CapsuleField plots provisioned with a supplementary seed mix during summer attracted European Turtle Doves and other farmland birds, and exhibited only a low incidence of the parasite Trichomonas gallinae.AimsTo test whether Turtle Doves and other granivorous birds use field plots provided with supplementary seed, and whether use of these plots increased exposure to T. gallinae.MethodsSupplementary seed mix was provided at two rates (3 and 6 kg per 250 m2 plot) weekly at 37 sites in the spring and summer of 2016 and 2017. Provisioned plots, and similar (but unprovisioned) control areas, were surveyed for Turtle Doves and other birds. Soil swab samples were also taken and analysed for the presence of T. gallinae using a standard polymerase chain reaction procedure.ResultsTurtle Doves were much more likely to be recorded on provisioned plots than on unprovisioned control areas. Maximum counts of an aggregate of seven other granivores of conservation interest (European Greenfinch Chloris chloris, Common Linnet Linaria cannabina, Eurasian Tree Sparrow Passer montanus, House Sparrow P. domesticus, Common Reed Bunting Emberiza schoeniclus, Corn Bunting E. calandra and Yellowhammer E. citrinella) were significantly higher on provisioned plots than on control areas. Positive samples for T. gallinae were rare on provisioned plots and unprovisioned areas (eight of 474 samples across both years). Samples classified as ambiguous (due to the presence of genomic DNA that could not be definitively ascribed to T. gallinae) or positive were equally likely on provisioned plots and unprovisioned areas, but were more likely at sites where European Greenfinches were recorded.ConclusionSupplementary seed provisioning in summer can attract foraging Turtle Doves with only a low risk of exposure to T. gallinae on the feeding areas.

Telomeres are a popular biomarker of senescence, as telomere dynamics are linked with survival and lifespan. However, the evolutionary potential of telomere dynamics, and the selection pattern that gives rise to senescence, are not well known. To better understand this, it is necessary to quantify genetic variation in telomere length, and how such variation changes with age. Here, we analysed a longitudinal dataset (2,156 samples from 1,267 individuals across 15 years) from a wild, insular house sparrow (Passer domesticus) population with complete life-history and genetic relatedness data. Using a series of ‘animal’ models, we confirmed that telomere length (TL): (1) changes with age, reflecting senescence in this population. We then showed that (2) TL is repeatable (15.7%, 95% CrI: 10.2–21.0%) and heritable (14.0%, 95% CrI: 8.7–19.5%); and, for the first time in the wild, (3) that TL shows a genotype-by-age interaction, meaning that genotypes differ in their rate of TL change, where additive genetic variance increases at older ages. Our findings provide empirical evidence from a wild population that supports hypotheses explaining the evolution of senescence, and highlights the importance of telomere dynamics as a key biomarker of body physiology for the evolution of senescence.

Explaining variation in individual fitness is a key goal in evolutionary biology. Recently, telomeres, repeating DNA sequences capping the ends of chromosomes, have gained attention as a biomarker for body state, individual quality, and ageing. However, existing research has provided mixed evidence for whether telomere length correlates with fitness components, including survival and reproductive output. Moreover, few studies have examined how telomere shortening correlates with fitness in wild populations. Here, we intensively monitored an insular population of house sparrows on Lundy Island, UK, and collected longitudinal telomere and life history data spanning 16 years from 1,225 individuals. We tested whether telomere length and/or shortening predict fitness measures, namely survival, lifespan, as well as annual and lifetime reproductive success. Telomere length positively predicted immediate survival up to one year after measurement, independent of age, but did not predict lifespan, suggesting either a diminishing telomere length – survival correlation with age, or other extrinsic factors of mortality. The positive effect of telomere length on survival translated to reproductive benefits, as birds with longer telomeres produced more genetic recruits over their lifetime, but not annually, suggesting variation in individual quality. The rate of telomere shortening, however, correlated with neither lifespan nor lifetime reproductive success. Our results provided further evidence that telomere length correlates with fitness, and they contributed to our understanding of how telomere dynamics link with individual quality.

