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  Subjects -> BIOLOGY (Total: 2912 journals)
    - BIOCHEMISTRY (217 journals)
    - BIOENGINEERING (100 journals)
    - BIOLOGY (1408 journals)
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BIOLOGY (1408 journals)            First | 3 4 5 6 7 8 9 10 | Last

Information Technology and Management     Hybrid Journal   (Followers: 11)
Inland Water Biology     Hybrid Journal   (Followers: 3)
Innovare Journal of Life Science     Open Access  
Insect Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 4)
Insect Conservation and Diversity     Hybrid Journal   (Followers: 3)
Insect Molecular Biology     Hybrid Journal   (Followers: 7)
Insect Science     Hybrid Journal   (Followers: 7)
Insect Systematics & Evolution     Hybrid Journal   (Followers: 3)
Insectes Sociaux     Hybrid Journal   (Followers: 3)
Insects     Open Access  
Integrative and Comparative Biology     Hybrid Journal   (Followers: 8)
Integrative Biology     Full-text available via subscription   (Followers: 5)
Interaction Studies     Hybrid Journal   (Followers: 8)
Interciencia     Open Access  
Interface Focus     Full-text available via subscription  
International Agrophysics     Open Access   (Followers: 1)
International Aquatic Research     Open Access   (Followers: 4)
International Biodeterioration & Biodegradation     Hybrid Journal   (Followers: 2)
International Journal for Computational Biology     Open Access  
International Journal for Parasitology     Hybrid Journal   (Followers: 11)
International Journal for Parasitology : Drugs and Drug Resistance     Open Access   (Followers: 4)
International Journal of Acarology     Hybrid Journal   (Followers: 1)
International journal of Advanced Biological and Biomedical Research     Open Access  
International Journal of Applied Sciences and Biotechnology     Open Access   (Followers: 2)
International Journal of Aquatic Biology     Open Access   (Followers: 12)
International Journal of Basic, Applied and Innovative Research     Open Access  
International Journal of Bio-Inspired Computation     Hybrid Journal   (Followers: 1)
International Journal of Bioassays     Open Access   (Followers: 5)
International Journal of Biochemistry & Cell Biology     Hybrid Journal   (Followers: 4)
International Journal of Biodiversity     Open Access   (Followers: 2)
International Journal of Biological and Chemical Sciences     Open Access   (Followers: 7)
International Journal of Biological Macromolecules     Hybrid Journal  
International Journal of Biological Sciences     Open Access   (Followers: 7)
International Journal of Biology     Open Access   (Followers: 4)
International Journal of Biomaterials     Open Access   (Followers: 5)
International Journal of Biomathematics     Hybrid Journal  
International Journal of Biomedical Engineering and Technology     Hybrid Journal   (Followers: 6)
International Journal of Biomedical Nanoscience and Nanotechnology     Hybrid Journal   (Followers: 5)
International Journal of Biometrics     Hybrid Journal   (Followers: 4)
International Journal of Biostatistics     Hybrid Journal   (Followers: 1)
International Journal of Brain Science     Open Access   (Followers: 1)
International Journal of Cell Biology     Open Access   (Followers: 5)
International Journal of Chemical and Life Sciences     Open Access   (Followers: 4)
International Journal of Computational Biology and Drug Design     Hybrid Journal   (Followers: 1)
International Journal of Design Engineering     Hybrid Journal   (Followers: 14)
International Journal of Ecological Economics and Statistics     Full-text available via subscription  
International Journal of Ecology & Development     Full-text available via subscription   (Followers: 2)
International Journal of Ecosystem     Open Access   (Followers: 1)
International Journal of Engineering Science     Hybrid Journal   (Followers: 6)
International Journal of Enteric Pathogens     Open Access  
International Journal of Evolution     Partially Free   (Followers: 2)
International Journal of Evolutionary Biology     Open Access   (Followers: 11)
International Journal of Experimental and Computational Biomechanics     Hybrid Journal   (Followers: 4)
International Journal of Genomics     Open Access   (Followers: 2)
International Journal of Health, Animal Science and Food Safety     Open Access   (Followers: 1)
International Journal of High Throughput Screening     Open Access   (Followers: 2)
International Journal of Impact Engineering     Hybrid Journal   (Followers: 9)
International Journal of Innovation and Applied Studies     Open Access   (Followers: 5)
International Journal of Insect Science     Open Access   (Followers: 5)
International Journal of Knowledge Discovery in Bioinformatics     Full-text available via subscription   (Followers: 2)
International Journal of Life Sciences     Open Access   (Followers: 1)
International Journal of Medical Informatics     Hybrid Journal   (Followers: 13)
International Journal of Medical Reviews     Open Access  
International Journal of Myriapodology     Open Access  
International Journal of Nanoparticles     Hybrid Journal   (Followers: 4)
International Journal of Natural Sciences     Open Access   (Followers: 1)
International Journal of Peptide Research and Therapeutics     Partially Free   (Followers: 7)
International Journal of Peptides     Open Access   (Followers: 4)
International Journal of Pharmaceutical and Life Sciences     Open Access   (Followers: 6)
International Journal of Phytoremediation     Hybrid Journal   (Followers: 2)
International Journal of Plant Genomics     Open Access   (Followers: 3)
International Journal of Plant Research     Open Access   (Followers: 4)
International Journal of Primatology     Hybrid Journal   (Followers: 5)
International Journal of Proteomics     Open Access  
International Journal of Scientific Reports     Open Access  
International Journal of Secondary Metabolite     Open Access   (Followers: 2)
International Journal of Signs and Semiotic Systems     Full-text available via subscription  
International Journal of Speleology     Open Access   (Followers: 8)
International Journal of Systems Biology and Biomedical Technologies     Full-text available via subscription   (Followers: 3)
International Journal of Tropical Insect Science     Hybrid Journal   (Followers: 1)
International Journal of Tryptophan Research     Open Access  
International Letters of Natural Sciences     Open Access  
International Review of Cell and Molecular Biology     Full-text available via subscription   (Followers: 6)
International Review of Hydrobiology     Hybrid Journal   (Followers: 2)
Intervirology     Full-text available via subscription  
IntraVital     Full-text available via subscription  
Invertebrate Biology     Hybrid Journal   (Followers: 7)
Invertebrate Neuroscience     Hybrid Journal   (Followers: 2)
Invertebrate Systematics     Hybrid Journal   (Followers: 5)
IRBM     Full-text available via subscription  
IRBM News     Full-text available via subscription  
Islets     Full-text available via subscription  
Israel Journal of Ecology and Evolution     Full-text available via subscription   (Followers: 1)
Istituto Lombardo - Accademia di Scienze e Lettere - Incontri di Studio     Open Access  
ITBM-RBM News     Full-text available via subscription   (Followers: 1)
IUBMB Life     Hybrid Journal   (Followers: 1)
IUFS Journal of Biology     Open Access  
Izvestiya Atmospheric and Oceanic Physics     Hybrid Journal   (Followers: 2)
Izvestiya, Physics of the Solid Earth     Hybrid Journal   (Followers: 2)
Japanese Journal of Applied Physics     Full-text available via subscription   (Followers: 3)

  First | 3 4 5 6 7 8 9 10 | Last

Journal Cover Journal of Avian Biology
  [SJR: 1.201]   [H-I: 52]   [22 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  [1598 journals]
  • Effects of avian malaria on male behaviour and female visitation in
           lekking Blue‐crowned Manakins
    • Abstract: Avian malaria, the infection by blood parasites of the genus Plasmodium, can reduce host fitness not only through mortality, but also by impairing the expression of sexual selection traits. Although different studies highlight the association of parasitism with a decrease in host reproductive success, few studies have addressed the role of parasites in honest signalling by lekking species. Hence, it is still uncertain which fitness components are affected by parasites in these species. We investigated whether avian malaria is associated with a decrease in mating behaviour of male Blue‐crowned Manakins, Lepidothrix coronata, and whether it affects female visitation in leks of a population in the Central Amazon. Through behavioural observations, we estimated the rates of total male activity and social interaction, as well as the frequency of female visits at individual perches. We then examined if individuals were infected with Plasmodium spp. using molecular techniques. Avian malaria was associated with a decrease in male mating behaviour in each lek, and mating behaviour correlated with female visitation. Although rates of social interaction were not correlated with avian malaria among males, we observed that interacting with several individuals within a lek may be advantageous for males, as they also vocalized and displayed more, thus increasing their chances of being visited by females. Although female visitation was not associated with avian malaria in individuals or leks, it is still possible that female visitation is indirectly affected by avian malaria through the latter's effects on male activity. We suggest a role for male activity as an honest sexual signal for females. Thus, male display rate could be used by females as cue for the probability of a male being infected. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-01T05:51:46.857053-05:
      DOI: 10.1111/jav.00864
       
  • Experimental exposure to trace metals affects plumage bacterial community
           in the feral pigeon
    • Authors: M. Chatelain; A. Frantz, J. Gasparini, S. Leclaire
      Abstract: Bacteria are fundamental associates of animals, and recent studies have highlighted their major role in host behaviour, immunity or reproductive investment. Thus, any environmental factor modifying bacterial community may affect host fitness. In birds, trace metals emitted by anthropogenic activities accumulate onto the plumage where they may alter bacterial community and ultimately affect bird fitness. Although trace metals are current major environmental issues in urban habitats, their effects on feather bacterial community have never been investigated. Here, we supplemented feral pigeons (Columba livia), an emblematic urban species, with zinc and/or lead in drinking and bath water. As expected, lead and zinc supplementations modified plumage bacterial community composition. Zinc decreased bacterial load, while lead decreased bacterial richness and the frequency of preening behaviour in birds, known to regulate feather bacteria. Our results demonstrate for the first time the effects of common urban trace metals on plumage bacterial community and shed light on one of the mechanisms by which trace metals can affect bird fitness. Further studies are now needed to investigate how this effect modulates avian life history traits known to depend on plumage bacterial community. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-01T05:51:25.747332-05:
      DOI: 10.1111/jav.00857
       
  • An experimental evaluation of the effects of geolocator design and
           attachment method on between‐year survival on Whinchats Saxicola
           rubetra
    • Authors: Emma Blackburn; Malcolm Burgess, Benedictus Freeman, Alice Risely, Arin Izang, Sam Ivande, Chris Hewson, Will Cresswell
      Abstract: Data from location logging tags have revolutionised our understanding of migration ecology, but methods of tagging that do not compromise survival need to be identified. We compared resighting rates for 156 geolocator‐tagged and 316 colour ringed‐only Whinchats on their African wintering grounds after migration to and from Eastern Europe in two separate years. We experimentally varied both light stalk length (0, 5 and 10 mm) and harness material (elastic or non‐elastic nylon braid tied on, leg‐loop ‘Rappole’ harnesses) in the second year using a reasonably balanced design (all tags in the first year used an elastic harness and 10 mm light stalk). Tags weighed 0.63 g (0.01SE), representing 4.1 % of average body mass. There was no overall significant reduction in between‐year resighting rate (our proxy for survival) comparing tagged and untagged birds in either year. When comparing within tagged birds, however, using a tied harness significantly reduced resighting rate by 53 % on average compared to using an elastic harness (in all models), but stalk length effects were not statistically significant in any model considered. There was no strong evidence that the fit (relative tightness) or added tag mass affected survival, although tied tags were fitted more tightly later in the study, and birds fitted with tied tags later may have had lower survival. Overall, on a precautionary principle, deploying tags with non‐elastic tied harnesses should be avoided because the necessary fit, so as not to reduce survival, is time‐consuming to achieve and does not necessarily improve with experience. Geolocator tags of the recommended percentage of body mass fitted with elastic leg‐loop harnesses and with short light stalks can be used without survival effects in small long‐distance migrant birds. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-01T03:22:24.986858-05:
      DOI: 10.1111/jav.00871
       
  • Individual repeatability in laying behaviour does not support the
           migratory carry‐over effect hypothesis of egg‐size dimorphism
           in Eudyptes penguins
    • Authors: Kyle W. Morrison
      Abstract: Penguins of the genus Eudyptes are unique among birds in that their first‐laid A‐egg is 54–85% the mass of their second‐laid B‐egg. Although the degree of intra‐clutch egg‐size dimorphism varies greatly among the seven species of the genus, obligate brood reduction is typical of each, with most fledged chicks resulting from the larger B‐egg. Many authors have speculated upon why Eudyptes penguins have evolved and maintained a highly dimorphic 2‐egg clutch, and why it is the first‐laid egg that is so much smaller than the second, but only recently has a testable, proximate mechanism been proposed. In most species of Eudyptes penguins females appear to initiate egg‐formation at sea during return migration to breeding colonies. In macaroni penguins E. chrysolophus, females with a shorter pre‐laying interval ashore (and thus presumably greater overlap between migration and egg‐formation) lay more dimorphic eggs, suggesting a physiological conflict may constrain growth of the earlier‐initiated A‐egg. This migratory carry‐over effect hypothesis (MCEH) was tested in eastern rockhopper penguins E. chrysocome filholi on Campbell Island, New Zealand, by recording the arrival and lay dates, body sizes, and egg masses of transponder‐tagged females over two years. Females with longer pre‐laying intervals laid less dimorphic clutches, as predicted by the MCEH. However, repeated measures of individual females revealed that within‐individual variation in egg‐size dimorphism between years was unrelated to within‐individual variation in pre‐laying interval. Egg masses, and to a lesser extent egg‐size dimorphism, were highly repeatable traits related to body size and body mass. These results and a detailed consideration of the MCEH suggest that egg‐size dimorphism in Eudyptes penguins is unlikely to be caused by a migratory carry‐over effect. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-01T03:20:50.309271-05:
      DOI: 10.1111/jav.00740
       
  • The trade‐off between clutch size and egg mass in tree swallows
           (Tachycineta bicolor) is modulated by female body mass
    • Abstract: Egg production is a costly component of reproduction for female birds in terms of energy expenditure and maternal investment. Because resources are typically limited, clutch size and egg mass are expected to be constrained, and this putative trade‐off between offspring number and size is at the core of life history theory. Nevertheless, empirical evidence for this trade‐off is equivocal at best, as individual heterogeneity in resource acquisition and allocation may hamper the detection of the negative correlation between egg number and mass within populations. Here, we investigated how female body mass and landscape composition influences clutch size, egg mass, and the relationship between these two traits. To do so, we fitted linear mixed models using data from tree swallows (Tachycineta bicolor) breeding in a network of 400 nestboxes located along a gradient of agricultural intensity between 2004 and 2011. Our dataset comprised 1463 broods for clutch sizes analyses and 4371 eggs (from 847 broods laid between 2005‐2008) for egg mass analyses. Our results showed that agricultural intensity negatively impacted clutch size, but not egg mass nor the relationship between these two traits. Female mass, on the other hand, modulated the trade‐off between clutch size and egg mass. For heavier females, both traits increased jointly, without evidence of a trade‐off. However, for lighter females, there was a clear negative relationship between clutch size and egg mass. This work shows that accounting for individual heterogeneity in body mass allows the detection of a clutch size/egg mass trade‐off that would have remained undetected otherwise. Identifying habitat and individual effects on resource allocation towards reproductive traits may help bridging the gap between predictions from theory and empirical evidence on life history trade‐offs. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-01T03:13:23.782462-05:
      DOI: 10.1111/jav.00725
       
