for Journals by Title or ISSN
for Articles by Keywords
  Subjects -> BIOLOGY (Total: 2858 journals)
    - BIOCHEMISTRY (213 journals)
    - BIOENGINEERING (95 journals)
    - BIOLOGY (1385 journals)
    - BIOPHYSICS (44 journals)
    - BIOTECHNOLOGY (187 journals)
    - BOTANY (219 journals)
    - CYTOLOGY AND HISTOLOGY (26 journals)
    - ENTOMOLOGY (59 journals)
    - GENETICS (150 journals)
    - MICROBIOLOGY (241 journals)
    - MICROSCOPY (11 journals)
    - ORNITHOLOGY (27 journals)
    - PHYSIOLOGY (65 journals)
    - ZOOLOGY (136 journals)

BIOLOGY (1385 journals)            First | 3 4 5 6 7 8 9 10 | Last

Integrative and Comparative Biology     Hybrid Journal   (Followers: 7)
Integrative Biology     Full-text available via subscription   (Followers: 4)
Interaction Studies     Hybrid Journal   (Followers: 9)
Interciencia     Open Access  
Interface Focus     Full-text available via subscription  
International Agrophysics     Open Access   (Followers: 1)
International Aquatic Research     Open Access   (Followers: 3)
International Biodeterioration & Biodegradation     Hybrid Journal   (Followers: 1)
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 Applied Sciences and Biotechnology     Open Access   (Followers: 2)
International Journal of Aquatic Biology     Open Access   (Followers: 11)
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 Biodiversity     Open Access   (Followers: 3)
International Journal of Biological and Chemical Sciences     Open Access   (Followers: 3)
International Journal of Biological Macromolecules     Hybrid Journal  
International Journal of Biological Sciences     Open Access   (Followers: 7)
International Journal of Biology     Open Access   (Followers: 3)
International Journal of Biomaterials     Open Access   (Followers: 5)
International Journal of Biomathematics     Hybrid Journal  
International Journal of Biomedical Engineering and Technology     Hybrid Journal   (Followers: 5)
International Journal of Biomedical Nanoscience and Nanotechnology     Hybrid Journal   (Followers: 6)
International Journal of Biometrics     Hybrid Journal   (Followers: 4)
International Journal of Brain Science     Open Access   (Followers: 1)
International Journal of Cell Biology     Open Access   (Followers: 6)
International Journal of Chemical and Life Sciences     Open Access   (Followers: 3)
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: 5)
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 High Throughput Screening     Open Access   (Followers: 2)
International Journal of Impact Engineering     Hybrid Journal   (Followers: 8)
International Journal of Innovation and Applied Studies     Open Access   (Followers: 4)
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 Science and Medical Research     Open Access   (Followers: 4)
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: 5)
International Journal of Natural Sciences     Open Access   (Followers: 1)
International Journal of Peptide Research and Therapeutics     Partially Free   (Followers: 5)
International Journal of Peptides     Open Access   (Followers: 5)
International Journal of Pharmaceutical and Life Sciences     Open Access   (Followers: 5)
International Journal of Phytoremediation     Hybrid Journal   (Followers: 2)
International Journal of Plant Genomics     Open Access   (Followers: 2)
International Journal of Plant Research     Open Access   (Followers: 3)
International Journal of Primatology     Hybrid Journal   (Followers: 5)
International Journal of Proteomics     Open Access   (Followers: 1)
International Journal of Secondary Metabolite     Open Access   (Followers: 1)
International Journal of Signs and Semiotic Systems     Full-text available via subscription  
International Journal of Speleology     Open Access   (Followers: 9)
International Journal of Systems Biology and Biomedical Technologies     Full-text available via subscription   (Followers: 2)
International Journal of Tropical Insect Science     Hybrid Journal   (Followers: 1)
International Journal of Tryptophan Research     Open Access   (Followers: 1)
International Review of Cell and Molecular Biology     Full-text available via subscription   (Followers: 6)
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: 2)
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: 3)
Izvestiya, Physics of the Solid Earth     Hybrid Journal   (Followers: 3)
Japanese Journal of Applied Physics     Full-text available via subscription   (Followers: 3)
JCP : BioChemical Physics     Hybrid Journal   (Followers: 2)
JETP Letters     Hybrid Journal   (Followers: 3)
Journal of Bacteriology & Parasitology     Open Access   (Followers: 3)
Journal of Bioanalysis & Biomedicine     Open Access   (Followers: 1)
Journal of Bioequivalence & Bioavailability     Open Access  
Journal of Bioremediation & Biodegradation     Open Access   (Followers: 2)
Journal of Computer Science & Systems Biology     Open Access   (Followers: 2)
Journal of Proteomics & Bioinformatics     Open Access   (Followers: 7)
Journal of Advance Researches In Biological Sciences     Open Access   (Followers: 3)
Journal of Advances in Biology     Open Access   (Followers: 3)
Journal of Agricultural, Biological & Environmental Statistics     Hybrid Journal   (Followers: 9)
Journal of Amino Acids     Open Access   (Followers: 3)
Journal of AOAC International     Full-text available via subscription   (Followers: 8)
Journal of Applied Biobehavioral Research     Hybrid Journal  
Journal of Applied Bioinformatics & Computational Biology     Hybrid Journal   (Followers: 1)
Journal of Applied Biosciences     Open Access  
Journal of Applied Ichthyology     Hybrid Journal   (Followers: 6)

  First | 3 4 5 6 7 8 9 10 | Last

Journal Cover   Journal of Avian Biology
  [SJR: 1.201]   [H-I: 52]   [19 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0908-8857 - ISSN (Online) 1600-048X
   Published by John Wiley and Sons Homepage  [1597 journals]
  • Nesting success of native and introduced forest birds on the island of
    • 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:
    • 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
    • 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
    • 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
  • 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
  • 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
      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
  • 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
      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
  • Icterus spurius and I. fuertesi
    • Authors: Rachel J. Sturge; Kevin E. Omland, J. Jordan Price, Bernard Lohr
      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
  • 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
      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
  • Immense plasticity of timing of breeding in a sedentary forest passerine,
           Poecile palustris
    • 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
    • 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
  • 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
      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
    • 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
  • Elevating perceived predation risk modifies the relationship between