Colonization of islands by long‐distance dispersers has great impact on genetic diversification among populations and may spearhead speciation events. We investigated intra‐ and interspecific divergence in Charadrius plovers with populations on mainland Africa, Madagascar and St Helena. We analysed microsatellite loci and sequence data from four nuclear and two mitochondrial gene regions. Charadrius plovers are shorebirds with high dispersal and mobility. Our results confirmed genetic differentiation between Madagascar and mainland populations of three plover species (White‐fronted Plover Charadrius marginatus, Kittlitz's Plover Charadrius pecuarius and, based on sequence data only, Three‐banded Plover Charadrius tricollaris) but highlight substantial variation in levels of intraspecific divergence among the three species. Namely, the Kittlitz's Plover, a dispersive habitat generalist with a polygamous mating system, exhibited lower island–mainland differentiation (0.05% COI sequence divergence) compared with the two monogamous species, the White‐fronted Plover (0.6% COI divergence) and Three‐banded Plover (1.6% COI divergence). In addition, past colonization of the islands of St Helena and Madagascar by ancestors of today's Kittlitz's Plover has led to the evolution of two endemic island species, the Madagascar Plover Charadrius thoracicus and the more closely‐related St Helena Plover Charadrius sanctaehelenae. We discuss the factors driving species differences in island–mainland divergence and highlight the importance of conserving genetically unique island populations and island habitats to safeguard future evolutionary potential.

Exploring the patterns of genetic structure in the context of geographical and phenotypic variation is important to understand the evolutionary processes involved in speciation. We investigated population and subspecies differentiation in the Common Ringed Plover Charadrius hiaticula, a high latitude wader that breeds in arctic and temperate zones from northeast Canada across Eurasia to the Russian Far East. Three subspecies, hiaticula, tundrae and psammodromus, are currently widely recognised, whereas a fourth subspecies, kolymensis, has been proposed based on geographic isolation and phenotypic differences. We genotyped 173 samples from eleven Common Ringed Plover breeding sites, representing all four putative subspecies, at eight polymorphic microsatellite loci to examine the patterns of population and subspecies differentiation. Bayesian clustering identified three genetic clusters among samples, corresponding to the breeding sites of the three currently recognised subspecies. The existence of the subspecies kolymensis was not supported. We also detected the presence of a previously unknown hybridisation zone extending from Northern Scandinavia to Belarus. Differentiation of the subspecies tundrae and hiaticula most likely occurred in allopatry on the Eurasian continent during past glaciation events, followed by population expansion leading to colonisation of Iceland and Greenland. The lack of genetic differentiation within the tundrae subspecies is consistent with ongoing range expansion and high gene flow maintained through migratory behaviour. We discuss the importance of historic climate changes, migratory behaviour and mating system on shaping the observed pattern of genetic differentiation.

The Chestnut‐banded Plover Charadrius pallidus is a Near‐Threatened shorebird species endemic to mainland Africa. We examined levels of genetic differentiation between its two morphologically and geographically distinct subspecies, C. p. pallidus in southern Africa (population size 11 000–16 000) and C. p. venustus in eastern Africa (population size 6500). In contrast to other plover species that maintain genetic connectivity over thousands of kilometres across continental Africa, we found profound genetic differences between remote sampling sites. Phylogenetic network analysis based on four nuclear and two mitochondrial gene regions, and population genetic structure analyses based on 11 microsatellite loci, indicated strong genetic divergence, with 2.36% mitochondrial sequence divergence between individuals sampled in Namibia (southern Africa) and those of Kenya and Tanzania (eastern Africa). This distinction between southern and eastern African populations was also supported by highly distinct genetic clusters based on microsatellite markers (global FST = 0.309, = 0.510, D = 0.182). Behavioural factors that may promote genetic differentiation in this species include habitat specialization, monogamous mating behaviour and sedentariness. Reliance on an extremely small number of saline lakes for breeding and limited dispersal between populations are likely to promote reproductive and genetic isolation between eastern and southern Africa. We suggest that the two Chestnut‐banded Plover subspecies may warrant elevation to full species status. To assess this distinction fully, additional sample collection will be needed, with analysis of genetic and phenotypic traits from across the species’ entire breeding range.