  • Estimating the abundance of burrow‐nesting species through the
           statistical analysis of combined playback and visual surveys
    • Abstract: 1. The conservation of elusive species relies on our ability to obtain unbiased estimates of their abundance trends. Many species live or breed in cavities, making it easy to define the search units (the cavity) yet hard to ascertain their occupancy. One such example is that of certain colonial seabirds like petrels and shearwaters, which occupy burrows to breed. In order to increase the chances of detection for these types of species, their sampling can be done using two independent methods to check for cavity occupancy: visual inspection, and acoustic response to a playback call. 2. This double‐detection process allows us to estimate the probability of burrow occupancy by accounting for the probability of detection associated with each method. Here we provide a statistical framework to estimate the occupancy and population size of burrow‐dwelling species. We show how to implement the method using both Maximum Likelihood and Bayesian approaches, and test its precision and bias using simulated datasets. We subsequently illustrate how to extend the method to situations where two different species may occupy the burrows, and apply it to a dataset on Wedge‐tailed shearwaters Puffinus pacificus and Tropical shearwaters P. bailloni on Aride Island, Seychelles. 3. The simulations showed that the single‐species model performed well in terms of error and bias except when detection probabilities and occupancies were very low. The two‐species model applied to shearwaters showed that detection probabilities were highly heterogeneous. The population sizes of Wedge‐tailed and Tropical shearwaters were estimated at 13,716 (95% CI: 12,909 ‐ 15,874) and 25,550 (23,667 ‐ 28,777) pairs respectively. 4. The advantages of formulating the call‐playback sampling method statistically is that it provides a framework to calculate uncertainty in the estimates and model assumptions. This method is applicable to a variety of cavity‐dwelling species where two methods can be used to detect cavity occupancy. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-01T02:44:54.365892-05:
      DOI: 10.1111/jav.00909
       
  • Plasticity in moult speed and timing in an arctic‐nesting goose
           species
    • Abstract: Environmental constraints are strong in migratory species that breed in the Arctic. In addition to breeding, Anatidae have to renew all their flight feathers during the short arctic summer. We examine how temporal constraints and climate affect the phenology of flight feather moult in the greater snow goose (Chen caerulescens atlantica), a High Arctic nesting species. We used a database of 1412 moulting adult females measured over 15 years on Bylot Island, Nunavut. Ninth (9th) primary length was used to determine the moult stage and speed of feather growth. We found a positive relationship between median annual hatching and moult initiation dates and the slope did not differ from 1. The interval between hatching and moult initiation was thus rather fixed and geese did not initiate moult earlier when reproductive phenology was delayed. Nonetheless, there was no relationship between median hatching date and the date at which birds regained flight capacity, suggesting that date of end of moult is independent of the reproductive phenology. There was a trend for an increase in the speed of flight feather growth in years with delayed hatching date. This is the most likely mechanism that could explain moult phenology adjustment in this species. Finally, we found a positive relationship between 9th primary length (corrected for inter‐annual variations) and body condition, suggesting a delay in moulting for individuals in poor condition. These results suggest that moult plasticity is primarily governed by variations in feather growth speed. This phenotypic plasticity could be necessary to complete flight feather renewal before the end of the arctic summer, independently of reproductive phenology and spring environmental conditions. Our novel results suggest possible phenological adjustments through moult speed, which was considered constant in geese until now. This article is protected by copyright. All rights reserved.
      PubDate: 2016-02-01T02:39:01.565117-05:
      DOI: 10.1111/jav.00982
       
  • Inter‐annual variability and long‐term trends in breeding
           success in a declining population of migratory swans
    • Authors: Kevin A. Wood; Julia L. Newth, Geoff M. Hilton, Bart A. Nolet, Eileen C. Rees
      Abstract: Population declines among migratory Arctic‐breeding birds are a growing concern for conservationists. To inform the conservation of these declining populations, we need to understand how demographic rates such as breeding success are influenced by combinations of extrinsic and intrinsic factors. In this study we examined inter‐annual variation and long‐term trends in two aspects of the breeding success of a migratory herbivore, the Bewick's Swan (Cygnus columbianus bewickii), which is currently undergoing a population decline: (i) the percentage of young within the wintering population and (ii) mean brood size. We used an information‐theoretic approach to test how these two measures of productivity were influenced over a 26 year period by 12 potential explanatory variables, encompassing both environmental (e.g. temperature) and intrinsic (e.g. pair‐bond duration) factors. Swan productivity exhibited sensitivity to both types of explanatory variable. Fewer young were observed on the wintering grounds in years in which the breeding period (May to September) was colder and predator (Arctic Fox) abundance was higher. The percentage of young within the wintering population also showed negative density‐dependence. Inter‐annual variance in mean swan brood size was best explained by a model comprised of the negative degree days during the swan breeding period, mean pair‐bond duration of all paired swans (i.e. mean pair duration), and an interaction between these two variables. In particular, mean pair duration had a strong positive effect on mean brood size. However, we found no long‐term directional trend in either measure of breeding success, despite the recent decline in the NW European population. Our results highlight that inter‐annual variability in breeding success is sensitive to the combined effects of both intrinsic and extrinsic factors. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-21T02:26:59.05457-05:0
      DOI: 10.1111/jav.00819
       
  • Maternal transfer of androgens in eggs is affected by food supplementation
           but not by predation risk
    • Abstract: Mothers may affect the future success of their offspring by varying allocation to eggs and embryos. Allocation may be adaptive based on the environmental conditions perceived during early breeding. We investigated the effects of food supplementation and predation risk on yolk hormone transfer in the pied flycatcher (Ficedula hypoleuca). In a food supplementation experiment, females were food‐supplemented prior to and during egg‐laying and androgen concentrations were measured throughout the laying order. Predation risk was investigated in three different studies combining both correlative data, where flycatchers bred in close proximity to two different predator species that prey upon adult flycatchers (either Tengmalm's owl, Aegolius funereus or pygmy owl, Glaucidium passerinum), and an experimental manipulation, where flycatchers were exposed to cues of a nest predator (least weasels, Mustela nivalis). Females receiving food supplementation laid eggs with lower concentrations of androstenedione (A4) than females not receiving food supplements. Yolk testosterone (T) concentration showed the same pattern but the difference was not statically significant. Testosterone (but not A4) concentration increased within clutches, from the first to the last egg, independently of the food supplementation. Females breeding under high predation risk did not differ from control females in their yolk androgen levels (A4, T or progesterone). However, concentrations of A4 tended to be lower in the proximity of pygmy owls, which could indirectly increase offspring survival after fledging. Food supplementation during egg‐laying seems to have a stronger impact on maternal transfer of androgens than predation risk. Food availability and predation risk could differentially affect the trade‐offs of androgen allocation for the offspring when raised in good vs. dangerous environments. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-21T02:26:43.252329-05:
      DOI: 10.1111/jav.00874
       
  • Cost of reproduction: a comparison of survival rates of breeding and
           non‐breeding male ortolan buntings
    • Authors: Svein Dale
      Abstract: The cost of reproduction is expected to influence survival or future reproduction. Most previous studies have assessed cost of reproduction in relation to natural and experimental variation in number of offspring produced. The ortolan bunting (Emberiza hortulana) is a passerine bird species with biparental care, and the Norwegian population of the species has an extraordinarily skewed sex ratio with only about half of the males attracting a female, and therefore provides a rare opportunity to compare survival of males that have paired and bred with that of non‐breeders (unpaired males), which have not paid a cost of reproduction. Results showed that survival rates of paired (65.0%) and unpaired (64.2%) males did not differ. However, when comparisons were restricted to paired males that definitely had nestlings, their survival rate (76.8%) was significantly higher than that of unpaired males, and the same was the case when comparisons were further restricted to paired males that had offspring recruiting to the population the next year (76.8% survived). Males breeding successfully are likely to be a biased subset of high quality males. In analyses of a subset of males that had bred successfully when young, there was no difference in survival of paired and unpaired individuals when these males were older. In conclusion, breeding male ortolan buntings did not appear to pay a cost of reproduction in terms of reduced survival to the next year compared to non‐breeding males. These results may be explained by non‐breeding males also incurring extra costs during the breeding season, and that costs of reproduction are not shared equally among sexes in the ortolan bunting and other bird species with biparental care. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-21T02:26:10.331859-05:
      DOI: 10.1111/jav.00898
       
  • Differences in shifts of wintering and breeding ranges lead to changing
           migration distances in European birds
    • Abstract: Studies on the impact of climate change on the distributions of bird species in Europe have largely focused on one season at time, especially concerning summer breeding ranges. We investigated whether migratory bird species show consistent range shifts over the past 55 years in both breeding and wintering areas or if these shifts are independent. We then analyzed whether patterns in changing migration distances of Finnish breeding birds could be explained by habitat use, phylogeny or body size. We used long‐term datasets from the Finnish ringing centre to analyze the mean wintering latitudes of 29 species of Finnish breeding birds, then used breeding distribution data to make predictions as to whether certain species were migrating shorter or longer distances based on the comparative shifts in the wintering and breeding grounds. Our data reveal species‐specific differences in changing migration distances. We show that for many species, long‐term shifts in wintering ranges have not followed the same patterns as those in the breeding range, leading to differences in migration distances over time. We conclude that species are not adjusting predictably to climate change in their wintering grounds, leading to changing migration distances in some, but not all, species breeding in Finland. This research fills an important gap in the current climate change biology literature, focusing on individuals' entire life histories and revealing new complexities in range shift patterns. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-21T02:25:54.622704-05:
      DOI: 10.1111/jav.00941
       
  • Intermediate habitat associations by hybrids may facilitate genetic
           introgression in a songbird
    • Authors: Eric M. Wood; Sara E. Barker Swarthout, Wesley M. Hochachka, Jeffery L. Larkin, Ronald W. Rohrbaugh, Kenneth V. Rosenberg, Amanda D. Rodewald
      Abstract: Hybridization or the interbreeding of genetically discrete populations or species can occur where ranges of genetically distinct units overlap. Golden‐winged Warblers (Vermivora chrysoptera), a species that has been in steady decline for decades, highlight the potential population‐level consequences of hybridization. A major factor implicated in their decline is hybridization with their sister species, the Blue‐winged Warbler (Vermivora cyanoptera), which has likely been exacerbated by historic and current land‐use practices. We examined habitat associations of Golden‐winged and Blue‐winged Warblers, phenotypic hybrids, and cryptic hybrids (i.e., mismatch between plumage phenotype and genotype as identified by mitochondrial DNA) in an area of relatively recent range overlap and hybridization in northern New York, USA. To explore the robustness of these results, we then compared the patterns from New York with habitat associations from the central Pennsylvanian Appalachian Mountains where Blue‐winged Warblers either do not occur or are in very low abundance, yet cryptic Golden‐winged Warbler hybrids are present. From 2008 to 2011, we captured 122 birds in New York and 28 in Pennsylvania and collected blood samples, which we used to determine maternal ancestry. For each bird captured, we measured territory‐level (50‐m radius circles) habitat, and later used remote‐sensing data to quantify habitat on the territories and in surrounding areas (100‐, 250‐, and 500‐m radius circles). In New York, Golden‐winged Warblers occupied structurally heterogeneous territories surrounded by homogeneously structured, contiguous deciduous forest, far from urban areas. Blue‐winged Warblers showed opposite associations, and hybrids' habitat associations were typically intermediate. In Pennsylvania, the habitat associations of Golden‐winged Warblers and their cryptic hybrids were remarkably similar to those in New York. These findings suggest that patterns of habitat occupancy by hybrids may promote contact with Golden‐winged Warblers and thus likely facilitate genetic introgression, even in areas where the parental species are not sympatric. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-18T04:29:08.411435-05:
      DOI: 10.1111/jav.00771
       
  • Helper effects in the azure‐winged magpie Cyanopica cyana in
           relation to highly‐clumped nesting pattern and high frequency of
           conspecific nest‐raiding
    • Abstract: In avian cooperative breeding systems, many benefits obtained by social pairs from the presence of helpers have been uncovered. However, until now, the factors that determine the type of assistance helpers provide and the responses of social pairs have not been well illustrated. We examined the contribution of helpers to cooperative groups and the relevant responses of dominant pairs in the azure‐winged magpie, Cyanapica cyana, which breeds on the Tibetan Plateau. We used the capture‐mark‐recapture method to identify helpers. Results showed that helpers were mostly the yearling sons of dominant pairs. They mainly contributed to the cooperative group in three ways, courtship‐feeding the incubation female, provisioning the brood, and defending the nest. For responses of dominant pairs, we unexpectedly found that clutch size was not influenced by the presence of helpers at the nest. However, cooperative groups had higher brood feeding rates than biparental nests and their feeding pattern also differed to that of the latter. Consequently, nestlings in cooperative groups had larger fledging body mass than that in biparental nests. By examining reasons for nest failure, we revealed that conspecific nest‐raiding contributed to more nest failure than any other natural predators. Because of the contribution of helpers in defending against both predators and conspecific nest‐raiders, cooperative groups had higher survival rate than biparental nests. Thus, our findings suggest that in a highly‐clumped nesting pattern, factors concerning the risk of nest predation, rather than that influencing food supply, play an important role in determining helper effects and responses of aided dominant pairs. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-18T04:22:57.886163-05:
      DOI: 10.1111/jav.00783
       