           parental effort and song complexity in the song sparrow (Melospiza
    • Authors: Melissa L. Grunst; John T. Rotenberry, Andrea S. Grunst
      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
    • 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
  • Fine‐scale habitat use during the non‐breeding season suggests
           that winter habitat does not limit breeding populations of a declining
           long‐distance Palearctic migrant
    • Authors: Emma Blackburn; Will Cresswell
      Abstract: For migrant birds, what habitats are suitable during the non‐breeding season influences habitat availability, population resilience to habitat loss, and ultimately survival. Consequently, habitat preferences during winter and whether habitat segregation according to age and sex occurs directly influences migration ecology, survival and breeding success. We tested the fine‐scale habitat preferences of a declining Palearctic migrant, the Whinchat Saxicola rubetra, on its wintering grounds in West Africa. We explored the influence of habitat at the territory‐scale and whether dominance‐based habitat occupancy occurs by describing the variation in habitat characteristics across wintering territories, the degree of habitat change within territories held throughout winter, and whether habitat characteristics influenced territory size and space‐use within territories or differed with age and sex. Habitat characteristics varied substantially across territories and birds maintained the same territories even though habitat changed significantly throughout winter. We found no evidence of dominance‐based habitat occupancy; instead, territories were smaller if they contained more perching shrubs or maize crops, and areas with more perching shrubs were used more often within territories, likely because perches are important for foraging and territory defence. Our findings suggest that Whinchats have non‐specialised habitat requirements within their wintering habitat of open savannah and farmland, and respond to habitat variation by adjusting territory size and space‐use within territories instead of competing with conspecifics. Whinchats show a tolerance for human‐modified habitats and results support previous findings that some crop types may provide high‐quality wintering habitat by increasing perch density and foraging opportunities. By having non‐specialised requirements within broad winter habitat types, migrants are likely to be flexible to changing wintering conditions in Africa, both within and across winters, so possibly engendering some resilience to the rapid anthropogenic habitat degradation occurring throughout their wintering range. This article is protected by copyright. All rights reserved.
      PubDate: 2015-05-27T10:13:54.448465-05:
      DOI: 10.1111/jav.00738
  • Space‐time tradeoffs in the development of precipitation‐based
           isoscape models for determining migratory origin
    • Authors: Hannah B. Zanden; Michael B. Wunder, Keith A. Hobson, Steven L. Wilgenburg, Leonard I. Wassenaar, Jeffrey M. Welker, Gabriel J. Bowen
      Abstract: Precipitation stable isotope patterns over continental scales provide a fundamental tool for tracking origins of migratory species. Hydrogen isotopes from rain and environmental waters are assimilated into animal tissues and may thereby reveal the location where tissues were synthesized. Predictive isotopic maps (or isoscapes) of stable hydrogen isotope values in precipitation (δ2Hp) are typically generated by time‐averaging observations from a global network of stations that have been sampled irregularly in space and time. We previously demonstrated that restricting the temporal range in δ2Hp isoscapes to biologically relevant time frames did not improve predictions of geographic origin for two migratory species in North America and Europe; rather, it decreased the accuracy of assignment. Here, we examined whether the reduction in assignment accuracy stemmed from a decrease in the number of sampling stations available to support isoscape development for shorter time periods. Multiple regression models were used to predict the hydrogen isotope composition in precipitation using isotopic measurements from each station along with a suite of independent variables. The reduction in the number of stations with δ2Hp measurements used to estimate isoscape model parameters did not alter the accuracy and precision of assignments consistently. We also examined accuracy across a range of reduced station numbers and found that mean accuracy was affected only at very low numbers of stations, indicating that the spatial isotopic patterns in precipitation that are useful for assignment applications can be characterized with data from relatively limited data stations. The number and spatial distribution of stations may have more influence when geostatistical models are used to generate isoscapes, as they incorporate spatial correlation in the dataset. The results can be used to guide future research in understanding how data availability and constraints in creating δ2Hp isoscapes may affect predictions of geographic origins. This article is protected by copyright. All rights reserved.
      PubDate: 2015-05-27T10:13:21.187725-05:
      DOI: 10.1111/jav.00656
  • 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
  • Faster spring migration in northern wheatears is not explained by an
           endogenous seasonal difference in refueling rates
    • Authors: Cas Eikenaar; Arseny Tsvey, Heiko Schmaljohann
      Abstract: A widespread phenomenon in migrant birds is that they travel faster in spring than in autumn. During migration birds spend most time at stopover sites and, correspondingly, the faster spring migration is mainly explained by shorter stopovers in spring than autumn. Because a main purpose of stopovers is to replenish the fuel used in flight, a higher rate of fuel deposition (FDR) in spring is thought to explain the shorter stopovers and hence shorter total duration of migration in spring. Critical migratory processes, including the onset and extent of pre‐migratory fueling, are endogenously regulated. It is therefore not unlikely that refueling at stopover sites is, at least partly, also under endogenous control. We here tested whether there is an endogenous seasonal difference in food intake and FDR, which could contribute to shorter stopovers and hence faster migration in spring. We measured daily food intake and daily FDR in two subspecies of the northern wheatear (Oenanthe oenanthe), temporarily confined at stopover under identical constant indoor conditions in spring and autumn. The two wheatear subspecies differed markedly in absolute food intake and FDR. Within subspecies, however, food intake and FDR did not differ between spring and autumn, indicating that faster spring migration in northern wheatears is not explained by an endogenously controlled seasonal difference in birds’ motivation to refuel. To further substantiate this claim, similar measurements should be taken at other locations along northern wheatears’ migration routes. Comparable experiments in other species could test the generality of our results. This article is protected by copyright. All rights reserved.