Adult sex ratio (ASR) is a central concept in population biology and a key factor in sexual selection, but why do most demographic models ignore sex biases? Vital rates often vary between the sexes and across life history, but their relative contributions to ASR variation remain poorly understood-an essential step to evaluate sex ratio theories in the wild and inform conservation. Here, we combine structured two-sex population models with individual-based mark-recapture data from an intensively monitored polygamous population of snowy plovers. We show that a strongly male-biased ASR (0.63) is primarily driven by sex-specific survival of juveniles rather than adults or dependent offspring. This finding provides empirical support for theories of unbiased sex allocation when sex differences in survival arise after the period of parental investment. Importantly, a conventional model ignoring sex biases significantly overestimated population viability. We suggest that sex-specific population models are essential to understand the population dynamics of sexual organisms: reproduction and population growth are most sensitive to perturbations in survival of the limiting sex. Overall, our study suggests that sex-biased early survival may contribute toward mating system evolution and population persistence, with implications for both sexual selection theory and biodiversity conservation.

Extra-pair paternity is a common reproductive strategy in many bird species. However, it remains unclear why extra-pair paternity occurs and why it varies among species and populations. Plovers (Charadrius spp.) exhibit considerable variation in reproductive behaviour and ecology, making them excellent models to investigate the evolution of social and genetic mating systems. We investigated inter- and intra-specific patterns of extra-pair parentage and evaluated three major hypotheses explaining extra-pair paternity using a comparative approach based on the microsatellite genotypes of 2049 individuals from 510 plover families sampled from twelve populations that constituted eight species. Extra-pair paternity rates were very low (0 to 4.1% of chicks per population). No evidence was found in support of the sexual conflict or genetic compatibility hypotheses, and there was no seasonal pattern of extra-pair paternity (EPP). The low prevalence of EPP is consistent with a number of alternative hypotheses, including the parental investment hypothesis, which suggests that high contribution to care by males restricts female plovers from engaging in extra-pair copulations. Further studies are needed to critically test the importance of this hypothesis for mate choice in plovers.

Aim Parental care improves the survival of offspring and therefore has a major impact on reproductive success. It is increasingly recognized that coordinated biparental care is necessary to ensure the survival of offspring in hostile environments, but little is known about the influence of environmental fluctuations on parental cooperation. Assessing the impacts of environmental stochasticity, however, is essential for understanding how populations will respond to climate change and the associated increasing frequencies of extreme weather events. Here we investigate the influence of environmental stochasticity on biparental incubation in a cosmopolitan ground-nesting avian genus.Location Global.Methods We assembled data on biparental care in 36 plover populations (Charadrius spp.) from six continents, collected between 1981 and 2012. Using a space-for-time approach we investigate how average temperature, temperature stochasticity (i.e. year-to-year variation) and seasonal temperature variation during the breeding season influence parental cooperation during incubation.Results We show that both average ambient temperature and its fluctuations influence parental cooperation during incubation. Male care relative to female care increases with both mean ambient temperature and temperature stochasticity. Local climatic conditions explain within-species population differences in parental cooperation, probably reflecting phenotypic plasticity of behaviour.Main conclusions The degree of flexibility in parental cooperation is likely to mediate the impacts of climate change on the demography and reproductive behaviour of wild animal populations.