  • Comparing inferences of solar geolocation data against
           high‐precision GPS data: annual movements of a double‐tagged
           black‐tailed godwit
    • Authors: Eldar Rakhimberdiev; Nathan R. Senner, Mo A. Verhoeven, David W. Winkler, Willem Bouten, Theunis Piersma
      Abstract: Annual routines of migratory birds inferred from archival solar geolocation devices have never before been confirmed using GPS technologies. A female black‐tailed godwit Limosa limosa limosa captured on the breeding grounds in The Netherlands in 2013 and recaptured in 2014 was outfitted with both an Intigeo geolocator and an UvA‐BiTS GPS‐tracker. The GPS positions show that, after its breeding season in 2013, the godwit flew 2035 km nonstop from The Netherlands to southern Spain. It then spent the entire nonbreeding season in the southern part of the Iberian Peninsula before returning to The Netherlands the following spring, stopping for 7 days in the delta of the Ebro River in Spain, and again for a day in central Belgium. To compare the geolocation and GPS data, we analysed the geolocation data with two open‐source software packages: one using a threshold method (GeoLight) and the other a template‐fit approach (FLightR). Estimates using GeoLight, on average, deviated from the individual's true position by 495.5 ± 1031.2 km (great circle distance with equinoxes excluded), while FLightR estimates deviated by 43.3 ± 51.5 km (great circle distance with equinoxes included). Arrival and departure schedules estimated by FLightR were within 12 hours of those determined by the GPS tracker, whereas GeoLight's estimates were less precise. For the analysed track, FLightR represents an improvement over GeoLight; if true for other species and conditions, FLightR will hopefully help establish more precise and accurate uses of geolocation data in tracking studies. To aid future improvements in the analysis of solar geolocation data, we also provide the GPS and geolocation data files together with our R scripts as supplementary material. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-14T07:52:41.136478-05:
      DOI: 10.1111/jav.00891
       
  • Foraging behaviour and fuel accumulation of capital breeders during spring
           migration as derived from a combination of satellite‐ and
           ground‐based observations
    • Abstract: The migration strategy of many capital breeders is to garner body stores along the flyway at distinct stopover sites. The rate at which they can fuel is likely to be strongly influenced by a range of factors, such as physiology, food availability, time available for foraging and perceived predation. We analysed the foraging behaviour and fuel accumulation of pink‐footed geese, an Arctic capital breeder, at their mid‐ flyway spring stopover site and evaluated to what extent their behaviour and fuelling were related to physiological and external factors and how it differed from other stopovers along the flyway. We found that fuel accumulation rates of geese at the mid‐flyway site were limited by habitat availability rather than by digestive constraints. However, as the time available for foraging increased over the stopover season, geese were able to keep constant fuelling rate. Putting this in perspective, geese increased their daily net energy intake along the flyway corresponding to the increase in time available for foraging. The net energy intake per hour of foraging remained the same. Geese showed differences in their reaction to predators/disturbance between the sites, taking higher risks particularly at the final stopover site. Hence, perceived predation along the flyway may force birds to postpone the final fuel accumulation to the last stopover along the flyway. Flexibility in behaviour appears to be an important trait to ensure fitness in this capital breeder. Our findings are based on a new, improved method for estimating fuel accumulation of animals foraging in heterogeneous landscapes based on data obtained from satellite telemetry and habitat specific intake rates. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-14T07:52:24.785351-05:
      DOI: 10.1111/jav.00899
       
  • A rare study from the wintering grounds provides insight into the costs of
           malaria infection for migratory birds
    • Abstract: Malaria parasites can have strong effects on the population dynamics and evolution of migratory bird species. In many species, parasite transmission occurs on the wintering grounds, but studies to determine the consequences of infection have taken place during the breeding season, when malaria parasites circulate at chronic levels. We examined the predictors of malarial infections for great reed warblers during the northern winter in Africa, where active parasite transmission is thought to occur and naïve individuals experience acute infections. Counter to expectations, we found that winter infection intensities were lower than those encountered on the breeding grounds. One potential explanation is that reduced immune function during breeding allows parasites to persist at higher chronic intensities. We found no relationships between the incidence or intensity of infection on condition (as measured by scaled mass index, plasma metabolites, and feather corticosterone), spring migration departure dates, or home range sizes. We also tested a prediction of the Hamilton‐Zuk hypothesis and found that male ornament (song) quality was unrelated to parasitic infection status. Overall, our results provide the first evidence that long‐distance migrants captured on their wintering grounds are in the chronic stage of infection, and suggest that winter studies may fare no better than breeding studies at determining the costs of acute malarial infection for great reed warblers. This article is protected by copyright. All rights reserved.
      PubDate: 2016-01-14T07:52:08.420289-05:
      DOI: 10.1111/jav.00870
       
  • Female collared flycatchers choose neighbouring and older extra‐pair
           partners from the pool of males around their nests
    • Authors: Anais Edme; Pavel Munclinger, Milos Krist
      Abstract: Extra‐pair copulation is common among passerine birds. Females might engage in this behavior to obtain direct or indirect benefits. They may choose extra‐pair males with larger ornaments, especially if they are costly to produce. Here we studied extra‐pair paternity in the collared flycatcher. Genetic analysis allowed us to identify the presence or absence of extra‐pair young in the focal nests, and to identify extra‐pair fathers. We also identified potential males available as extra‐pair sires around the nests of females who had extra‐pair young. First, we tested the relationship between paternity in own nest and ornament size (wing patch and/or forehead patch), morphological traits and age of social males and females. Second, we compared the same suite of traits among social mates, extra‐pair males and all potential extra‐pair mates. Finally, we investigated the effect of the size of ornaments on the distance between the social nest and that of nest the extra‐pair father. Contrary to our prediction, males with larger ornaments and longer wings lost more paternity in their nests. We also found that early breeders lost less paternity in their nests. Extra‐pair males were older and had longer wings than social and potential extra‐pair males. Females mainly obtained extra‐pair mates near their nests but the distance did not vary according to ornamentation. These results could potentially be explained by differences in mate guarding strategy as older males may be more experienced in guarding their mate and attract other females more easily. More data about mate guarding and prospecting are needed to increase our understanding of mechanisms underlying the extra‐pair paternity in birds.
      PubDate: 2016-01-14T07:51:52.848313-05:
      DOI: 10.1111/jav.00839
       
  • Chemical labels differ between two closely related shearwater taxa
    • Abstract: Chemical signals may be the basis of interspecific recognition and speciation in many animals. To test whether a chemical label allowing recognition between closely related species exists in seabirds, we investigated two closely related taxa breeding sympatrically at some localities: Cory's and Scopoli's shearwaters. Procellariiform seabirds are ideal for this study because they have a well‐developed olfactory system and unequalled associated capabilities among birds. We analysed and compared the relative volatile compounds composition of the uropygial gland secretions of Cory's and Scopoli's shearwaters. As the volatile components from uropygial secretions might also provide some critical eco‐chemical information about population origin and sex, we also examined variations in the volatile compounds between populations and sexes in Cory's shearwater. The chemical data were obtained using gas chromatography–mass spectrometry techniques looking for the presence of these three particular labels: species, population and gender. We found diagnostic differences in uropygial secretions between the two species of shearwaters and smaller but significant variation between populations of Cory's shearwater in the Atlantic. No significant differences were observed between males and females. Individuals might thus use the chemical variation between species to recognize and mate with conspecifics, especially at localities where both species breed sympatrically. Geographical variation in chemical composition of uropygial secretions suggests that selective forces might vary according with locations, and might provide a key in the species recognition. Further behavioural bioassays are needed to determine whether or not these species labels are signals allowing reproductive isolation between these two taxa. Finally, one of the aims of our study was to test easier methods than freezing for storing uropygial gland secretions in the field. We describe here a new possibility for the storage of uropygial secretion samples at ambient temperature in the field, providing an alternative, simple protocols for the sampling of avian chemosignals. This article is protected by copyright. All rights reserved.
      PubDate: 2015-12-23T08:11:14.959536-05:
      DOI: 10.1111/jav.00853
       
  • Speciation in mountain refugia: phylogeography and demographic history of
           the pine siskin and black‐capped siskin complex
    • Abstract: Following Pleistocene glacial maxima, species that adapted to temperate climates in low‐latitude refugia had to modify their ranges as climate changed, expanding either latitudinally towards the poles, or altitudinally to higher elevations in mountainous regions. Within just a few thousand years, populations taking alternative routes during interglacials became isolated from each other and subjected to different selection pressures, often leading to lineage divergence and speciation. The pine siskin (Spinus pinus) is a common and widespread songbird showing relative phenotypic uniformity across the North American continent. One exception is the subspecies found in the highlands of northern Central America (S. p. perplexus), which shows marked differentiation in plumage color and shares some traits with the endemic and partly sympatric black‐capped siskin (S. atriceps), suggesting potential introgression or even a hybrid origin of perplexus. Relationships and species limits among pinus, perplexus and atriceps have been controversial for decades. We provide new molecular evidence to help resolve the evolutionary history of the group. Phylogenetic analysis of mitochondrial DNA and nuclear intron sequences revealed three distinct lineages within the complex, corresponding to: (1) S. pinus individuals from Canada through central Mexico (S. p. pinus and S. p. macropterus), (2) individuals from the highlands of Guatemala and Chiapas (S. p. perplexus), and (3) S. atriceps. Pine siskins across North America show evidence of a recent postglacial population expansion and extremely low levels of diversity and structure. In contrast, S. p. perplexus shows evidence of demographic stasis, reflecting long‐term isolation and restricted dispersal. Marked and diagnostic genetic differences among the three lineages in mtDNA and at least one intron, suggest that a hybrid origin of S. p. perplexus is unlikely, yet some degree of introgression between S. p. perplexus and S. atriceps cannot be ruled out in localities where they occur in sympatry. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-22T23:59:43.108293-05:
      DOI: 10.1111/jav.00814
       
  • Cuckoo parasitism in a cavity nesting host: near absent
           egg‐rejection in a northern redstart population under heavy apparent
           (but low effective) brood parasitism
    • Authors: Robert L. Thomson; Jere Tolvanen, Jukka T. Forsman
      Abstract: Brood parasite ‐ host systems continue to offer insights into species coevolution. A notable system is the redstart Phoenicurus phoenicurus parasitized by the “redstart‐cuckoo” Cuculus canorus gens. Redstarts are the only regular cuckoo hosts that breed in cavities, which challenges adult cuckoos in egg laying and cuckoo chicks in host eviction. We investigated parasitism in this system and found high overall parasitism rates (31.1% of 360 redstart nests), but also that only 33.1% of parasitism events (49 of 148 eggs) were successful in laying eggs into redstart nest cups. The majority of cuckoo eggs were mislaid and found on the rim of the nest; outside the nest cup. All available evidence suggests these eggs were not ejected by hosts. The effective parasitism rate was therefore only 12.8% of redstart nests. Redstarts responded to natural parasitism by deserting their nests in 13.0% of cases, compared to desertion rates of 2.8% for non‐parasitized nests. Our egg parasitism experiments found low rates (12.2%) of rejection of artificial non‐mimetic cuckoo eggs. Artificial mimetic and real cuckoo eggs added to nests were rejected at even lower rates, and were always rejected via desertion. Under natural conditions, only 21 cuckoo chicks fledged of 150 cuckoo eggs laid. Adding to this low success, is that cuckoo chicks are sometimes unable to evict all host young, and were more likely to die as a result compared to cuckoo chicks reared alone. This low success seems to be mainly due to the cavity nesting strategy of the redstart which is a challenging obstacle for the cuckoo. The redstart‐cuckoo system appears to be a fruitful model system and we suggest much more emphasis should be placed on frontline defences such as nest site selection strategies when investigating brood parasite‐host coevolution. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-22T23:59:15.215626-05:
      DOI: 10.1111/jav.00915
       
  • Causes and Characteristics of Reverse Bird Migration: an Analysis Based on
           Radar, Radio Tracking and Ringing at Falsterbo, Sweden
    • Abstract: That birds migrate in the reverse direction of the expected is a phenomenon of regular occurrence which has been observed at many sites. Here we use three different methods; tracking radar, radiotelemetry and ringing, to characterize the flights of these reverse migrants and investigate possible causes of reverse migration of nocturnally migrating passerines during autumn migration at Falsterbo peninsula, Sweden. Using these different methods we investigated both internal factors, such as age and fuel load, and external factors such as weather variables, competition and predation risk. Birds flying in the reverse direction were more likely to be lean and to be juveniles. Reverse migration was also more common with overcast skies and winds with north and east components. We did not find any effect of temperature, visibility, number of migrating sparrowhawks, or the total number of ringed birds at the site on the day of departure. We found that reverse migration is characterized by slower flight speeds (airspeed) at high altitudes and that it takes place later in the night than forward migration. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-22T23:57:48.825655-05:
      DOI: 10.1111/jav.00707
       
  • Dispersal of fungi spores by non‐specialized flower‐visiting
           birds
    • Abstract: Birds are important biotic dispersers of a wide range of propagules. Fungi spores are mainly dispersed by wind. Nevertheless there are several animals known to disperse fungi spores, which might be particularly important if spores are they delivered to particularly favourable sites i.e. directed dispersal. This may be especially important for fungi that require specific microsites such as flowers. We sampled birds for the presence of fungi spores and pollen grains during one year at two forest sites in central Portugal. We found that out of the 894 birds sampled, 131 individuals from 11 species carried spores from at least 6 morphological types, mainly during winter. The great majority of birds found to carry fungi spores was also found to carry pollen grains, suggesting that they were feeding on flowers which are the main origin of the spores. This co‐dispersion of pollen and fungi spores suggest that the latter are not randomly dispersed on the environment, but are likely to have an increased probability of being deposited on flowers propitious to fungi development. Our results suggest that directed dispersal of fungi by flower‐visiting birds might by a common and under‐appreciated phenomenon with potentially important ecological, biogeographic and even economic outcomes. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-22T23:56:50.353519-05:
      DOI: 10.1111/jav.00806
       
  • Eggshell biliverdin concentration does not sufficiently predict eggshell
           coloration
    • Authors: Michael W. Butler; Haleigh S. Waite
      Abstract: Avian eggshell coloration may have arisen due to selection on the biological, chemical, or physical properties of the pigments embedded within the eggshell, or due to selection on the coloration that emerges due to pigment deposition. Within both hypothetical frameworks, pigment‐based eggshell coloration would be related to metrics of egg quality; however, no one has evaluated the relative strength of coloration and pigment concentration in predicting egg quality. Here, we examined 66 European starling (Sturnus vulgaris) eggs and quantified eggshell biliverdin concentration (an antioxidant that produces the eggshell's blue coloration) and used 28 different coloration metrics derived from both photographic and spectrophotometric data. We also measured egg size, eggshell thickness, concentration of carotenoids in the yolk, and concentration of lysozyme in the albumen to capture variation in egg quality. We found that throughout the laying sequence, biliverdin concentration increased while eggshell thickness, yolk carotenoid concentration, and lysozyme concentration in the albumen all decreased, but this variation was not captured by any eggshell color metric. Both eggshell coloration and biliverdin concentration were negatively associated with yolk carotenoid concentration, but only eggshell biliverdin concentration was negatively associated with yolk mass. Lastly, biliverdin concentration explained, at most, only 46% of the variation for all eggshell coloration metrics. Our results suggest biliverdin concentration is a better predictor of egg quality than egg coloration in European starlings, supporting the hypothesis that eggshell pigment concentration per se may be the target of selection. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-19T08:14:03.409965-05:
      DOI: 10.1111/jav.00842
       