      PubDate: 2015-05-27T10:12:53.870344-05:
      DOI: 10.1111/jav.00734
  • Synchronization of laying by great spotted cuckoos and recognition ability
           of magpies
    • Abstract: Brood parasites rely entirely on the parental care of host species to raise the parasitic nestlings until independence. The reproductive success of avian brood parasites depends on finding host nests at a suitable stage (i.e. during egg laying) for parasitism and weakly defensive (i.e. non‐ejector) hosts. Finding appropriate nests for parasitism may, however, vary depending on ecological conditions, including parasite abundance in the area, which also varies from one year to another and therefore may influence coevolutionary relationships between brood parasites and their hosts. In this scenario, we explored: (i) the degree of laying synchronization between great spotted cuckoos (Clamator glandarius) and magpies (Pica pica) during two breeding seasons, which varied in the level of selection pressure due to brood parasitism (i.e. parasitism rate); (ii) magpie responses to natural parasitism in the pre‐laying period and successfulness of parasitic eggs laid at this stage; and (iii) magpie responses to experimental parasitism performed at different breeding stages. We found that, during the year of higher parasitism rate, there was an increase in the percentage of parasitic eggs laid before magpies started laying. However, the synchronization of laying was poor both years regardless of the differences in the parasitism rate. The ejection rate was significantly higher during the pre‐egg‐laying and the post‐hatching stages than during the laying stage, and hatching success of parasitic eggs laid during the pre‐egg‐laying stage was zero. Thus, non‐synchronized parasitic eggs are wasted and therefore poor synchronization should be penalized by natural selection. We discuss four different hypotheses explaining poor synchronization. This article is protected by copyright. All rights reserved.
      PubDate: 2015-05-13T07:08:07.676253-05:
      DOI: 10.1111/jav.00627
  • Common loon parents defend chicks according to both value and
    • Authors: Walter Piper; Gabriella Jukkala
      Abstract: In many territorial breeders, conspecifics that intrude during the chick‐rearing period pose a threat to survival of young. Defense of young from intruders is costly to parents, so it is likely that intense selective pressure has shaped chick defense so as to maximize parental fitness. We simulated territorial intrusion by exposing adult common loons (Gavia immer) and their chicks to a decoy and used mixed models to investigate responses. We tested two hypotheses: 1) the value hypothesis, which holds that parents should defend large broods of offspring more strongly because of the greater potential fitness benefits they offer, and 2) the vulnerability hypothesis, which predicts vigorous defense of young offspring, whose small size and limited mobility render them vulnerable to sudden attacks from intruders that approach under water. Under natural conditions, parents spent over 80% of their time within 20 meters of chicks younger than two weeks (“young chicks”) but 66% or less of their time close to chicks four weeks or older (“old chicks”). Parents of young chicks associated less with the decoy but yodelled and penguin danced more during decoy trials than did parents of old chicks, supporting the conclusion that the parents protected young chicks not by engaging intruders directly but by remaining close to chicks and using vocalization and display to keep intruders at a distance. While these findings lent clear support to the vulnerability hypothesis, the value hypothesis too was supported, as males with two‐chick broods were almost three times more likely to yodel than males with singleton chicks. Age of parents was not associated with any aspect of chick defense, but the paucity of known‐aged parents in the oldest age classes makes future investigation of age effects warranted. This article is protected by copyright. All rights reserved.
      PubDate: 2015-05-08T23:41:00.818374-05:
      DOI: 10.1111/jav.00648
  • An evaluation of different methods for assessing eggshell pigmentation and
           pigment concentration using great tit eggs
    • Abstract: The striking variation in colour and maculation of bird eggs has fascinated biologists since centuries, and many hypotheses based on mechanical, physiological or signalling functions have been proposed for its evolution by natural and sexual selection. Protoporphyrin is the main eggshell pigment found in brown maculated eggs, and is assumed to function as a mediator of these selection processes. It is a precursor of heme with pro‐oxidant properties, and hence a link between brown maculation and female condition has been proposed and tested in a number of studies, albeit with contrasting results. A variety of different visual methods have been used to quantify outer eggshell pigmentation, which has been assumed to correspond to overall quantity of protoporphyrin in the shell. Yet, this relationship has rarely been tested. The aim of this study was to apply four commonly used methods to assess pigmentation in great tit eggs with protoporphyrin as the predominant eggshell pigment, and to compare the results of these methods. Specifically, we i) ranked eggshell pigmentation by human naked eye, ii) applied a granularity approach and iii) measured spectrophotometric reflectance of eggshell pigments. Second, we estimated the relationship between outer eggshell pigmentation (i.e. estimated by three different methods above) and true protoporphyrin concentration deposited in the entire shell measured by HPLC. Among‐method estimates were significantly correlated for the traits describing pigment ‘darkness’ only. While the model including scores based on human naked eyes explained 16 % of the variance of pigment concentration in the entire shell, spectrometry explained 27 %, and the granularity approach explained 40 %. Thus, the estimation of true pigment concentration in the entire shell from the visible outer side of the shell is most reliable with the granularity approach. It is relevant for studies where the maintenance of the integrity of the eggs is essential. This article is protected by copyright. All rights reserved.
      PubDate: 2015-05-08T23:40:50.967917-05:
      DOI: 10.1111/jav.00495
  • Revealing unexpected uses of space by wintering Aquila pomarina: how does
           satellite telemetry identify behaviour at different scales'
    • Abstract: Little is understood about the dispersion and movements of Palaearctic migrant raptors while wintering in southern Africa. The high temporal and spatial resolution of GPS telemetry data provided the opportunity to describe how space is used by one such migratory raptor in its wintering range, the lesser spotted eagle Aquila pomarina. Kernel density estimation was used to map the distribution of three individuals at various spatial scales. In addition to their extremely large overall wintering range (up to 112 000 km2), three finer levels of spatial concentration were identified: favoured activity zones where the birds spent much of the winter, smaller core areas to which the birds returned each year, and tiny intensive foraging clusters. Philopatry was demonstrated by one bird which revisited core areas over eight wintering seasons. The same core areas, particularly the Waterberg, Grootfontein (Namibia) and the eastern and western sides of the Okavango Delta (Botswana), were visited by two other eagles in 2012/2013, although not simultaneously. Such results potentially provide important information on areas where conservation activities might be focused to mitigate human degradation of habitat. This article is protected by copyright. All rights reserved.