Sexual selection may act as a promotor of speciation since divergent mate choice and competition for mates can rapidly lead to reproductive isolation. Alternatively, sexual selection may also retard speciation since polygamous individuals can access additional mates by increased breeding dispersal. High breeding dispersal should hence increase gene flow and reduce diversification in polygamous species. Here, we test how polygamy predicts diversification in shorebirds using genetic differentiation and subspecies richness as proxies for population divergence. Examining microsatellite data from 79 populations in 10 plover species (Genus: Charadrius) we found that polygamous species display significantly less genetic structure and weaker isolation‐by‐distance effects than monogamous species. Consistent with this result, a comparative analysis including 136 shorebird species showed significantly fewer subspecies for polygamous than for monogamous species. By contrast, migratory behavior neither predicted genetic differentiation nor subspecies richness. Taken together, our results suggest that dispersal associated with polygamy may facilitate gene flow and limit population divergence. Therefore, intense sexual selection, as occurs in polygamous species, may act as a brake rather than an engine of speciation in shorebirds. We discuss alternative explanations for these results and call for further studies to understand the relationships between sexual selection, dispersal, and diversification.

We have developed a new marker (Z43B) that can be successfully used to identify the sex of most birds (69%), including species difficult or impossible to sex with other markers. We utilized the zebra finch Taeniopygia guttata EST microsatellite sequence (CK309496) which displays sequence homology to the 5' untranslated region (UTR) of the avian spindlin gene. This gene is known to be present on the Z and W chromosomes. To maximize cross-species utility, the primer set was designed from a consensus sequence created from homologs of CK309496 that were isolated from multiple distantly related species. Both the forward and reverse primer sequences were 100% identical to 14 avian species, including the Z chromosome of eight species and the chicken Gallus gallus W chromosome, as well as the saltwater crocodile Crocodylus porosus. The Z43B primer set was assessed by genotyping individuals of known sex belonging to 61 non-ratite species and a single ratite. The Z and W amplicons differed in size making it possible to distinguish between males (ZZ) and females (ZW) for the majority (69%) of non-ratite species tested, comprising 10 orders of birds. We predict that this marker will be useful for obtaining sex-typing data for ca 6,869 species of birds (69% of non-ratites but not galliforms). A wide range of species could be sex-typed including passerines, shorebirds, eagles, falcons, bee-eaters, cranes, shags, parrots, penguins, ducks, and a ratite species, the brown kiwi, Apteryx australis. Those species sexed include species impossible or problematic to sex-type with other markers (magpie, albatross, petrel, eagle, falcon, crane, and penguin species). Zoo Biol. 35:533-545, 2016. © 2016 The Authors. Zoo Biology published by Wiley Periodicals, Inc.

Microsatellite loci are widely used in ecological and evolutionary studies to assess inbreeding, genetic parentage and population structure. Such loci are often optimised in multiplexes to allow for economical and efficient use. Here, we tested 11 microsatellite loci designed for use in European bee-eaters (Merops apiaster), along with 31 loci isolated in other species, for their utility in European bee-eaters sampled on Susak Island, Croatia. Of these 42 loci, 20 were polymorphic in 38 individuals. These polymorphic loci were further assessed in a sub-set of 23 adults, excluding close relatives, and exhibited between three and 13 alleles each. All loci were autosomal, as indicated by the presence of heterozygotes in both males and females. One of the polymorphic loci exhibited low heterozygosity, three loci deviated from Hardy-Weinberg equilibrium and three pairs of loci displayed linkage disequilibrium. The remaining selected eight cross-species loci and seven loci isolated in European bee-eaters were combined with two sex-typing markers and optimised in five multiplexes. A combination of 15 autosomal loci of varying degrees of polymorphism makes this multiplex set particularly suitable for both parentage and spatial genetic analyses. This multiplex set therefore provides a useful toolkit for studying kin selection and population genetics in the cooperatively breeding European bee-eater and, potentially, in other closely related species.