  • Directed flight and optimal airspeeds: homeward‐bound gulls react
           flexibly to wind yet fly slower than predicted
    • Abstract: Birds in flight are proposed to adjust their body orientation (heading) and airspeed to wind conditions adaptively according to time and energy constraints. Airspeeds in goal‐directed flight are predicted to approach or exceed maximum‐range airspeeds, which minimize transport costs (energy expenditure per unit distance) and should increase in headwinds and crosswinds. Diagnosis of airspeed adjustment is however obscured by uncertainty regarding birds’ goal‐directions, transport costs, interrelations with orientation strategy and the attainability of predicted behaviour. To address these issues, we tested whether gulls minimized transport costs through adjustment of airspeed and heading to wind conditions during extended inbound flight over water (180‐360 km) to their breeding colony, and introduce a methodology to assess transport (energy) efficiency given wind conditions. Airspeeds, heading, flight mode and energy expenditure were estimated using GPS tracking, accelerometer and wind data. Predicted flight was determined by simulating each trip according to maximum‐range airspeeds and various orientation strategies. Gulls employed primarily flapping flight (93%), and negotiated crosswinds flexibly to exploit both high altitude tailwinds and coastal soaring opportunities. We demonstrate that predicted airspeeds in heavy crosswinds depend strongly on orientation strategy and presumed preferred direction. Measured airspeeds increased with headwind and crosswind similarly to maximum‐range airspeeds based on full compensation for wind drift, yet remained ~30% lower than predicted by all strategies, resulting in slower and 30‐35% costlier flight. Interestingly, more energy could be saved through adjustment of airspeed (median 40%) than via orientation strategy (median 4%). Therefore, despite remarkably flexible reaction to wind at sea, these gulls evidently minimized neither time nor energy expenditure. However, airspeeds were possibly over‐predicted by current aerodynamic models. This study emphasizes the importance of accounting for orientation strategy when assessing airspeed adjustments to wind and indicates that either the cost or adaptive ‘currency’ of extended flight among gulls may require revision. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-19T08:13:48.98832-05:0
      DOI: 10.1111/jav.00828
       
  • The migration of the great snipe Gallinago media: intriguing variations on
           a grand theme
    • Abstract: The migration of the great snipe Gallinago media was previously poorly known. Three tracks in 2010 suggested a remarkable migratory behaviour including long and fast overland non‐stop flights (Klaassen et al. 2011). Here we present the migration pattern of Swedish male great snipes, based on 19 individuals tracked by light‐level geolocators in four different years. About half of the birds made stopover(s) in northern Europe in early autumn. They left the breeding area 15 days earlier than those which flew directly to sub‐Sahara, suggesting two distinct autumn migration strategies. The autumn trans‐Sahara flights were on average 5500 km long, lasted 64 h, and were flown at ground speeds of 25 m s‐1 (90 km h‐1). The arrival in the Sahel zone of West Africa coincided with the wet season there, and the birds stayed for on average three weeks. The birds arrived at their wintering grounds around the lower stretches of the Congo River in late September and stayed for seven months. In spring the great snipes made trans‐Sahara flights of similar length and speed as in autumn, but the remaining migration through eastern Europe was notably slow. All birds returned to the breeding grounds within one week around mid‐May. The annual cycle was characterized by relaxed temporal synchronization between individuals during the autumn‐winter period, with maximum variation at the arrival in the wintering area. Synchronization increased in spring, with minimum time variation at arrival in the breeding area. This suggests that arrival date in the breeding area is under strong stabilizing selection, while there is room for more flexibility in autumn and arrival to the wintering area. The details of the fast non‐stop flights remain to be elucidated, but the identification of the main stopover and wintering areas is important for future conservation work on this red‐listed bird species. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-17T23:17:10.153632-05:
      DOI: 10.1111/jav.00829
       
  • Evaluation of two methods for minimally invasive peripheral body
           temperature measurement in birds
    • Abstract: Body temperature (Tb) is a valuable parameter when assessing the physiological state of animals, but its widespread measurement is often constrained by methods that are invasive or require frequent recapture of animals. Alternatives based on automated remote sensing of peripheral Tb show promise, but little is known about their strengths and limitations. We measured peripheral Tb in great tits (Parus major L.) with subcutaneously implanted passive integrated transponders (PIT tags) and externally attached radio transmitters to determine repeatability of measurements, sensitivity of each method to variation in ambient temperature (Ta) and wind speed, the relationship between methods, and their ability to capture circadian variation in Tb. Repeatability of measurements by radio transmitters was high (> 80%) when readings were taken within 20 min, but reduced to 16% when measures were spaced 3.5 h apart. PIT tag data for the 3.5 h interval were more repeatable (33%) and less variable (cv). Data were affected by Ta with a stronger effect on the externally attached transmitters, but the influence of wind speed was small for both methods. There was a significant positive relationship between transmitter‐ and PIT tag temperature during both days and nights.. Both methods were equally suited to detect diel changes in peripheral Tb. However, transmitters offered longer detection distance and better temporal resolution. These qualities should be considered when deciding how to collect Tb data remotely. If properly deployed, both methods allow measurement of peripheral Tb over a wide range of natural systems and conditions in small, free‐ranging, birds. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-14T05:36:59.960872-05:
      DOI: 10.1111/jav.00845
       
  • Nest as an extended phenotype signal of female quality in the great reed
           warbler
    • Abstract: Extended phenotypes with signalling function are mostly restricted to animal taxa that use construction behaviour during courtship displays. However, they can be used also as post‐mating signals of mate quality, allowing individuals to obtain reliable information about their partners. Nest size may have such a signalling function and a lot of indirect evidence supports this view. However, direct evidence based on an experimental approach is still widely missing. Here we test the role of nest size in post‐mating signalling of mate quality in the great reed warbler (Acrocephalus arundinaceus), a passerine with female‐restricted nest‐building behaviour. Based on observational data, clutch size, nestling weight, brood size and fledglings’ propensity to return to their natal site positively correlated with nest size. Moreover, we experimentally enlarged great reed warbler nests to investigate whether this manipulation affects male investment in feeding. We found that males fed their nestlings significantly more intensively on enlarged nests than those on control nests. This suggests that nest size in this species serves as a signal of female quality or willingness to invest in reproduction and that it pays males to enhance their feeding effort according to this signal. Thus, we provide convincing evidence that animal communication takes place through the extended phenotypes and that post‐mating signalling of quality is not restricted only to males, but may function equally well in females. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-14T05:16:06.538701-05:
      DOI: 10.1111/jav.00700
       
  • The effects of heterospecifics and climatic conditions on incubation
           behavior within a mixed‐species colony
    • Authors: Peter S. Coates; Brianne E. Brussee, Roger L. Hothem, Kristy H. Howe, Michael L. Casazza, John M. Eadie
      Abstract: Parental incubation behavior largely influences nest survival, a critical demographic process in avian population dynamics, and behaviors vary across species with different life history breeding strategies. Although research has identified nest survival advantages of mixing colonies, behavioral mechanisms that might explain these effects is largely lacking. We examined parental incubation behavior using video‐monitoring techniques on Alcatraz Island, California, of black‐crowned night‐heron (Nycticorax nycticorax; hereinafter, night‐heron) in a mixed‐species colony with California gulls (Larus californicus) and western gulls (L. occidentalis). We first quantified general nesting behaviors, incubation constancy, and nest attendance, and a suite of specific nesting behaviors (i.e., inactivity, vigilance, preening, and nest maintenance) with respect to six different daily time periods. We employed linear mixed effects models to investigate environmental and temporal factors as sources of variation in incubation constancy and nest attendance using 211 nest days across three nesting seasons (2010–2012). We found incubation constancy (percent of time on the eggs) and nest attendance (percent of time at the nest) were lower for nests that were located
      PubDate: 2015-11-13T01:06:45.008553-05:
      DOI: 10.1111/jav.00900
       
  • Urban living alters moult dynamics in a passerine
    • Authors: Sydney F. Hope; Frank A. Stabile, Luke K. Butler
      Abstract: Urbanization and habitat fragmentation can alter the timing of life history events, potentially leading to phenological mismatches, carryover effects, and fitness costs. Whereas urbanization and fragmentation are known to alter important aspects of breeding in many bird species, little is known about the effects of urbanization and habitat fragmentation on moult. To investigate the effects of urbanization and fragmentation on the annual moult, we compared the moult dynamics (onset, duration, and intensity) of urban, fragmented forest, and contiguous forest populations of the Carolina Chickadee, a North American resident passerine that moults once per year immediately following the breeding season. Over three years, moult dynamics were similar in contiguous and fragmented forest populations, but wing moult started significantly earlier, and onset of moult varied less among years, in urban chickadees than in forest chickadees (fragmented and contiguous habitats pooled). Duration of wing moult did not differ between urban and forest populations, but urban birds moulted significantly fewer feathers simultaneously during peak moult, suggesting that individual feathers grew more rapidly. Our results show that urban living alters critical aspects of moult dynamics in a widespread songbird. Given the importance of moult dynamics for fitness during subsequent life history stages, and the large number of songbird species inhabiting urban areas, these results reveal previously unrecognized and potentially costly carryover effects of urban living on songbirds. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-13T01:02:53.291127-05:
      DOI: 10.1111/jav.00866
       
  • Carotenoid‐based plumage colouration is predicted by age and
           parasites in the male European serin
    • Authors: Sandra Trigo; Paulo Gama Mota
      Abstract: A fundamental assumption of theories on the evolution of sexual signals is that they should be costly to produce in order to honestly signal the quality of the sender. The expression of carotenoid‐based plumage signals is considered to be condition‐dependent, due to the role of carotenoids functioning as pigments and as health modulators. We assessed carotenoid‐based plumage colouration in relation to male condition in a free living population of male European serins, Serinus serinus during the breeding season. Male serins were trapped for morphometric and colouration measurements, during a four‐year field study, in order to evaluate the signalling value of colouration in relation to body condition and parasites level. We compared two different forms of colour quantification based on spectral data ‐ the most commonly used tristimulus colour variables and physiological models of avian colour vision ‐ and found that they were highly correlated for this species. We investigated the signalling value of male plumage colouration and it was found to be related to age and ectoparasite load. Plumage double cone and patch size were negatively related to parasites level, whereas SWS ratio was positively related to parasites and age. Colouration was also related with the time since moult. Our results indicate that the colour expression of serin's plumage is age dependent and is related, in complex ways, with the ability to cope with parasitic infection. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-13T00:46:40.472758-05:
      DOI: 10.1111/jav.00795
       
  • Nest shape explains variation in sexual dichromatism in New World
           blackbirds
    • Authors: Jonathan P. Drury; Nathan Burroughs
      Abstract: Following Charles Darwin, research on sexual dichromatism has long focused on sexual selection driving ornamentation in males. However, Alfred Russel Wallace proposed another explanation—that dichromatism evolves as a result of selection favoring crypsis in incubating females. Many recent studies suggest that evolutionary changes in sexual dichromatism often result from changes in female, in addition to male, plumage, yet the evolutionary mechanisms driving changes in female plumage remain largely unexplained. To test Wallace's hypothesis, we examined variation in sexual dichromatism and nest shape, a proxy for predation risk, among New World blackbirds (Aves: Icteridae). Phylogenetic models reveal an evolutionary correlation between sexual dichromatism and nest exposure. Specifically, we found that transitions in monochromatic lineages with exposed nests toward either concealed nests or dichromatism were common. Although this evidence supports Wallace's hypothesis that female incubation leads to selection for crypsis or concealment, we also found that transitions to monomorphism were common, even in lineages with exposed nests—a result suggestive of a role for positive selection on female ornamentation. These patterns of plumage evolution support a growing body of work emphasizing the importance of developing and testing hypotheses to explain evolutionary changes in female, as well as male, ornamentation. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-13T00:44:46.119868-05:
      DOI: 10.1111/jav.00757
       
  • A trade‐off between overheating and camouflage on shorebird eggshell
           colouration
    • Abstract: In ground‐nesting birds egg colour and appearance may have evolved due to opposite selection pressures. Pigmentation and spottiness make the eggs darker and have been suggested to improve camouflage. However darker and more spotted eggs may reach higher temperatures when not attended by adults and receiving direct sunlight, which may be lethal for embryos. Some authors suggested that this trade‐off may not exist because eggshell pigments mainly reflect in the infrared region of the solar spectrum, but have not considered that wavelengths in the visible part of the spectrum may also contribute to overheating. To test the occurrence of a trade‐off between camouflage and overheating of eggs, we took digital images to analyse colour and camouflage in 93 nests of four shorebird species (two stilts and two plovers) in two regions (tropical and mediterranean sites). We predicted that these species (closely related) may have evolved different eggshell designs depending on solar radiation, which is supposed to be stronger in the Tropics. To record egg temperatures, we placed Japanese quail eggs in natural nests of shorebirds, and registered temperatures using a datalogger. We found that darker and more spotted eggs reached higher temperatures than lighter ones, and that after controlling for environmental temperatures, eggs overheated more in the Tropics, likely because of a more intense solar radiation. We also found that tropical shorebirds’ eggshells have darker spots and lighter backgrounds. Overall, darker eggs were better camouflaged. Taken together, our results show that the benefits of increasing pigmentation of eggshell backgrounds and spottiness for a better camouflage are counteracted by the increased risks of overheating when eggs remain exposed to direct solar radiation.
      PubDate: 2015-11-03T22:21:44.355031-05:
      DOI: 10.1111/jav.00736
       