      PubDate: 2015-05-08T23:40:38.21829-05:0
      DOI: 10.1111/jav.00670
  • Novel insights into relationships between egg corticosterone and timing of
           breeding revealed by LC‐MS/MS
    • Abstract: Inter‐ and intra‐clutch variation in egg corticosterone (CORT), the major glucocorticoid in birds, may provide insights into how maternal stress levels vary with the timing of breeding and with laying order. Common analytical methods (e.g. immunoassays), however, suffer from cross‐reaction with other steroids, leading to potential overestimation of CORT concentrations which can obscure true hormone‐environment relationships and complicate among‐study comparisons. We here apply a new LC‐MS/MS technique, which has recently been shown to avoid the problem of cross‐reactivity due to its high specificity, to quantify CORT concentrations in yolk and albumen in clutches of lesser black‐backed gulls (Larus fuscus). We found that CORT concentration exhibited a previously unreported U‐shaped relationship with time of breeding, which we explain as a potential interplay of two forces, exerting extra strain on the early and late breeders. Furthermore, results showed an increase in CORT with laying order indicating the energetic expense of egg production. The levels of CORT assessed in this study were significantly lower than those previously reported in studies using immunoassays for CORT analysis. This supports the fact that incorporating chromatography effectively reduces overestimation of CORT due to cross‐reactivity with other steroid hormones, particularly in egg yolk. This article is protected by copyright. All rights reserved.
      PubDate: 2015-04-17T03:40:35.526558-05:
      DOI: 10.1111/jav.00735
  • The effect of kleptoparasite and host numbers on the risk of
           food‐stealing in an avian assemblage
    • Abstract: Kleptoparasitism involves the theft of resources such as food items from one individual by another. Such food‐stealing behaviour can have important consequences for birds, in terms of individual fitness and population sizes. In order to understand avian host‐kleptoparasite interactions, studies are needed which identify the factors which modulate the risk of kleptoparasitism. In temperate European intertidal areas, Eurasian oystercatchers (Haematopus ostralegus) feed primarily on bivalve molluscs, which may be stolen by kleptoparasitic species such as carrion crows (Corvus corone) and herring gulls (Larus argentatus). In this study we combined overwinter foraging observations of oystercatchers and their kleptoparasites on the Exe Estuary, UK, with statistical modelling to identify the factors that influence the likelihood of successful food stealing behaviour occurring. Across the winter, 16.4 % of oystercatcher foraging attempts ended in successful kleptoparasitism; the risk of theft was lowest in February (10.8 %) and highest in December (36.3 %). Using an information theoretic approach to compare multiple logistic regression models we present evidence that the outcome of host foraging attempts varied with the number of kleptoparasites per host within the foraging patch for two out of five individual months, and for all months grouped. Successful, kleptoparasitism was more likely to occur when the total number of all kleptoparasites per host was greater. Across the entire winter study period, oystercatcher foraging attempts that resulted in kleptoparasitism were associated with a mean number of kleptoparasites per host that was more than double that for foraging attempts that ended in the oystercatcher successfully consuming the mussel. Conversely, the stage of the tidal cycle within the estuary did not affect the outcome of oystercatcher foraging attempts. Our study provides evidence that bird numbers influence the risk of kleptoparasitism within avian assemblages. This article is protected by copyright. All rights reserved.
      PubDate: 2015-04-17T03:40:24.907426-05:
      DOI: 10.1111/jav.00705
  • Individual migration patterns of Eurasian golden plovers Pluvialis
           apricaria breeding in Swedish Lapland; examples of cold
           spell‐induced winter movements
    • Abstract: Tracking studies normally focus on long‐distance migrants, meaning that our understanding about short‐distance migration remains limited. In this study, we present the first individual tracks of the Eurasian golden plover Pluvialis apricaria, a short‐distance migrant, which were tracked from a Scandinavian breeding population using geolocators. In addition, golden plovers are known for their cold spell‐induced winter movements, and this study provides some first individual tracking data on this type of movements. In three cases the plovers spent the winter in NW Europe and in four cases they departed during winter from NW Europe to spend the rest of the winter in Iberia or Morocco (one bird that was tracked during two subsequent migration cycles moved to Iberia in the first winter but remained in NW Europe during the second winter). The four winter departures were associated with a cold spell in NW Europe during which maximum temperatures dropped to freezing. Cold spell‐induced winter movements were notably long and fast. The birds that remained at their NW European wintering site did not experience such cold spell. Interestingly, the individual that was tracked for a second season did experience four cold spells at its wintering site in NW France, but it never left this area, indicating that plovers not always move on in response to cold. Little information was obtained about spring migration, but one bird had a prominent counter‐clockwise loop migration pattern through E Europe. Due to their cold spell winter movements, golden plovers exhibit great flexibility in migration patterns, resulting in a notably large spread in final wintering areas. This article is protected by copyright. All rights reserved.
