captive woodpeckers showed any indication of daily torpor or even shallow rest-phase hypothermia. All birds maintained bimodally distributed Tb characteristic of classic endothemic homeothermy, with a mean rest-phase Tb of 37.9 ± 0.2 °C and no data below 37.0 °C. The mean circadian amplitude of Tb was 4.2 °C, equivalent to approximately twice the expected value. There was some evidence of seasonal acclimatisation in Tb, with a small decrease in rest-phase Tb with the onset of the austral winter. Captive birds showed patterns of resting metabolic rate and Tb consistent with the classic model of endothermic homeothermy. The apparent absence of torpor in G. olivaceus supports the notion that, unlike the case in mammals, many avian taxa that may a priori be expected to benefit from deep heterothermy do not use it.This article is protected by copyright. All rights reserved.
       
  • Plumage colour and the expression of stress-related genes in gull chicks
    • Abstract: In many bird populations, individuals show remarkable differences in feather colouration, which are often linked to individual differences in physiological traits, but the mechanisms maintaining this covariation are still unclear. Here, we investigate the variability of the melanic colouration in yellow-legged gull (Larus michahellis) chicks. In this species, hatchlings show high variability in the number and colour intensity of black spots in their plumage. In gulls, last-laid eggs receive less antioxidants but higher levels of androgens than first eggs. We first explored whether these remarkable differences within the clutch affect the feather melanisation during embryo development. Melanic colouration was not related to laying order, but nestling males were darker and had a larger spotted area than nestling females. In chicks hatching from first-laid eggs, the spot size and spot lightness were negatively correlated. We also explored the effect of the developmental environment, through a cross-fostering experiment, on the expression of five stress-related genes (SOD2, ALKBH3, HSPA8, NLRC5 and TRIAP1) and their link with melanic colouration. Post-hatching hierarchy did not affect the expression of any of the tested genes, but paler chicks showed reduced expression in some studied genes (SOD2, ALKBH3 and HSPA8) in comparison to darker chicks. Our results suggest that melanic chicks suffer less stress during development.This article is protected by copyright. All rights reserved.
       
  • Density-dependent increase in superpredation linked to food limitation in
           a recovering population of northern goshawks, Accipiter gentilis
    • Abstract: A better understanding of the mechanisms driving superpredation, the killing of smaller mesopredators by larger apex predators, is important because of the crucial role superpredation can play in structuring communities and because it often involves species of conservation concern. Here we document how the extent of superpredation changed over time, and assessed the impact of such temporal variation on local mesopredator populations using 40 years of dietary data collected from a recovering population of northern goshawks (Accipiter gentilis), an archetypical avian superpredator. We then assessed which mechanisms were driving variation in superpredation, e.g., was it opportunistic, a response to food becoming limited (due to declines in preferred prey) or to reduce competition. Raptors comprised 8% of goshawk diet on average in years when goshawk abundance was high, which is higher than reported elsewhere. Additionally, there was a per capita increase in superpredation as goshawks recovered, with the proportion of goshawk diet comprising raptors increasing from 2% to 8% as the number of goshawk home-ranges increased from ≤14 to ≥25. This increase in superpredation coincided with a population decline in the most commonly killed mesopredator, the Eurasian kestrel (Falco tinnunculus), which may represent the reversal of the “mesopredator release” process (i.e., mesopredator suppression) which occurred after goshawks and other large raptors declined or were extirpated. Food limitation was the most likely driver of superpredation in this system given: 1) the substantial decline of two main prey groups in goshawk diet, the increase in diet diversity and decrease in goshawk reproductive success are all consistent with the goshawk population becoming food-limited; 2) it's unlikely to be purely opportunistic as the increase in superpredation did not reflect changes in the availability of mesopredator species; and 3) the majority of mesopredators killed by goshawks do not compete with goshawks for food or nest sites.This article is protected by copyright. All rights reserved.
       
  • Elevational replacement of two Himalayan titmice: interspecific
           competition or habitat preference'
    • Abstract: Elevational species replacement is a widely documented pattern in montane species. Although interspecific competition has been shown to be important in setting species elevational limits in tropical habitats, its effect in species of temperate regions is poorly studied. We tested the role of interspecific competition for space in the breeding season and for food in the non-breeding season in mediating the distribution of two resident titmice species in the Himalayas. We show that high elevation green-backed tits (Parus monticolus) are behaviourally dominant over low elevation cinereous tits (Parus cinereus) in both song playback and feeder trials. Despite being subordinate, at their elevational upper limit, cinereous tits occur in sympatry in human modified habitats. Our study suggests that the loss of natural habitats in the sympatric zone, not interspecific competition, might be limiting the distribution of the high-elevation green-backed tits and facilitating an upward range shift through human association in cinereous tits.
       
  • Diurnal body temperature patterns in free-ranging populations of two
           southern African arid-zone nightjars
    • Abstract: Endotherms allocate large amounts of energy and water to the regulation of a precise body temperature (Tb), but can potentially reduce thermoregulatory costs by allowing Tb to deviate from normothermic levels. Many data on heterothermy at low air temperatures (Ta) exist for caprimulgids, whereas data on thermoregulation at high Ta are largely absent, despite members of this taxon frequently roosting and nesting in sites exposed to high operative temperatures. We investigated thermoregulation in free-ranging Rufous-cheeked Nightjars (Caprimulgus rufigena) and Freckled Nightjars (Caprimulgus tristigma) in the southern African arid zone. Individuals of both species showed labile Tb fluctuating around a single modal Tb (Tb-mod). Average Tb-mod was 39.7 °C for Rufous-cheeked Nightjars and 39.0 °C for Freckled Nightjars. In both species, diurnal Tb increased with increasing Ta. At Ta ≥ 38 °C, Rufous-cheeked Nightjar mean Tb increased to 42 °C, equivalent to 2.3 °C above Tb-mod. Under similar conditions, Freckled Nightjar Tb was on average only 1.1 °C above Tb-mod, with a mean Tb of 40.0 °C. Freckled Nightjars are one of the most heterothermic caprimulgids investigated to date, but our data suggest that during hot conditions this species maintains Tb within a narrow range above Tb-mod, possibly reflecting an evolutionary tradeoff between decreased thermal sensitivity to lower Tb but increased sensitivity to high Tb. These findings reveal how general thermoregulatory patterns at similar Ta can vary even among closely related species.This article is protected by copyright. All rights reserved.
       
 
 
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