  • The role of western Mediterranean islands in the evolutionary
           diversification of the Spotted Flycatcher (Muscicapa striata), a
           long‐distance migratory passerine species
    • Abstract: We investigated the evolutionary history of the Spotted Flycatcher (Muscicapa striata), a long distance migratory passerine having a widespread range, using mitochondrial markers and nuclear introns. Our mitochondrial results reveal the existence of one insular lineage restricted to the western Mediterranean islands (Balearics, Corsica, Sardinia) and possibly to the Tyrrhenian coast of Italy that diverged from the mainland lineages around 1 Mya. Mitochondrial genetic distance between insular and mainland lineages is around 3.5%. Limited levels of shared nuclear alleles among insular and mainland populations further support the genetic distinctiveness of insular spotted flycatchers with respect to their mainland counterparts. Moreover, lack of mitochondrial haplotypes sharing between Balearic birds (M. s. balearica) and Corso‐Sardinian birds (M. s. tyrrhenica) suggest the absence of recent matrilineal gene flow between these two insular subspecies. Accordingly, we suggest that insular Spotted Flycatchers could be treated as one polytypic species (Muscicapa tyrrhenica Schiebel, 1910) that differs from M. striata in morphology, migration, mitochondrial and nuclear DNA and comprises two subspecies (the nominate and M. t. balearica, von Jordans, 1913) that diverged recently phenotypically and in mitochondrial DNA and but still share the same nuclear alleles. This study provides an interesting case‐study illustrating the crucial role of western Mediterranean islands in the evolution of a passerine showing high dispersal capabilities. Our genetic results highlight the role of glacial refugia of these islands that allowed initial allopatric divergence of insular populations. We hypothesize that differences in migratory and breeding phenology may prevent any current gene flow between insular and mainland populations of the Spotted Flycatcher that temporarily share the same insular habitats during the spring migration. This article is protected by copyright. All rights reserved.
      PubDate: 2015-11-02T07:09:24.641622-05:
      DOI: 10.1111/jav.00859
       
  • First geolocator tracks of Swedish red‐necked phalaropes reveal the
           Scandinavia‐Arabian Sea connection
    • Authors: Rob S. A. Bemmelen; Johannes Hungar, Ingrid Tulp, Raymond H. G. Klaassen
      Abstract: We studied migration and wintering patterns of a wader with a pelagic lifestyle during the non‐breeding period, the red‐necked phalarope Phalaropus lobatus. Using light‐level geolocation, we obtained three full annual tracks and one autumn migration track of male red‐necked phalaropes caught during breeding in Scandinavia. These tracks confirmed expectations that individuals from the Scandinavian population winter in the Arabian Sea. Migration was accomplished in two to four migration leaps, staging for a few days in the Gulf of Finland (autumn) or the southern Baltic Sea (spring) and for up to a month in or near the Black and Caspian Sea (autumn and spring). In addition, travel speeds suggested that only the flights between the Baltic and Black/Caspian Sea are non‐stop, and thus the birds seem to make additional short stops during the other flights. Stopover time in the Black/Caspian Sea is only 8–10 d in spring but up to 36 d in autumn, which is longer than expected if only used for pre‐migratory fattening to cover the ca 2000 km to the Gulf of Oman. After entering the Arabian Sea via the Gulf of Oman, birds dispersed over the entire presumed winter range. Winter movements appear to correspond to the spatio‐temporal patterns in primary production linked to seasonally changing monsoon winds. These are not only the first tracks of Scandinavian red‐necked phalaropes, but also the first seabird tracks in the Arabian Sea, one of the most productive and dynamic marine areas on the planet.
      PubDate: 2015-10-30T02:12:20.452544-05:
      DOI: 10.1111/jav.00807
       
  • Genetic markers validate using the natural phenotypic characteristics of
           
    • Authors: Sarah R. Hoy; Rachel E. Ball, Xavier Lambin, D. Philip Whitfield, Michael Marquiss
      Abstract: The recognition of individual animals is essential for many types of ecological research, as it enables estimates of demographic parameters such as population size, survival and reproductive rates. A popular method of visually identifying individuals uses natural variations in spot, stripe or scar markings. Although several studies have assessed the accuracy of these methods in mammals, crustaceans and fish, there have been few attempts to determine whether phenotypic characteristics are accurate when used for birds. Furthermore, even less is known about whether shed or moulted body parts can be reliably used to visually identify individuals. Here we assessed the accuracy of using phenotypic characteristics to identify avian individuals using a double‐marking experiment, whereby nine microsatellite genetic markers and natural markings on shed feathers were used to independently identify northern goshawks (Accipiter gentilis). Phenotypic and genetic identification of individuals was consistent in 94.4% (51/54) comparisons. Our results suggest that the phenotypic characteristics of shed feathers can be reliably used as a non‐invasive and relatively inexpensive technique to monitor populations of an elusive species, the northern goshawk, without having to physically re‐capture or re‐sight individuals. We posit that using natural markings on shed feathers will also be a reliable method of identifying individuals in avian species with similar phenotypic characteristics, such as other Accipiter species. This article is protected by copyright. All rights reserved.
      PubDate: 2015-10-28T21:27:47.286181-05:
      DOI: 10.1111/jav.00794
       
  • Does saline water consumption affect feeding and fuel deposition rate of a
           staging, long‐distance migrating passerine'
    • Authors: Ron Efrat; Gavriella Shani, Roee Gutman, Nir Sapir
      Abstract: To accomplish their enduring journeys, migrating birds accumulate fuel consisting mainly of lipids in stopover sites located throughout their migration routes. Fuel deposition rate (FDR) is considered a key parameter determining the speed of migration and thereby bird fitness, and recent studies have demonstrated the positive effects of fresh water consumption on the FDR of migrating blackcaps (Sylvia atricapilla). Sewage water reservoirs, characterized by higher water salinity than fresh water, were extensively built in different parts of the world and are used by birds during their travel, but their effects on wildlife and specifically on migrating birds have been largely overlooked thus far. We experimentally examined the effects of water salinity on blackcap FDR during migration. We captured birds in an autumn stopover site, transported them to the laboratory and provided them with fruits, mealworms and water of different salinity levels (0.3, 4.5 and 9‰ NaCl) for several days. We examined the effects of water salinity on the blackcaps’ diet, water consumption and FDR and found that FDR was mainly affected by fruit consumption rate and not by the water salinity levels. Water salinity nevertheless caused elevated water consumption as the birds consumed almost 3 times more saline water than fresh water per consumed fruit mass. Our work is the first to explore the consequences of saline water consumption on migrating passerines, specifically suggesting that anthropogenic alterations of habitats by sewage water treatment facilities may modulate bird nutrition and diet. This article is protected by copyright. All rights reserved.
      PubDate: 2015-10-28T21:26:05.898225-05:
      DOI: 10.1111/jav.00770
       
  • The Evolution of Sexually Dimorphic Tail Feathers Is Not Associated with
           Tail Skeleton Dimorphism
    • Authors: Ryan N. Felice; Patrick M. O'Connor
      Abstract: Sexual selection can influence the evolution of sexually dimorphic exaggerated display structures. Herein, we explore whether such costly ornamental integumentary structures evolve independently or if they are correlated with phenotypic change in the associated skeletal system. In birds, elongate tail feathers have frequently evolved in males and are beneficial as intraspecific display structures but impart a locomotor/energetic cost. Using the sexually dimorphic tail feathers of several passeriform species as a model system, we test the hypothesis that taxa with sexually dimorphic tail feathers also exhibit sexual dimorphism in the caudal skeleton that supports the muscles and integument of the tail apparatus. Caudal skeletal morphology is quantified using both geometric morphometrics and linear morphometrics across four sexually dimorphic passeriform species and four closely related monomorphic species. Sexual dimorphism is assessed using permutational MANOVA. Sexual dimorphism in caudal skeletal morphology is found only in those taxa that exhibit active functional differences in tail use between males and females. Thus, dimorphism in tail feather length is not necessarily correlated with the evolution of caudal skeletal dimorphism. Sexual selection is sufficient to generate phenotypic divergence in integumentary display structures between the sexes, but these change are not reflected in the underlying caudal skeleton. This suggests that caudal feathers and bones evolve semi‐independently from one another and evolve at different rates in response to different types of selective pressures. This article is protected by copyright. All rights reserved.
      PubDate: 2015-10-28T21:25:53.948942-05:
      DOI: 10.1111/jav.00801
       
  • Nesting success of native and introduced forest birds on the island of
           Kaua‘i
    • Authors: Ruby L. Hammond; Lisa H. Crampton, Jeffrey T. Foster
      Abstract: Forests of the Hawaiian archipelago are a global hotspot for conserving avian diversity and contain among the world's most imperiled species. Demographic studies are necessary to determine primary causes of Hawaiian forest bird population declines. We conducted research on the nesting success of multiple bird families on the island of Kaua‘i, allowing us to investigate the importance of factors related to breeding biology on forest bird declines at a community scale. Our study included two Hawaiian honeycreepers, ‘anianiau (Magumma parva) and ‘apapane (Himatione sanguinea), a native monarch flycatcher, Kaua‘i ‘elepaio (Chasiempis sclateri), and one introduced species, Japanese white‐eye (Zosterops japonicus). Data from 123 nests showed that nesting success ± SE, estimated using program MARK, was low for ‘apapane (0.23 ± 0.10), but did not vary substantially among our other study species (‘anianiau = 0.56 ± 0.09, Kaua‘i ‘elepaio = 0.63 ± 0.08, Japanese white‐eye = 0.52 ± 0.11). Causes of nest loss for 51 nest failures included nest predation (43%), unknown (25%), empty after termination with no signs of nest predation (e.g., eggshell or chick remains in nest, disheveled nest) (24%), and abandoned clutch or brood (4% each). Kaua‘i ‘elepaio suffered more than twice as many nest losses to predation compared to our other study species, but also had the highest nesting success; and, ‘apapane suffered least to nest predation, but had the lowest nesting success. Further, rates of nesting success derived in our study were relatively high compared to multi‐species studies in mainland tropics. Therefore, although nest predation accounted for the greatest proportion of nest failures, it may not be a cause of forest bird population declines in our system. We suggest that future demographic studies focus on post‐fledgling, juvenile, and adult survival, in addition to the importance of double‐brooding and renesting attempts on annual reproductive success. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-25T02:05:53.175644-05:
      DOI: 10.1111/jav.00763
       
  • Shaped by uneven Pleistocene climate: mitochondrial phylogeographic
           pattern and population history of White Wagtail Motacilla alba (Aves:
           Passeriformes)
    • Abstract: We studied the phylogeography and population history of the White Wagtail Motacilla alba, which has a vast breeding range, covering areas with different Pleistocene climatic histories. The mitochondrial NADH dehydrogenase subunit II gene (ND2) and Control Region (CR) were analyzed for 273 individuals from 45 localities. Our data comprised all nine subspecies of White Wagtail. Four primary clades were inferred (M, N, SW and SE), with indications of M. grandis being nested within M. alba. The oldest split was between two haplotypes from the endemic Moroccan M. a. subpersonata (clade M) and the others, at 0.63–0.96 Mya; other divergences were at 0.31–0.38 Mya. The entire differentiation falls within the part of the Pleistocene characterized by Milankovitch cycles of large amplitudes and durations. Clade N was distributed across the northern Palearctic; clade SW in southwestern Asia plus the British Isles and was predicted by Ecological niche models (ENMs) to occur also in Central and South Europe; and clade SE was distributed in Central and East Asia. The deep divergence within M. a. subpersonata may reflect retention of ancestral haplotypes. Regional differences in historical climates have had different impacts on different populations: clade N expanded after the last glacial maximum (LGM), whereas milder Pleistocene climate of East Asia allowed clade SE a longer expansion time (since MIS 5); clade SW expanded over a similarly long time as clade SE, which is untypical for European species. ENMs supported these conclusions in that the northern part of the Eurasian continent was unsuitable during the LGM, whereas southern parts remained suitable. The recent divergences and poor structure in the mitochondrial tree contrasts strongly with the pronounced, well defined phenotypical differentiation, indicating extremely fast plumage divergence. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-24T07:55:22.544234-05:
      DOI: 10.1111/jav.00826
       
  • Integrative taxonomy reveals Europe's rarest songbird species, the Gran
           Canaria Blue Chaffinch Fringilla polatzeki
    • Abstract: The conservation of endangered taxa often critically depends on accurate taxonomic designations. The status of the Gran Canaria population of the Blue Chaffinch Fringilla t. polatzeki has not been reevaluated since the early 1900s when this taxon was described as a subspecies and combined with the much more common Tenerife Blue Chaffinch F. t. teydea in a single species. We show that multiple diagnostic differences in plumage, songs, calls and morphometrics distinguish F. t. polatzeki from F. t. teydea. Preliminary playback experiments suggest that F. t. polatzeki is able to discriminate between songs of both taxa. Along with previously reported differences in mitochondrial DNA, these findings show that the blue chaffinches on Gran Canaria and Tenerife represent two highly distinctive species: F. polatzeki and F. teydea. Gran Canaria Blue Chaffinch is Europe's rarest passerine species and should be classified as Critically Endangered. Its long‐term survival in the wild currently depends on a very small (
      PubDate: 2015-09-24T07:52:23.814083-05:
      DOI: 10.1111/jav.00825
       
  • Do neophobia and dietary wariness explain ecological flexibility' An
           analysis with two seed‐eating birds of contrasting habits
    • Abstract: The neophobia threshold hypothesis (NTH) suggests that the acquisition and maintenance of a high behavioral and ecological flexibility in the evolutionary and adaptive history of a species is the consequence of lower levels of neophobia towards new micro‐habitats and of dietary wariness of novel foods. To test this idea we assessed the degree of neophobia and dietary wariness in two seed‐eating bird species with contrasting degrees of ecological flexibility that inhabit the central Monte desert (Argentina): a grass‐seed specialist, the many‐colored chaco‐finch, and a generalist feeder, the rufous‐collared sparrow. We expected that both species would exhibit neophobia and wariness when faced with new foraging opportunities but that the rufous‐collared sparrow would be less neophobic and less wary than the specialized many‐colored chaco‐finch. Experimental indicators of neophobia and dietary wariness included willingness to eat near novel objects and willingness to eat novel seeds, respectively. Both species showed similar levels of reluctance to novelty, although the sparrow could be slightly more reluctant than the finch. Contrary to our predictions, the sparrow was neither less hesitant nor faster or greedier than the finch. This experimental evidence does not support a negative relationship between neophobia / wariness and ecological flexibility in these two seed‐eating birds and it coincides with the growing evidence that challenges the NTH[0]. Some of our results provide support for the dangerous niche hypothesis (DNH), especially as the rufous‐collared sparrow, that feeds on more diverse and potentially dangerous food, showed higher levels of neophobia in some cases. Although the idea of neophobia and wariness being plausible causes of ecological specialization sounds attractive, the current situation calls for further research so that the causes of ecological flexibility in granivorous birds can be better understood. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-24T07:49:33.53167-05:0
      DOI: 10.1111/jav.00697
       