      PubDate: 2015-04-17T03:39:41.384834-05:
      DOI: 10.1111/jav.00768
  • Impacts of nest predators and weather on reproductive success and
           population limitation in a long‐distance migratory songbird
    • Authors: Thomas W. Sherry; Scott Wilson, Sarah Hunter, Richard T. Holmes
      Abstract: Although avian nesting success is much studied, little is known about the relative importance of the factors that contribute to annual reproductive success and population limitation, especially for long‐distance migratory songbird species. We combined a field experiment limiting access to nests by mammalian predators with modeling of long‐term field data of American redstarts (Parulidae: Setophaga ruticilla) to assess the effects of multiple environmental variables on breeding success and population limitation. Experimental treatment (baffles placed around tree boles beneath active nests; N = 71) increased nesting success of this single‐brooded species significantly (77% vs. 50% in controls; N = 343), demonstrating that scansorial mammals, primarily red squirrels (Tamiasciurus hudsonicus) and Eastern chipmunks (Tamias striatus), reduced reproductive success. Based on unbaffled nests (N = 466), daily nest survival varied annually, and was positively influenced by May temperature and negatively by sciurid nest predator abundance. Daily nest survival was also influenced positively by June rainfall, and declined with nest age but not with calendar date. Since nest failure was overwhelmingly caused by nest predation, these significant climate and nest‐age effects in our models are indirect, likely influencing nest predator and/or nesting bird behaviors that in turn influenced nest predation. Redstart population density had no effect on nesting success, after accounting for other factors. Annual reproductive success accounted for 34% of the variability in annual population change in redstarts in our study area. Our findings document 1) breeding season population limitation in this species, 2) a link between tree masting and bird population dynamics via mammal population fluctuations, 3) the independent contributions of summer versus winter population processes in a migratory species, and 4) the potential complexity of climate‐biotic interactions. This article is protected by copyright. All rights reserved.
      PubDate: 2015-04-16T03:22:58.453242-05:
      DOI: 10.1111/jav.00536
  • Does fragmentation of wetlands affect gene flow in sympatric Acrocephalus
           warblers with different migration strategies?
    • Abstract: Wetlands are naturally patchy habitats, but patchiness has been accentuated by the extensive wetlands loss due to human activities. In such a fragmented habitat, dispersal ability is especially important to maintain gene flow between populations. Here we studied population structure, genetic diversity and demographic history of Iberian and North African populations of two wetland passerines, the Eurasian reed warbler Acrocephalus scirpaceus and the moustached warbler Acrocephalus melanopogon. These species are closely related and sympatric in our study sites, but the reed warbler is a widespread long‐distance migrant while the moustached warbler's breeding range is patchier and it is resident or migrates over short distances. Using microsatellite and mtDNA data, we found higher differentiation in moustached than in reed warblers, indicating higher dispersal capability of the latter species. Our results also suggest that the sea limits dispersal in the moustached warbler. However, we found evidence of gene flow between the study sites in both species, indicating a capability to compensate for habitat fragmentation. In most cases, the gene flow was restricted, possibly because of the large distances between study sites (from c. 290 to 960 km) or breeding site fidelity. The reed warbler had higher haplotype diversity, likely due to dispersal from different populations, past admixture event and a larger population size. We found also signs of postglacial population growth for both species and evidence of a recent colonization or re‐colonization of the Mallorca Island by the moustached warbler. This article is protected by copyright. All rights reserved.
      PubDate: 2015-04-16T03:22:38.770315-05:
      DOI: 10.1111/jav.00589
  • Re‐colonization by common eiders (Somateria mollissima) in the
           Aleutian Archipelago following removal of introduced arctic foxes (Vulpes
    • Authors: Margaret R. Petersen; G. Vernon Byrd, Sarah A. Sonsthagen, Matthew G. Sexson
      Abstract: Islands provide refuges for populations of many species where they find safety from predators, but the introduction of predators frequently results in elimination or dramatic reductions in island‐dwelling organisms. When predators are removed, re‐colonization for some species occurs naturally, and inter‐island phylogeographic relationships and current movement patterns can illuminate processes of colonization. We studied a case of re‐colonization of common eiders (Somateria mollissima) following removal of introduced arctic foxes (Vulpes lagopus) in the Aleutian Archipelago, Alaska. We expected common eiders to resume nesting on islands cleared of foxes and to re‐colonize from nearby islets, islands, and island groups. We thus expected common eiders to show limited genetic structure indicative of extensive mixing among island populations. Satellite telemetry was used to record current movement patterns of female common eiders from six islands across three island groups. We collected genetic data from these and other nesting common eiders at 14 microsatellite loci and the mitochondrial DNA control region to examine population genetic structure, historical fluctuations in population demography, and gene flow. Our results suggest recent interchange among islands. Analysis of microsatellite data supports satellite telemetry data of increased dispersal of common eiders to nearby areas and little between island groups. Although evidence from mtDNA is suggestive of female dispersal among island groups, gene flow is insufficient to account for recolonization and rapid population growth. Instead, near‐by remnant populations of common eiders contributed substantially to population expansion, without which re‐colonization would have likely occurred at a much lower rate. Genetic and morphometric data of common eiders within one island group two and three decades after re‐colonization suggests reduced movement of eiders among islands and little movement between island groups after populations were re‐established. We predict that re‐colonization of an island group where all common eiders are extirpated could take decades. This article is protected by copyright. All rights reserved.
      PubDate: 2015-04-16T03:22:26.999708-05:
      DOI: 10.1111/jav.00626
  • No change in common cuckoo Cuculus canorus parasitism and great reed
           warblers' Acrocephalus arundinaceus egg rejection after seven decades
    • Abstract: The coevolutionary process among avian brood parasites and their hosts involves stepwise changes induced by the antagonistic selection pressures of one on the other. As long‐term data on an evolutionary scale is almost impossible to obtain, most studies can only show snapshots of such processes. Information on host behaviour, such as changes in egg rejection rates and the methods of rejection are scarce. In Hungary there is an interesting case between the common cuckoo (Cuculus canorus) and the great reed warbler (Acrocephalus arundinaceus), where the level of parasitism is unusually high (around 50%). We compared host rejection rates and methods of rejection from within our own project to that of an early study carried out and published almost 70 years ago in the same region. Our comparisons revealed high and stable rates of parasitism (range: 52‐64%), and marked fluctuations in the ratio of multiply parasitized nests (range: 24‐52%). No difference was revealed in egg rejection rates after 7 decades (34‐39%). Linear mixed‐effects modelling revealed no year effect on the type host responses toward the parasitic egg(s) during the years of study (categorized as acceptance, ejection, burial, and nest desertion). Cuckoo egg rejection was primarily affected by the type of parasitism, as more cuckoo eggs were rejected during single parasitism than from multiply parasitized nests. Our comparison did not reveal any directional changes in this cuckoo‐host relationship, except a slight decrease in the frequency of multiple parasitism, which is likely to be independent from coevolutionary processes. This article is protected by copyright. All rights reserved.