  • A reliable technique to quantify the individual variability of iridescence
           in birds
    • Abstract: The study of iridescence in birds emerged only recently, mainly due to the difficulty inherent in quantifying its directionality. Directionality restrains color perception to a limited angle and thereby causes drastic changes in brightness when an animal is in motion. Although a versatile goniometer for quantifying iridescence has been developed recently (Meadows et al. 2011), so far, it has only been applied to measuring the highly directional iridescence in a hummingbird species. Thus, the reliability of the goniometer for species displaying more common and less directional iridescent coloration has yet to be evaluated. Additionally, two important methodological aspects remain to be assessed before this apparatus can be used confidently: 1) whether directionality, which could be subject to sexual selection, can be quantified in a repeatable way; and 2) whether the apparatus gives more precise and accurate measurements than a less complex traditional method. Using feathers collected from 271 male tree swallows (Tachycineta bicolor) over two years, we found that the goniometer provided repeatable measurements of directionality across individuals and across three body regions, namely the crown, mantle and rump. The apparatus was also more repeatable than a traditional method involving a bifurcated probe and reduced a brightness bias associated with individual differences in barbule tilt. We strongly encourage researchers to invest in this methodological change considering the multiple advantages demonstrated and to quantify the directionality of iridescence as to unveil its role in signaling and sexual selection. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-24T07:48:03.613695-05:
      DOI: 10.1111/jav.00750
       
  • Complex migration and breeding strategies in an elusive bird species
           illuminated by genetic and isotopic markers
    • Abstract: Unlike the annual bi‐directional movements of over 200 bird species within the Palaearctic‐Afrotropical region, irregular movements such as irruptive migration with a low degree of philopatry are reported for a variety of species depending on highly seasonal and unpredictable resources. These flexible movements allow for itinerant breeding ‐ consecutive breeding attempts in two or more geographically different regions during the same annual reproductive cycle. In order to illuminate migratory and breeding strategies of the erratic wetland species Baillon's Crake (Zapornia pusilla) across the W‐Palaearctic –Afrotropical region, we used a set of six DNA microsatellites as well as δ2Hf values of individuals sampled at one African and four European breeding sites. We investigated the degree of genetic population structure within and among different sites and assigned individuals′ feathers of unknown origin to their probable moulting (hence breeding) site using a likelihood approach. We found three genetic clusters, differentiating into one “European” and two “African” populations. Connectivity between the sampling sites was probable as genetic “African” individuals were found in breeding conditions in Europe and vice versa. Likewise, assigned moulting locations based on δ2H isoscapes suggested trans‐continental movements as well as moulting and possibly breeding by the same individual both in African and European breeding grounds. Both isotopic and genetic data reveal the Baillon's Crake pursue a complex migration and breeding strategy, allowing as well for irruptive movements and itinerant breeding across the W‐Palaearctic‐Afrotropical region. However, a better knowledge about the species’ distribution as well as a more comprehensive data set, including samples from the Southern and Eastern boundaries of the distribution area would be necessary to improve the spatial resolution to the precision required to unambiguously infer migration directions and extent of exchange between African and European breeding grounds. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-24T07:46:24.406278-05:
      DOI: 10.1111/jav.00751
       
  • Double brooding and offspring desertion in the barn owl (Tyto alba)
    • Abstract: Many bird species produce two annual broods during a single breeding season. However, not all individuals reproduce twice in the same year suggesting that double brooding is condition‐dependent. In contrast to most raptors and owls, the barn owl (Tyto alba) produces two annual clutches in most worldwide distributed populations. Nevertheless, the determinants of double brooding are still poorly studied. We performed such a study in a Swiss barn owl population monitored between 1990 and 2014. The annual frequency of double brooding varied from 0 to 14% for males and 0 to 59% for females. The likelihood of double brooding was higher when individuals initiated their first clutch early rather than late in the season and when males had few rather than many offspring at the first nest. Despite the reproductive benefits of double brooding (single‐ and double‐brooded individuals produced 3.97±0.11 and 7.07±0.24 fledglings, respectively), double brooding appears to be traded off against offspring quality because at the first nest double‐brooded males produced poorer quality offspring than single‐brooded males. This might explain why females desert their first mate to produce a second brood with another male without jeopardizing reproductive success at the first nest. Furthermore, the reproductive cycle being very long in the barn owl (120 days from start of laying to offspring independence), selection may have favoured behaviours that accelerate the initiation of a second annual brood. Accordingly, half of the double‐brooded females abandoned their young offspring to look for a new partner in order to initiate the second breeding attempt, 9.48 days earlier than when producing the second brood with the same partner. We conclude that male and female barn owls adopt different reproductive strategies. Females have more opportunities to reproduce twice in a single season than males because mothers are not strictly required during the entire rearing period in contrast to fathers. A high proportion of male floaters may also encourage females to desert their first brood to re‐nest with a new male who is free of parental care duties. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-08T21:07:12.672176-05:
      DOI: 10.1111/jav.00800
       
  • Climate variability and the timing of spring raptor migration in eastern
           North America
    • Authors: Alexis R. Sullivan; David J. Flaspohler, Robert E. Froese, Daena Ford
      Abstract: Many birds have advanced their spring migration and breeding phenology in response to climate change, yet some long‐distance migrants appear constrained in their adjustments. In addition, bird species with long generation times and those in higher trophic positions may also be less able to track climate‐induced shifts in food availability. Migratory birds of prey may therefore be particularly vulnerable to climate change because: 1) most are long‐lived and have relatively low reproductive capacity, 2) many feed predominately on insectivorous passerines, and 3) several undertake annual migrations totaling tens of thousands of kilometers. Using multi‐decadal datasets for 14 raptor species observed at six sites across the Great Lakes region of North America, we detected phenological shifts in spring migration consistent with decadal climatic oscillations and global climate change. While the North Atlantic and El Niño Southern Oscillations exerted heterogeneous effects on the phenology of a few species, arrival dates more generally advanced by 1.18 days per decade, a pattern consistent with the effects of global climate change. After accounting for heterogeneity across observation sites, five of the 10 most abundant species advanced the bulk of their spring migration phenology. Contrary to expectations, we found that long‐distance migrants and birds with longer generation times tended to make the greatest advancements to their spring migration. Such results may indicate that phenotypic plasticity can facilitate climatic responses among these long‐lived predators. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-05T00:07:01.193797-05:
      DOI: 10.1111/jav.00692
       
  • Trans‐equatorial range of a land bird lineage (Aves: Rallidae) from
           tropical forests to subantarctic grasslands
    • Abstract: Despite the capacity for dispersal, range size varies considerably among birds species. Many species have restricted geographic spread, whilst others routinely travel long distances to reach preferred habitat. These alternatives are well expressed amongst the rails (Rallidae) and a varying tendency for movement results in overlapping distribution patterns. Here, we examine the situation of a particular lineage, the Lewinia rails (L. mirifica, L. pectoralis and L. muelleri) that inhabit a very wide spatial and ecological range. Lewinia occurs from the Philippines, north of the equator in Oceania, to Australia and the subantarctic Auckland Islands far to the south. Allopatric distribution and differences in plumage colour result in their treatment as distinct species but our molecular analysis reveals genetic distances of less than < 1%. The genetic and phylogeographical structure in the Lewinia lineage includes shared nuclear sequence alleles and this is consistent with a callibrated multigene phylogeny suggesting trans‐hemispheric dispersal since the middle Pleistocene. Despite this recent history, available morphometric data indicates that the subantarctic population has relatively small wings for its mass, and this implies adaptation away from flight. Lewinia provides a nice example of the way dispersal and adaptation intersect over short time frames to generate diversity. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-05T00:06:45.203644-05:
      DOI: 10.1111/jav.00804
       
  • Multi‐decadal trends in spring arrival of avian migrants to the
           central Arctic coast of Alaska: effects of environmental and ecological
           factors
    • Authors: Ward D. H; J. Helmericks, J. W. Hupp, L. McManus, M. Budde, D. C. Douglas, K. D. Tape
      Abstract: Warming in the Arctic has caused the transition from winter to summer to occur weeks earlier over the last half century, yet little is known about whether avian migrants have altered their timing of arrival on breeding areas to match this earlier seasonal transition. Over a 50‐year period, we examined trends in the timing of the first arrival for 16 avian migrant species at the terminus of their northward migration along the central Arctic coast of Alaska and compared these trends to factors potentially influencing migration phenology. Date of first arrival occurred an average of 0.12 d yr‐1 or 6 d (range = 3–10 d) earlier across all species and did not differ significantly among species between 1964 and 2013. Local climatic variables, particularly temperature, had a greater effect on a species first arrival date than did large‐scale climatic predictors. First arrival date was 1.03 d earlier for every 1°C annual change in temperature, but there was nearly a 2‐fold difference in the range of responses across species (0.69–1.33 d °C‐1), implying that some species did better than others at timing their arrival with changing temperature. There was weak support for an influence of foraging strategy, migration distance, and flight path on timing of first arrival. Our findings, like others from temperate latitudes, indicate that avian migrants are responsive to changing environmental conditions, though some species appear to be more adaptive than others. This article is protected by copyright. All rights reserved.
      PubDate: 2015-09-03T04:37:23.728383-05:
      DOI: 10.1111/jav.00774
       
  • A Test for Repertoire Matching in Eastern Song Sparrows
    • Authors: Adrienne L. DuBois; Stephen Nowicki, William A. Searcy
      Abstract: Repertoire matching occurs when one songbird replies to another with a song type that the two birds share. Repertoire matching has previously been demonstrated to occur at well above chance levels in a western population of song sparrows, where it is hypothesized to serve as a low level threat in a hierarchy of aggressive signals. Here we test for repertoire matching in an eastern population of song sparrows. Previous work indicates that this eastern population differs from the western one in having lower levels of song sharing between neighboring males and in showing no association between song sharing and territory tenure. Here we confirm that males in this eastern population on average share few whole songs with their neighbors. The eastern males are familiar with their neighbors’ repertoires, as evidenced by a stronger singing response to stranger song than to neighbor song. Males in the eastern population did not repertoire match: when played an unshared song type from a specific neighbor, they did not reply with a song type shared with that neighbor more often than expected by chance or more often than in response to playback of a control song (an unshared stranger song). The results thus demonstrate a qualitative difference in vocal signaling strategies between two populations of the same species. This article is protected by copyright. All rights reserved.
      PubDate: 2015-08-18T22:06:05.390341-05:
      DOI: 10.1111/jav.00811
       
  • Does nest predation risk affect the frequency of extra‐pair
           paternity in a socially monogamous passerine'
    • Authors: Teru Yuta; Itsuro Koizumi
      Abstract: While considerable variations in both the frequency of extra‐pair paternity (EPP) and the behavioral events that produce it are recognized among species, populations, individuals, and breeding attempts, the determinants of these variations are surprisingly difficult to establish. Nest predation may be one such determinant, since it is the most important source of reproductive failure, and past studies have suggested a variety of reproductive flexibilities under nest predation risk. However, despite its potentially significant effect on mating behaviors, nest predation risk has rarely been discussed in association with variations in intraspecific EPP patterns. Here, we examined the effect of naturally occurring nest predation, which varied between sites, years, and breeding attempts, on patterns of EPP in 92 broods (132 adults and 710 nestlings) of the Japanese great tit Parus major minor. We found that the frequency of extra‐pair offspring was positively correlated with the nest predation rate, along with a correlation to breeding attempts in a season, but not with other factors such as individual quality or breeding density. Under high nest‐predation risk, it may be adaptive for males to search for additional extra‐pair copulation to spread the risk of losing all offspring and to invest less in mate‐guarding, which also enables females to seek additional extra‐mating. The results of this study suggest that nest predation risk, among other factors, may significantly influence paternity allocation in birds. This article is protected by copyright. All rights reserved.
      PubDate: 2015-08-14T06:07:34.029219-05:
      DOI: 10.1111/jav.00713
       
  • Comparative demographics of a Hawaiian forest bird community
    • Authors: Alban Guillaumet; Bethany L. Woodworth, Richard J. Camp, Eben H. Paxton
      Abstract: Estimates of demographic parameters such as survival and reproductive success are critical for guiding management efforts focused on species of conservation concern. Unfortunately, reliable demographic parameters are difficult to obtain for any species, but especially for rare or endangered species. Here we derived estimates of adult survival and recruitment in a community of Hawaiian forest birds, including eight native species (of which three are endangered) and two introduced species at Hakalau Forest National Wildlife Refuge, Hawaiʻi. Integrated population models (IPM) were used to link mark‐recapture data (1994‐1999) with long‐term population surveys (1987‐2008). To our knowledge, this is the first time that IPM have been used to characterize demographic parameters of a whole avian community, and provides important insights into the life history strategies of the community. The demographic data were used to test two hypotheses: (i) arthropod specialists, such as the ‘Akiapōlā‘au (Hemignathus munroi), are 'slower' species characterized by a greater relative contribution of adult survival to population growth, i.e. lower fecundity and increased adult survival; and (ii) a species’ susceptibility to environmental change, as reflected by its conservation status, can be predicted by its life history traits. We found that all species were characterized by a similar population growth rate around one, independently of conservation status, origin (native vs. non‐native), feeding guild, or life history strategy (as measured by 'slowness'), which suggested that the community had reached an equilibrium. However, such stable dynamics were achieved differently across feeding guilds, as demonstrated by a significant increase of adult survival and a significant decrease of recruitment along a gradient of increased insectivory, in support of hypothesis (i). Supporting our second hypothesis, we found that slower species were more vulnerable species at the global scale than faster ones. The possible causes and conservation implications of these patterns are discussed. This article is protected by copyright. All rights reserved.
      PubDate: 2015-08-14T06:07:16.72257-05:0
      DOI: 10.1111/jav.00756
       
  • Chemical defence in avian brood parasites: production and function of
           repulsive secretions in common cuckoo chicks
    • Abstract: The use of active chemical defence against predators is relatively rare in birds. Among others, it has been reported for some members of family Cuculidae whose chicks, when threatened, expel dark foul‐smelling liquid from their cloaca. Apart from the brood parasitic great spotted cuckoo Clamator glandarius, however, this phenomenon has not yet been systematically studied in any other cuckoo species. Here we investigated the repellent behaviour in the evicting brood parasite, the common cuckoo Cuculus canorus, parasitizing the great reed warbler Acrocephalus arundinaceus. We explored whether production of secretions varies with chick age or size, and tested its presumed repellent function against various types of predators. We found that the production of secretions commenced at the age of approximately eight days, then gradually increased and decreased again shortly before fledging. Furthermore, we experimentally confirmed a more intensive repellent effect of the secretions on mammal predators than on avian predators, such as raptors and owls. The secretions have, however, no effect on corvid predators, probably because these scavengers often consume malodorous food. Further experimental studies together with phylogenetic comparative analyses are needed to elucidate the origin and function of this intriguing phenomenon both in parasitic and non‐parasitic cuckoos. This article is protected by copyright. All rights reserved.
      PubDate: 2015-08-14T06:06:55.628599-05:
      DOI: 10.1111/jav.00785
       