      PubDate: 2015-04-16T03:22:13.910489-05:
      DOI: 10.1111/jav.00673
  • Evidence for strong genetic structure in European populations of the
           little owl Athene noctua
    • Abstract: The little owl Athene noctua is a widespread species in Europe. This mainly sedentary owl experienced reduction in population sizes in some areas due to habitat loss and modification of the landscape. To assess the genetic structure of the populations of western and central Europe, we analysed 333 specimens from 15 geographical areas at 13 microsatellite loci. Statistical analyses and Bayesian clustering procedures detected two major genetically distinct clusters, the first distributed from Portugal to the Czech Republic and the second from the Balkans to Italy. The second cluster was further split into three groups, located in Italy, Sardinia and the Balkans. These groups match four previously‐described mtDNA haplogroups, and probably originated from the isolation of little owl populations in Sardinia and in three glacial refugia (Iberia, south Italy and Balkans) during the ice ages. High genetic admixture was recorded in central and northern Europe, probably as a consequence of the expansion from the refugia during interglacial. The main colonization route originated from the Iberian Peninsula towards central and northern Europe. Contact zones with colonization events from Italy and the Balkans were detected respectively in northern Italy and central Europe. Genetic indices show the existence of moderate levels of genetic variability throughout Europe, although evidence of recent evolutionary bottlenecks was found in some populations. Estimation of migration rates and approximate Bayesian computations highlighted the most likely phylogeographical scenario for the current distribution of little owl populations.
      PubDate: 2015-04-10T05:57:42.9192-05:00
      DOI: 10.1111/jav.00679
  • Stopover duration, movement patterns and temporary home ranges of fall
           migrant yellow‐rumped warblers Setophaga coronata in native and
           anthropogenic woodlands of the Northern Prairie region, USA
    • Authors: Ming Liu; David L. Swanson
      Abstract: Stopover behavior of migrant birds is influenced by their energetic condition, but also by extrinsic factors, including weather conditions and habitat attributes such as vegetation structure, microclimates, predation pressure, competition, and food availability. Anthropogenic habitats may differ from natural habitats in these attributes, which could promote differing stopover behaviors for migrants in the two habitat types and affect overall habitat suitability. We used radio‐telemetry to measure stopover behaviors of fall migrant yellow‐rumped warblers Setophaga coronata in native riparian corridor woodlands (corridors) and anthropogenic woodlots (woodlots) in the Northern Prairie region. We measured stopover duration, movement rate, and temporary home range size for birds in both habitat types by attaching radio‐transmitters and relocating birds to either corridor (n = 17) or woodlot (n = 16) study sites. We used AICC to rank null, global, and reduced models, which included habitat type, energetic condition, habitat size, year, date, and movement rate (for stopover duration analyses only) as explanatory variables. Model rankings showed that habitat type was not included in any of the top models (ΔAICC < 2) for movement behavior, temporary home range size, or stopover duration, which suggests similar functional habitat quality between the two habitat types. These data add similar behavioral responses for birds in the two habitat types to similar fattening rates and stress physiology, further confirming similar suitability of native and anthropogenic woodland habitats in this region as stopover habitat. We also applied logistic regression with a model selection approach, including cloud cover, tail wind component, temperature, and barometric pressure as independent variables, and departure decision as the dependent variable, to evaluate the effects of weather variables on departure. Model selection suggested that cloud cover is a prominent factor affecting departure decisions and the other variables may also influence departure decisions of yellow‐rumped warblers from inland stopover sites.
      PubDate: 2015-04-10T05:57:08.406263-05:
      DOI: 10.1111/jav.00672
  • Cover, not caging, influences chronic physiological stress in a
           ground‐nesting bird
    • Authors: Laura X. L. Tan; Katherine L. Buchanan, Grainne S. Maguire, Michael A. Weston
      Abstract: Predator exclosures (‘nest cages’) around nests are increasingly used to enhance hatching success of declining ground‐nesting birds. However, such exclosures are contentious and have been suggested to have detrimental effects on the species which they aim to protect. This study examines whether exclosures increase physiological stress of incubating birds, a hitherto unrecognised and untested potential drawback of exclosures. Red‐capped plover Charadrius ruficapillus hatching success was radically altered and significantly higher for nests with exclosures (96.2%) compared with those without (6.8%). Chronic physiological stress in parents (as measured by the heterophil/lymphocyte [H/L] ratio in blood) did not vary between nests with and without exclosures, or between the sexes. However the absence of vegetative cover at the nest site was associated with a 62.7% elevation in H/L ratio, indicating that incubating birds which place their nests in the open are subject to increased levels of chronic stress. The results from this study demonstrate the fundamental importance of predation for the nesting success of this species and confirm that chronic stress levels are not a detrimental side effect of exclosure use.
      PubDate: 2015-04-08T08:57:58.396807-05:
      DOI: 10.1111/jav.00625
  • Visual obstruction and vigilance: a natural experiment
    • Authors: Guy Beauchamp
      Abstract: Visual obstructions can cause an increase in antipredator vigilance in prey animals by making predator detection more difficult. However, visual obstructions can also skew the perception of group size and inter‐individual distances and impair the detection of alarm signals by conspecifics. These changes within the group alone can cause an increase in vigilance. To disentangle the contribution of these various factors to changes in vigilance, I documented vigilance in a gregarious species, the semipalmated sandpiper Calidris pusilla, foraging in a habitat where a naturally‐occurring visual barrier partially prevented predator detection without altering the transfer of information about predation risk within the group. I used a matched sampling design to collect vigilance data for birds using adjacent areas with and without the visual barrier. In the visually‐obstructed area, sandpipers maintained a higher level of vigilance, occurred farther away from cover and in smaller flocks, and preferentially scanned the area of danger with one eye in particular. All these changes suggest that visual obstruction increased perceived predation risk. I conclude that it is the inability to get a good view of any approaching predator, rather than changes in intra‐group communication that caused the increase in vigilance in the visually‐obstructed area.
      PubDate: 2015-04-08T08:57:42.197467-05:
      DOI: 10.1111/jav.00612
  • Individual seabirds show consistent foraging strategies in response to
           predictable fisheries discards
    • Authors: Samantha C. Patrick; Stuart Bearhop, Thomas W. Bodey, W. James Grecian, Keith C. Hamer, Janette Lee, Stephen C. Votier
      First page: 431
      Abstract: Current fishing extraction methods often generate huge quantities of dead or dying biomass that is returned to the sea in the form of discards. This practice produces a readily available clumped resource for many scavengers such as seabirds, but in the face of declining stocks and via policy change, the amount of discards produced is set to decline in the future. To understand how discards have influenced seabird foraging in the past and how birds may respond to future change requires studies examining consistent individual foraging choices. There is increasing evidence that populations may be made up of generalist or specialist foragers and this is key to the population's ability to adapt to change. Here we test for consistent individual foraging behaviour of northern gannets Morus bassanus in relation to fishing vessels and examine consequences of scavenging behaviour in terms of foraging effort and body condition. Using a combination of bird‐borne bio‐logging devices (GPS and Time Depth Recorders) with high resolution GPS data acquired through vessel monitoring systems on fishing boats, we examined the overlap between birds and fisheries. We found that during repeat foraging trips in the same breeding season, gannets regularly foraged at fishing boats but there were also clear among individual differences in the extent of fisheries overlap. Furthermore, we show for the first time that these differences represent consistent strategies – individual differences in scavenging were highly repeatable across multiple trips within a period of several weeks. However, despite this finding, we found no differences in foraging effort or body condition between scavengers and non‐scavengers. Moreover, scavenging strategy did not appear to influence diving behaviour or vary by sex. Scavenging on discards appears to be a strategy employed consistently by a subsection of the population and future work should examine whether these specialisations persist throughout and between years and what causes these individual differences, exploring possible demographic and fitness consequences in light of global changes to fish stocks and fisheries management.
      PubDate: 2015-04-20T05:21:00.2886-05:00
      DOI: 10.1111/jav.00660
  • Breeding season weather determines long‐tailed tit reproductive
           success through impacts on recruitment
    • Authors: Philippa R. Gullett; Ben J. Hatchwell, Robert A. Robinson, Karl L. Evans
      First page: 441
      Abstract: Productivity is a key demographic trait that can be influenced by climate change, but there are substantial gaps in our understanding of the impact of weather on productivity and recruitment in birds. Weather is known to influence reproductive success in numerous species, although such effects have not been reported in all studies, perhaps because they are masked by high nest predation rates or buffered by density dependence. Here, we use a 19‐year study of a population of individually marked Long‐tailed Tits Aegithalos caudatus to quantify the impacts of weather on productivity in the nest (from eggs to fledging) and subsequent recruitment, while taking nest predation rates and density dependence into account. We find that weather has negligible effects on clutch size, hatching success, brood size, probability of fledging and number of fledglings. Annual variation in nest predation rates is a strong predictor of productivity, but we find no evidence that the magnitude of nest predation is determined by weather. Recruitment was strongly associated with breeding season weather, even when taking density dependence effects into account. This contrasts with the conventional view that first year survival of temperate passerines is primarily determined by winter weather. Recruitment was reduced when March temperatures were high, perhaps caused by earlier peaks in caterpillar abundance and thus reduced food availability at the time of fledging. Recruitment increased following high May temperatures, perhaps due to an improved thermo‐regulatory environment for young fledglings. These opposing effects of warm March and May temperatures highlight the importance of considering asymmetrical rates of warming in different months when predicting climate change impacts. This article is protected by copyright. All rights reserved.
      PubDate: 2015-03-16T14:21:33.117658-05:
      DOI: 10.1111/jav.00560
  • Food availability modulates the effects of maternal antibodies on growth
           and immunity in young feral pigeons
    • Authors: A. Ismail; L. Jacquin, C. Haussy, S. Perret, J. Gasparini
      First page: 489
      Abstract: It is now widely acknowledged that mothers can transfer their own immune experience to their progeny through the allocation of specific maternal antibodies (hereafter referred as MatAb) that can shape offspring phenotype and affect their fitness. However, the importance of environmental variability in modulating the effects of MatAb on offspring traits is still elusive. Using an experimental approach, we investigated how food availability interacted with MatAb to solve the trade‐off between humoral immunity and growth in young feral pigeons (Columba livia). Results show that the inhibitory effect of MatAb on the humoral response of chicks was detected regardless of the food treatment. In addition, body mass growth was higher in chicks receiving lower amounts of maternal antibodies but only in chicks of the ad libitum food treatment. This contradicts previous studies and suggests that the transfer of MatAb could entail some costs for chicks and reduce their growth. Taken together these results reinforce the idea that the maternal antibodies play a central role in shaping offspring life‐history traits but that their adaptive value is highly dependent on the environmental context in which they are transmitted by the mother. This article is protected by copyright. All rights reserved.