  • Incubation temperature influences survival in a small passerine bird
    • Authors: Henrik H. Berntsen; Claus Bech
      Abstract: In birds parental incubation behaviour is an important factor shaping the environmental conditions under which the embryos develop, and sub‐optimal incubation temperatures are known to negatively affect early growth and development. It is less well known if variation in incubation temperature can impose life‐long differences in individual performance and survival. In the present study we investigated the effects of incubation temperature on long‐term survival in a small passerine bird. Using our captive population of the zebra finch Taeniopygia guttata we artificially incubated eggs at three biologically relevant temperatures (35.9, 37.0 and 37.9 oC) for two‐thirds of the incubation period and then monitored individual lifespan of the hatched chicks for two and a half years. We found that individuals from eggs incubated under the lowest temperature exhibited significantly lower long‐term survival compared to those which had been incubated at the highest temperature. Our results show that incubation temperature in birds, and thus parental incubation behaviour, play an important role in shaping the life‐history trajectories of offspring. This article is protected by copyright. All rights reserved.
      PubDate: 2015-08-14T06:06:37.697525-05:
      DOI: 10.1111/jav.00688
       
  • Condition‐dependent expression of carotenoid‐ and
           melanin‐based plumage colour of northern flicker nestlings revealed
           by manipulation of brood size
    • Authors: Annessa B. Musgrove; Karen L. Wiebe
      Abstract: Carotenoid‐based colouration in feathers is widely accepted to be a reliable signal of the health of an individual, but the condition‐dependence of melanin‐based plumage ornaments has been highly debated. Using broods that were manipulated in size, we tested whether nutritional stress during rearing affected the carotenoid pigmentation in secondary feathers and the size, shape, and symmetry of melanin spots on breast plumage of northern flicker (Colaptes auratus) nestlings. Two measures of carotenoid colour (chroma and brightness) of secondary flight feathers did not vary according to brood size treatment, but in a larger dataset from the population, carotenoid chroma was positively associated with nestling mass. Nestlings from experimentally enlarged broods had smaller melanin spots than those from reduced broods, which is some of the first experimental evidence that melanin ornament size in growing nestlings is condition‐dependent. However, the shape and symmetry of the melanin breast spots was not associated with nestling mass. Sexual dimorphism was apparent in both types of pigmentation and future studies should investigate whether there are any trade‐offs for nestlings between investing in carotenoid colouration and melanisation and whether trade‐offs differ between the sexes. This article is protected by copyright. All rights reserved.
      PubDate: 2015-07-31T08:57:45.914275-05:
      DOI: 10.1111/jav.00730
       
  • The role of pigment based plumage traits in resolving conflicts
    • Authors: Catherine Mary Young; Kristal Elaine Cain, Nina Svedin, Patricia Ruth Yvonne Backwell, Sarah Rosalind Pryke
      Abstract: The role of melanin ‘badges of status’, in male‐male competition has been well‐studied, in contrast, carotenoid based plumage has largely been examined in the context of female mate choice. Recent work has shown that carotenoid signals can also function in male‐male competition, although the functions of the two types of signals is currently unclear. Here, we examine the relationships between colouration, dominance and aggression in the crimson finch (Neochmia phaeton), a species where males have both conspicuous red carotenoid plumage and a black melanin patch. We examined the importance of carotenoid and melanin based signals in three contexts: 1) among free‐living birds interacting at a feeding station: we found that neither colour signal influenced the outcome of interactions; 2) in staged dyadic contest in captivity: we found that coloration from carotenoid pigments was positively related to the probability of winning a contest, while the size of the melanin plumage patch was not related to winning; and 3) in staged dyadic contests where male plumage colour had been masked: we found that the number of interactions required to determine dominance increased. While the underlying natural plumage colour was still important in these contests, birds with more intense carotenoid colouration were now more likely to lose. These results confirm carotenoid‐based signalling in male‐male contests. However this signal is used in conjunction with other factors such as self‐assessment and body condition. Contrary to traditional expectations, the black melanin patch was not found to be important in this context. This article is protected by copyright. All rights reserved.
      PubDate: 2015-07-30T03:51:52.176948-05:
      DOI: 10.1111/jav.00742
       
  • WHY RENEW FRESH FEATHERS? ADVANTAGES AND CONDITIONS FOR THE EVOLUTION
           OF COMPLETE POST‐JUVENILE MOULT
    • Authors: Yosef Kiat; Ido Izhaki
      Abstract: Juveniles of several passerine species renew all of their fresh juvenile feathers immediately after fledging (complete post‐juvenile moult), in contrast to the majority, which perform a partial post‐juvenile moult. To understand the adaptive roles of this phenomenon we compared the quality of juvenile plumage in species that perform a complete post‐juvenile moult with that of species which perform a partial post‐juvenile moult; we similarly compared juveniles and adults in each of these groups. The quality of feathers was measured by mass of primaries, colour, and length. In species which perform a complete post‐juvenile moult the plumage quality of second‐year individuals, in their first breeding season, is similar to the plumage quality of adults, unlike those species that perform a partial post‐juvenile moult. In species which perform complete post‐juvenile moult, the quality of the feathers grown in the nest is lower than the quality of adult post‐breeding feathers. In contrast, in species which perform partial post‐juvenile moult the quality of the feathers grown in the nest is similar to that of adult post‐breeding feathers. We found that a complete post‐juvenile moult strategy is much more common (1) in residents and short‐distance migrants than in long‐distance migrants, (2) in southern latitudes, (3) in species with medium body mass and (4) in omnivores and granivores. Our results indicate two adaptive roles of the complete post‐juvenile moult strategy: (I) achieving high quality plumage in the first year which may increase individual survival probability and fitness and (II) allocating fewer resources to nestling plumage and more to nestling development, which enables the nestlings to leave the nest earlier, thus reducing the probability of encountering nest predators. We suggest that the complete post‐juvenile moult, immediately after fledging, is an optimal strategy in favourable habitats and under low time constraints, as in some tropical ecosystems. This article is protected by copyright. All rights reserved.
      PubDate: 2015-06-18T02:12:32.136712-05:
      DOI: 10.1111/jav.00717
       
  • Experimental manipulation of food availability leads to short‐term
           intra‐clutch adjustment in egg mass but not in yolk androgen or
           thyroid hormones
    • Authors: Suvi Ruuskanen; Veerle M. Darras, Bonnie de Vries, Marcel E. Visser, Ton G.G. Groothuis
      Abstract: In birds, mothers can affect their offspring's phenotype and thereby survival via egg composition. It is not well known to what extent and time‐scales environmental variation in resource availability, either via resource constrains or adaptive adjustment to predicted rearing conditions, influences maternal effects. We experimentally studied whether egg and yolk mass and yolk hormone levels respond to short‐term changes in food availability during laying in wild great tits (Parus major). Our treatment groups were: 1) food supplementation (mealworms) from the 1st until the last egg; 2) food supplementation from the 1st first until the 5th egg, where the effect of cessation of the supplementary food treatment could also be studied; 3) no food supplementation (controls). We analysed both nutritional resources (egg, yolk and albumen mass), and the important developmental signals, yolk androgens (testosterone and androstenedione), and for the first time in a wild population, yolk thyroid hormones (thyroxine and 3,5,3’‐triiodothyronine). Egg mass is a costly resource for females, androgens most likely non‐costly signals, whereas thyroid hormones may be costly signals, requiring environmental iodine. In the food supplemented group egg, yolk and albumen mass increased rapidly relative to controls and when food supplementation was halted, egg and albumen mass decreased, indicating rapid responses to resource availability. Yolk androgen and thyroid hormone levels were not affected by food supplementation during laying. Thyroxine showed an increase over the laying sequence and its biological meaning needs further study. The rapid changes in egg mass to variation in within‐clutch food availability suggest energetic/protein/nutrient constrains on egg formation. The lack of a response in yolk hormones suggest that perhaps in this species the short‐term changes in resource availability during egg laying do not predict offspring rearing conditions, or (for thyroid hormones) do not cause systemic changes in circulating hormones, and hence do not affect maternal signaling. This article is protected by copyright. All rights reserved.
      PubDate: 2015-06-18T02:11:15.789834-05:
      DOI: 10.1111/jav.00728
       
  • Cold tolerance, and not earlier arrival on breeding grounds, explains
           why males winter further north in an Arctic‐breeding songbird
    • Authors: Christie A. MacDonald; Emily A. McKinnon, H. Grant Gilchrist, Oliver P. Love
      Abstract: Sex biases in distributions of migratory birds during the non‐breeding season are widespread; however, the proximate mechanisms contributing to broad‐scale sex‐ratio variation are not well understood. We analyzed a long‐term winter‐banding dataset in combination with spring migration data from individuals tracked by using geolocators to test three hypotheses for observed variation in sex‐ratios in wintering flocks of Snow Buntings (Plectrophenax nivalis). We quantified relevant weather conditions in winter (temperature, snowfall and snow depth) at each banding site each year and measured body size and condition (fat scores) of individual birds (n >5500). We also directly measured spring migration distance for 17 individuals by using light‐level geolocators. If the distribution pattern of birds in winter is related to interactions between individual body size and thermoregulation, then larger bodied birds (males) should be found in colder sites (body size hypothesis). Males may also winter closer to breeding grounds to reduce migration distance for early arrival at breeding sites (arrival timing hypothesis). Finally, males may be socially dominant over females, and thus exclude females from high‐quality wintering sites (social dominance hypothesis). We found support for the body size hypothesis, in that colder and snowier weather predicted both larger body size and higher proportions of males banded. Direct tracking revealed that males did not winter significantly closer to their breeding site, despite being slightly further north on average than females from the same breeding population. We found some evidence for social dominance, in that females tended to carry more fat than males, potentially indicating lower habitat quality for females. Global climatic warming may reduce temperature constraints on females and smaller‐bodied males, resulting in broad‐scale changes in distributional patterns. Whether this has repercussions for individual fitness, and therefore population demography, is an important area of future research. This article is protected by copyright. All rights reserved.
      PubDate: 2015-06-10T10:44:53.663048-05:
      DOI: 10.1111/jav.00689
       
  • Genetic divergence of Troglodytes troglodytes islandicus from other
           subspecies of Eurasian Wren in Northwestern Europe
    • Abstract: The Icelandic subspecies of Eurasian Wren Troglodytes troglodytes islandicus has been described as a large wren which is sedentary on the island. It is one member of a large passerine complex which is widely distributed over the Holarctic except the Arctic. The taxonomic affiliation of the subspecies is mainly based on variation in plumage and on the song complexity. This study investigated the genetic differentiation of T. t. islandicus among the Eurasian Wren subspecies in Northwestern Europe, and especially in relation to its geographically proximate populations in the Faroe Islands, Scotland, Southern Norway, Sweden and Denmark. T. t. islandicus and the Faroese subspecies (T. t. borealis) were genetically differentiated from the other subspecies (T. t. indigenus and T. t. troglodytes) with an estimated time of divergence from this group during the last glacial maximum; 21 thousand years before present (KYBP) [44‐8]. A clear but a more recent split was observed between T. t. islandicus and T. t. borealis 12 KYBP [28‐4]. This article is protected by copyright. All rights reserved.
      PubDate: 2015-06-10T10:22:46.472332-05:
      DOI: 10.1111/jav.00744
       
  • Egg temperature and initial brood patch area determine hatching asynchrony
           in Magellanic Penguin Spheniscus magellanicus
    • Authors: Barrionuevo Melina; Esteban Frere
      Abstract: In birds, the adaptive significance of hatching asynchrony has been under debate for many years and the parental effects on hatching asynchrony have been largely assumed but not often tested. Some authors suggest that hatching asynchrony depends on the incubation onset and many factors have been shown to influence hatching asynchrony in different species. Our objective was to analyze the exact timing of the onset of incubation and if this affects hatching asynchrony; and, in addition, which other factors (brood patch development, incubation position, adult body condition, intra‐clutch egg dimorphism, laying date and year) affect hatching asynchrony in Magellanic Penguins (Spheniscus magellanicus). We first estimated the eggshell temperature at which embryo development starts, with a non‐destructive and novel method. We then recorded individual egg temperatures in 61 nests during incubation, and related them, and other breeding parameters, to hatching asynchrony. We also observed incubation positions in 307 nests. We found a significant positive relationship between hatching asynchrony and the temperature that the first‐laid egg experienced during egg laying and between hatching asynchrony and the initial brood patch area. We also found a negative relationship between hatching asynchrony and the difference in temperature between second and first‐laid eggs within a clutch, measured after the egg‐laying period was finished. We ruled out position of the eggs during incubation, adult body condition, egg volume, laying date, and study year as factors influencing hatching asynchrony. The egg temperature during laying and the difference in temperature between eggs of a clutch are determinants of hatching asynchrony in Magellanic Penguins. This article is protected by copyright. All rights reserved.
      PubDate: 2015-05-27T10:13:09.190683-05:
      DOI: 10.1111/jav.00662
       
  • Is the denser contour feather structure in pale grey than in pheomelanic
           brown tawny owls (Strix aluco) an adaptation to cold environments'
    • Authors: Katja Koskenpato; Kari Ahola, Teuvo Karstinen, Patrik Karell
      First page: 1
      Abstract: In colour polymorphic species morphs are considered to be adaptations to different environments, where they have evolved and are maintained because of their differential sensitivity to the environment. In cold environments the plumage insulation capacity is essential for survival and it has been proposed that plumage colour is associated with feather structure and thereby the insulation capacity of the plumage. We studied the structure of contour feathers in the colour polymorphic tawny owl (Strix aluco). A previous study of tawny owls in the same population has found strong selection against the brown morph in cold and snowy winters whereas this selection pressure is absent in mild winters. We predicted that grey morphs have a denser and more insulative plumage, enabling them to survive better in cold climate compared to brown ones. The insulative plumulaceous part of the dorsal contour feathers was larger and the fine structure of the plumulaceous part of the feather was denser in grey tawny owls than in brown ones. In the ventral contour feathers the plumulaceous part of the feather was denser in females than in males and in older birds without any differences between morphs. Our study suggests that insulative microscopical feather structures differ between colour morphs and we propose that feather structure may be a trait associated with morph‐specific survival in cold environments. This article is protected by copyright. All rights reserved.
      PubDate: 2015-07-14T08:16:00.294305-05:
      DOI: 10.1111/jav.00746
       
  • Elevating perceived predation risk modifies the relationship between
           parental effort and song complexity in the song sparrow (Melospiza
           melodia)
    • Authors: Melissa L. Grunst; John T. Rotenberry, Andrea S. Grunst
      First page: 57
      Abstract: Adult‐directed predation risk elevates costs of parental care, and may thus modify relationships between sexually selected ornaments and parental effort by accentuating the tradeoff between survival and parental investment. We assessed multiple hypotheses regarding the relationship between maternal effort, paternal effort, and the sexually selected trait of male song complexity in the song sparrow (Melospiza melodia). Further, we explored whether experimentally elevating perceived adult‐directed predation risk near nests affected these relationships. We quantified two dimensions of song complexity: song repertoire size and residual syllable number (the relative number of syllables for a given song repertoire size). Under elevated perceived predation risk, but not in the absence of the predator stimuli, females mated to males with higher residual syllable number displayed higher nestling provisioning rates and performed a higher proportion of nestling provisioning trips. In other words, elevating perceived predation risk induced a pattern of maternal investment consistent with differential allocation. In contrast, under elevated perceived predation risk, only, females performed a lesser proportion of provisioning trips when mated to males with large song repertoire sizes. Further, consistent with the good parent hypothesis, males with large song repertoire sizes displayed lower latencies to return to the nest, independent of the predator stimuli. Results suggest that residual syllable number may reflect some aspect of male genetic quality, such that females are more willing to maintain maternal effort while facing heightened predation risk. On the other hand, females may gain paternal benefits when mated to males with large song repertoires. Our study supports the hypothesis that increased costs of parental care associated with predation risk may induce relationships between sexually selected traits and parental behavior, which may increase the strength of sexual selection. Additionally, results suggest that different aspects of song complexity may fulfill non‐equivalent signaling roles. This article is protected by copyright. All rights reserved.
      PubDate: 2015-06-29T02:36:32.918097-05:
      DOI: 10.1111/jav.00758
       
  • Light‐level geolocators reveal migratory connectivity in European
           populations of pied flycatchers Ficedula hypoleuca
    • Authors: J. Ouwehand; M.P. Ahola, A.N.M.A. Ausems, E.S. Bridge, M. Burgess, S. Hahn, C. Hewson, R.H.G. Klaassen, T. Laaksonen, H.M. Lampe, W. Velmala, C. Both
      First page: 69
      Abstract: Understanding what drives or prevents long‐distance migrants to respond to environmental change requires basic knowledge about the wintering and breeding grounds, and the timing of movements between them. Both strong and weak migratory connectivity have been reported for Palearctic passerines wintering in Africa, but this remains unknown for most species. We investigated whether pied flycatchers Ficedula hypoleuca from different breeding populations also differ in wintering locations in West‐Africa. Light‐level geolocator data revealed that flycatchers from different breeding populations travelled to different wintering sites, despite similarity in routes during most of the autumn migration. We found support for strong migratory connectivity showing an unexpected pattern: individuals breeding in Fennoscandia (S‐Finland and S‐Norway) wintered further west compared to individuals breeding at more southern latitudes in the Netherlands and SW‐United Kingdom. The same pattern was found in ring recovery data from sub‐Saharan Africa of individuals with confirmed breeding origin. Furthermore, population‐specific migratory connectivity was associated with geographical variation in breeding and migration phenology: birds from populations which breed and migrate earlier wintered further east than birds from ‘late’ populations. There was no indication that wintering locations were affected by geolocation deployment, as we found high repeatability and consistency in δ13C and δ15N stable isotope ratios of winter grown feathers of individuals with and without a geolocator. We discuss the potential ecological factors causing such an unexpected pattern of migratory connectivity. We hypothesise that population differences in wintering longitudes of pied flycatchers result from geographical variation in breeding phenology and the timing of fuelling for spring migration at the wintering grounds. Future research should aim at describing how temporal dynamics in food availability across the wintering range affects migration, wintering distribution and populations’ capacity to respond to environmental changes. This article is protected by copyright. All rights reserved.
      PubDate: 2015-06-29T02:37:03.525598-05:
      DOI: 10.1111/jav.00721
       
  • Calibrating the molecular clock beyond cytochrome b: assessing the
           evolutionary rate of COI in birds
    • First page: 84
      Abstract: Estimating the age of species or their component lineages based on sequence data is crucial for many studies in avian evolutionary biology. Although calibrations of the molecular clock in birds have been performed almost exclusively using cytochrome b (cyt b), they are commonly extrapolated to other mitochondrial genes. The existence of a large, standardized cytochrome c oxidase subunit I (COI) library generated as a result of the DNA barcoding initiative provides the opportunity to obtain a calibration for this mitochondrial gene in birds. In this study we compare the evolutionary rate of COI relative to cyt b across ten different avian orders. We obtained divergence estimates for both genes from nearly 300 phylogenetically independent pairs of species through the analysis of almost 5000 public sequences. For each pair of species we calculated the difference in divergence between COI and cyt b. Our results indicate that COI evolves on average 14% slower than cyt b, but also reveal considerable variation both among and within avian orders, precluding the use of this value as a standard adjustment for the COI molecular clock for birds. Our findings suggest that this variation is partially explained by a clear negative relationship between the difference in divergence in these genes and the age of species. Distances for cyt b are higher than those for COI for closely related species, but the values become similar as the divergence between the species increases. This appears to be the result of a stronger pattern of negative time‐dependency in the rate of cyt b than in that of COI, a difference that could be related to lower functional constraints on a small number of sites in cyt b that allow it to initially accumulate mutations more rapidly than COI. This article is protected by copyright. All rights reserved.
      PubDate: 2015-06-29T02:36:47.477021-05:
      DOI: 10.1111/jav.00766
       
  • Recent speciation and elevated Z‐chromosome differentiation between
           sexually monochromatic and dichromatic species of Australian teals
    • Authors: Kirandeep K. Dhami; Leo Joseph, David A. Roshier, Jeffrey L. Peters
      First page: 92
      Abstract: Sex chromosomes potentially have an important role in speciation and often have elevated differentiation between closely related species. In birds, traits associated with male plumage, female mate preference, and hybrid fitness have been linked to the Z‐chromosome (females are heterogametic, ZW). We tested for elevated Z‐differentiation between two recently diverged species of Australian ducks, the sexually monochromatic grey teal (Anas gracilis) and the dichromatic chestnut teal (A. castanea). Despite prominent morphological differences, these two species are genetically indistinguishable at both mitochondrial DNA (mean ΦST < 0.0001) and 17 autosomal loci (mean ΦST = 0.0056). However, we detected elevated Z‐differentiation (mean ΦST = 0.271) and tentative evidence of an island of differentiation on the Z‐chromosome. This elevated differentiation was explained by a high frequency of derived alleles in chestnut teal that were absent in grey teal, which parallels independent evidence for a gain in dichromatism from a monochromatic ancestor. Coalescent estimates of demographic history and simulations indicated that the elevated Z‐differentiation was unlikely to be explained by neutral processes, but instead supported a role of divergent selection. We discuss evidence for models of speciation with gene flow versus adaptive divergence in the absence of gene flow and find that both hypotheses are plausible explanations of the data. Overall, these teal have the weakest background differentiation documented to date for a species showing a large Z‐effect, and they are an excellent model species for studying speciation genomics and the evolution of sexual dichromatism. This article is protected by copyright. All rights reserved.
      PubDate: 2015-07-27T04:18:43.073492-05:
      DOI: 10.1111/jav.00693
       
  • BEHAVIOURAL RESPONSES DURING FEATHER REPLACEMENT IN HOUSE SPARROWS
    • First page: 103
      Abstract: Birds lose feathers, whether during molt or by accident, and replace them by processes that are energetically demanding. We hypothesized that house sparrows, Passer domesticus biblicus, use behavioral means to save energy when feathers are lost, and tested the general prediction that house sparrows growing new feathers adjust their behavior to minimize the energy costs of foraging and to increase net energy gain from their food. To test these predictions we divided 18 house sparrows into three groups: 1) plucked – house sparrows from which we plucked 15 flight feathers; 2) cut – house sparrows in which the same 15 feathers were cut off at the calamus below the barbs; and 3) control ‐ unmanipulated house sparrows with plumage intact. We recorded both the quantity of seeds the house sparrows ate and the time they spent foraging from assay food patches. We found that "plucked" sparrows growing new feathers adjust their foraging behavior by reducing their feeding time and the number of visits to a food patch. This allowed them to increase their patch harvest rate while maintaining a steady body mass. This article is protected by copyright. All rights reserved.
      PubDate: 2015-07-30T03:52:23.970214-05:
      DOI: 10.1111/jav.00651
       
  • Icterus spurius and I. fuertesi
    • Authors: Rachel J. Sturge; Kevin E. Omland, J. Jordan Price, Bernard Lohr
      First page: 109
      Abstract: Birdsong has important functions in attracting and competing for mates, and song characteristics are thought to diverge rapidly during the process of speciation. In contrast, other avian vocalizations that may have non‐reproductive functions, such as calls, are thought to be more evolutionarily conserved and may diverge more slowly among taxa. This study examines differences in both male song and an acoustically simpler vocalization, the ‘jeet’ call, between two closely related taxa, Icterus spurius and I. fuertesi. A previous study comparing song syllable type sharing within and between I spurius and I. fuertesi indicated that their songs do not differ discernibly. Here we measured 18 acoustic characteristics of their songs and found strong evidence supporting this prior finding. In contrast, we measured 17 acoustic characteristics of jeet calls and found evidence of significant divergence between the two taxa in many of these characteristics. Calls in I. fuertesi have a longer duration, a larger frequency bandwidth, a lower minimum frequency, a lower beginning frequency, and greater levels of both frequency and amplitude modulation in comparison to the calls of I. spurius. In addition, I. fuertesi calls contain two distinct parts, while the calls of I. spurius have only one part. Thus, we find evidence of divergence in the calls of the two taxa but not their songs challenging the widespread assumption that complex bird song evolves more rapidly than other types of vocalizations. Understanding divergence in multiple vocalization types as well as other behavioral, morphological, and molecular traits is important to understanding the earliest stages of speciation. This article is protected by copyright. All rights reserved.
      PubDate: 2015-07-27T04:16:20.611247-05:
      DOI: 10.1111/jav.00595
       
  • Sons do not take advantage of a head start: Parity in herring gull
           offspring sex ratios despite greater initial investment in males
    • Authors: David N. Bonter; Michelle C. Moglia, Luke E. DeFisher
      First page: 121
      Abstract: Skewed adult sex ratios sometimes occur in populations of free‐living animals yet the proximate mechanisms, timing of sex‐biases, and the selective agents contributing to skew remain a source of debate with contradictory evidence from different systems. We investigated potential mechanisms contributing to sex biases in a population of herring gulls with an apparent female skew in the adult population. Theory predicts that skewed adult sex ratios will adaptively lead to skewed offspring sex ratios to restore balance in the effective breeding population (Fisher 1958). Parents may also adaptively bias offspring sex ratios to increase their own fitness in response to environmental factors (Trivers and Willard 1973). Therefore, we expected to detect skewed sex ratios either at hatching or at fledging as parents invest differentially in offspring of different sexes. We sampled complete clutches (N = 336 chicks) at hatching to quantify potential skews in sex ratios by position in the hatch order, time of season, year, and nesting context (nest density), finding no departure from equal sex ratios at hatching related to any of these factors. Further, we sampled 258 chicks at near‐fledging to investigate potential sex biases in survival at the chick stage. Again, no biases in sex ratios were recorded. Male offspring were favored in this population via greater maternal investment in eggs carrying male embryos and greater parental provisioning of male offspring which reached greater sizes by fledging. Despite the advantages realized by male offspring, females were equally as likely to fledge as males. Thus, biased adult sex ratios apparently arise in the post‐fledging and pre‐recruitment stage in our population. This article is protected by copyright. All rights reserved.
      PubDate: 2015-07-27T04:17:35.45598-05:0
      DOI: 10.1111/jav.00649
       
  • Immense plasticity of timing of breeding in a sedentary forest passerine,
           Poecile palustris
    • First page: 129
      Abstract: Numerous bird species have advanced their breeding seasons in response to climate warming. These changes were mostly brought about by phenotypic plasticity, i.e. flexible reactions of individual birds, rather than by microevolutionary change. Knowing the limits of plasticity is thus of paramount importance in any attempt to predict possible reactions of birds to climate warming. However, the breeding performance of the same individuals in contrasting environmental conditions, necessary to answer this question, is rarely observed. Here, we provide data on the flexibility in timing of egg‐laying of individual Marsh Tit Poecile palustris females breeding in an extremely late (2013) and early (2014) spring in Białowieża National Park (Poland). In both years the birds stayed in the same places in the primeval old‐growth forest, free of direct human influences (no nest‐boxes, no additional food). The weather variation was within the range of conditions observed during 40 years in the study area, and no climate warming occurred in the Marsh Tit's pre‐breeding period. Females (n = 16) shifted the onset of laying by 13‐23 (median = 20) days between the seasons. This range of individual flexibility encompasses almost the whole latitudinal range of the breeding dates found across Europe. Such a buffer of plasticity would probably be sufficient for Marsh Tits to adjust the onset of egg‐laying to the forecasted range of climate change. A combination of temperature and photoperiod appears to be involved in fine tuning of the birds’ breeding times with spring conditions, but how the birds asses and integrate this information remains poorly understood. This article is protected by copyright. All rights reserved.
      PubDate: 2015-07-01T02:26:37.34386-05:0
      DOI: 10.1111/jav.00733
       
  • Investigating how telomere dynamics, growth and life history covary along
           an elevation gradient in two passerine species
    • First page: 134
      Abstract: Telomeres are specialized non‐coding DNA sequences that cap the end of chromosomes and protect genome integrity. Because telomeres shorten during development and their length at maturity is often associated with survival, one hypothesis is that telomere erosion during early growth is closely associated with life history trajectories of individuals and species. Elevation gradients lead to systematic changes in environmental factors, and thus they provide unique opportunities to explore how life history trajectories and telomere dynamics can covary under various environmental conditions. Here, we address this question in chicks of two tit species distributed foremost at low elevation (the great tit, Parus major) or at high elevation (the coal tit, Periparus ater). With increasing elevation, great tits showed delayed breeding, and their chicks a slower development, higher telomere erosion and shorter telomere length at day 16. Although coal tit parents delayed also their breeding with increasing elevation, their chicks had a faster development, higher telomere erosion but no reduced telomere length at day 16. This last result is explained by coal tit chicks having longer telomeres at day 7 at high than low elevation, thus mitigating effects of fast telomere erosion before fledging. Our findings on life histories support the idea that great tits and coal tits are best adapted to low and high elevation, respectively. Our data on telomere provide however no support for a direct link between early growth rate and telomere dynamics, but underline complex interplays between telomere dynamics and environmental conditions experienced early in life, thereby urging for studies identifying how early life conditions actually determine fledgling's telomere length. This article is protected by copyright. All rights reserved.
      PubDate: 2015-07-01T02:26:20.812894-05:
      DOI: 10.1111/jav.00714
       
 
 
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