      PubDate: 2015-04-08T08:58:17.731771-05:
      DOI: 10.1111/jav.00698
  • Carry‐over effects of winter habitat quality on en route timing and
           condition of a migratory passerine during spring migration
    • Authors: Kristina L. Paxton; Frank R. Moore
      First page: 495
      Abstract: We examined how conditions prior to migration influenced migration performance of two breeding populations of black‐and‐white warblers (Mniotilta varia) by linking information on the migrant's winter habitat quality, measured via stable carbon isotopes, with information on their breeding destination, measured via stable hydrogen isotopes. The quality of winter habitat strongly influenced the timing of migration when we accounted for differential timing of migration between breeding populations. Among birds migrating to the same breeding destination, males and females arriving early to the stopover site originated from more mesic habitat than later arriving birds, suggesting that the benefits of occupying high‐quality mesic habitat during the winter positively influence the timing of migration. However, male warblers arriving early to the stopover site were not in better migratory condition than later arriving conspecifics that originated from poor‐quality xeric winter habitat, regardless of breeding destination. The two breeding populations stopover at the study site during different time periods, suggesting that the lower migratory condition of early birds is not a function of the time of season, but potentially a migrant's migration strategy. Strong selection pressures to arrive early on the breeding grounds to secure high‐quality breeding territories may drive males from high‐quality winter habitat to minimize time at the expense of energy. This migration strategy would result in a smaller margin of safety to buffer the effects of adverse weather or scarcity of food, increasing the risk of mortality. The migratory condition of females was the same regardless of the timing of migration or breeding destination, suggesting that females adopt a strategy that conserves energy during migration. This study fills an important gap in our understanding of the linkages between winter habitat quality and factors that influence the performance of migration, the phase of the annual cycle thought to be limiting most migratory bird populations. This article is protected by copyright. All rights reserved.
      PubDate: 2015-03-17T07:46:20.974532-05:
      DOI: 10.1111/jav.00614
  • Evidence of a link between survival and pair fidelity across multiple tit
    • Authors: Antica Culina; Shelly Lachish, Ben C. Sheldon
      First page: 507
      Abstract: Although they have the potential to strongly influence individual fitness and the dynamics and productivity of populations, the survival consequences of pairing outcomes and the influence of current pairing outcomes on those in the future have rarely been addressed. Previously, we have shown that pair fidelity increases both survival and future pair fidelity in a population of great tits (Parus major). The aim of this study was to explore the generality of our previous findings by evaluating the influence of current paring outcomes on survival and on future pairing outcomes in two different species and in different populations. We addressed our aims within a multievent capture‐mark‐recapture (MECMR) statistical framework, which accounts for differences in recapture rates and uncertainty in the assignment of pair status (i.e. whether an individual is breeding with the same partner or not). We applied the framework to breeding records of two great tit populations and one blue tit (Cyanistes caeruleus) population. We detected survival benefits (i.e. increased survival) of pair fidelity in all three populations. These were similar in both great tit populations, but higher for male great tits than for male blue tits. We found that age‐dependence in the rate of pair fidelity was shared between different populations and species, but did not detect any influence of current pair status on future pair status. Our study highlights the importance of considering survival when studying the fitness benefits of pair fidelity. Some of the differences in pair fidelity rates and survival benefits of pair fidelity are likely the result of long‐term and short‐term demographic and environmental factors in the population. We advocate the use of the MECMR framework used here for further exploration of these differences. This article is protected by copyright. All rights reserved.
      PubDate: 2015-04-08T08:58:32.097969-05:
      DOI: 10.1111/jav.00661
  • Ecological niche variation in the Wilson's Warbler (Cardellina pusilla)
    • First page: 516
      Abstract: Wilson's Warbler comprises three subspecies separated into two geographic groups: C. p. pusilla that breeds in Eastern North America; and C. p. pileolata and C. p. chryseola that breed in Western North America. Given the differences between the groups in genetics, morphology, habitat use, and population decline, we tested for ecological niche similarity in both their breeding and wintering distribution using niche modeling based on temperature and precipitation data. We first conducted an inter‐prediction approach considering the percent of summer and winter localities of one group that are predicted by the potential distribution of the alternate group. We also applied a null model approach that compares self‐predictions and pseudoreplicates of each group to indicate similarity, divergence, or indeterminate niche overlap. Finally, we compared ecological distances between and within groups using the Gower similarity equation. We found that the Western group had an ecological niche of broader climatic conditions, while the Eastern group had a narrower ecological niche. The inter‐prediction approach showed that, for both summering and wintering ranges, ecological niche models of the Western group predicted ~50% of the observed distribution of the Eastern group, whereas Eastern group models predicted
      PubDate: 2015-04-10T05:57:26.447885-05:
      DOI: 10.1111/jav.00531
  • Uncommon paleodistribution patterns of Chrysolophus pheasants in East
           Asia: explanations and implications
    • First page: 528
      Abstract: Some modeling studies indicated that the past distributions of species in East Asia during the Last Interglacial (LIG) and Last Glacial Maximum (LGM) periods differ from those of European and North American species and the deviant Asian distribution pattern is known under the term ‘pre‐LGM expansion’. It represents the unusually similar distribution patterns between the current and the LGM scenario. However, there is still no satisfying explanation for this phenomenon so far. Therefore, we took the two recently separated pheasant species of genus Chrysolophus in East Asia as an example to test the pattern by performing ecological niche models. The main findings of this study include: (1) the paleodistributions of these two pheasants also corresponded to the ‘pre–LGM expansion’ pattern; (2) climatic similarity results from Mobility‐Oriented Parity analysis also revealed similar pattern for both species; (3) climate regimes of East Asia showed patterns different from those in Europe and North America in a climate shift towards drier conditions and stronger seasonality and to more extreme temperatures of the coldest months particularly during the LIG; (4) the two Chrysolophus species occupied significantly different ecological niches according to current distribution. We suggest that ecological segregation established in allopatric glacial refugia should be the main determinants for the separation of two Chrysolophus species until they came into extant post–Pleistocene contact. This article is protected by copyright. All rights reserved.
      PubDate: 2015-03-23T04:20:19.229589-05:
      DOI: 10.1111/jav.00590
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327
About JournalTOCs
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-2015