The Crab Plover Dromas ardeola is endemic to the Indian Ocean basin and breeds on islands around the Arabian Peninsula. Unique among shorebirds, it nests in an underground burrow where it lays a single white egg and feeds one chick. We investigated sex-related differences in body size and parental care of this species in Saudi Arabia. Molecular sexing of DNA samples of 66 adult Crab Plovers indicated that 26 were males and 40 were females. Males had significantly longer bill, wing and tarsus lengths than females, confirming previously published reports on sexual size dimorphism in Eritrea. Observations of molecular-sexed adults at four nests showed that both parents fed the chicks; however, females brought food to the nest-burrow more often than males (67.6% of all cases). We found that the temperature inside active nesting burrows was relatively stable at 35.0 ±SE=0.18°C (n = 11 nests) regardless of ambient temperature just outside the burrows. This suggests that burrows serve a purpose in incubation as well as in defence from predation. In the colony, adults were seen to prevent chicks from multiple burrows from leaving the nest when their own parents had left the colony, confirming a helper breeding system. We suggest areas for future investigation to further elucidate the breeding behaviour of this enigmatic and unique burrowing shorebird.

Sexual size dimorphism (SSD) among adults is commonly observed in animals and is considered to be adaptive. However, the ontogenic emergence of SSD, i.e. the timing of divergence in body size between males and females, has only recently received attention. It is widely acknowledged that the ontogeny of SSD may differ between species, but it remains unclear how variable the ontogeny of SSD is within species. Kentish Plovers Charadrius alexandrinus and Snowy Plovers C. nivosus are closely related wader species that exhibit similar, moderate (c. 4%), male-biased adult SSD. To assess when SSD emerges we recorded tarsus length variation among 759 offspring in four populations of these species. Tarsus length of chicks was measured on the day of hatching and up to three times on recapture before fledging. In one population (Mexico, Snowy Plovers), males and females differed in size from the day of hatching, whereas growth rates differed between the sexes in two populations (Turkey and United Arab Emirates, both Kentish Plovers). In contrast, a fourth population (Cape Verde, Kentish Plovers) showed no significant SSD in juveniles. Our results suggest that adult SSD can emerge at different stages of development (prenatal, postnatal and post-juvenile) in different populations of the same species. We discuss the proximate mechanisms that may underlie these developmental differences.

Three strikingly different alternative male mating morphs (aggressive 'independents', semicooperative 'satellites' and female-mimic 'faeders') coexist as a balanced polymorphism in the ruff, Philomachus pugnax, a lek-breeding wading bird. Major differences in body size, ornamentation, and aggressive and mating behaviors are inherited as an autosomal polymorphism. We show that development into satellites and faeders is determined by a supergene consisting of divergent alternative, dominant and non-recombining haplotypes of an inversion on chromosome 11, which contains 125 predicted genes. Independents are homozygous for the ancestral sequence. One breakpoint of the inversion disrupts the essential CENP-N gene (encoding centromere protein N), and pedigree analysis confirms the lethality of homozygosity for the inversion. We describe new differences in behavior, testis size and steroid metabolism among morphs and identify polymorphic genes within the inversion that are likely to contribute to the differences among morphs in reproductive traits.

A new primer set was developed for sex-typing birds, Z37B . This primer set was designed to amplify alleles of small size to render it suitable for sex-typing degraded samples, including shed feathers. This marker successfully sex-typed 50 % of the species tested, including passerines, shorebirds, rails, seabirds, eagles and the brown kiwi Apteryx australis (allele size range =81–103 bp), and is therefore expected to be suitable for sex-typing a wide range of species. Z37B sex-typed non-degraded samples (blood), degraded tissue (dead unhatched embryos, dead nestlings and museum specimens) and samples of low quantity DNA (plucked feathers and buccal swabs). The small amplicon sizes in birds suggest that this marker will be of utility for sex-typing feathers, swabs and degraded samples from a wide range of avian species.

Establishing phylogenetic relationships within a clade can help to infer ancestral origins and indicate how widespread species reached their current biogeographic distributions. The small plovers, genus Charadrius, are cosmopolitan shorebirds, distributed across all continents except Antarctica. Here we present a global, species-level molecular phylogeny of this group based on four nuclear (ADH5, FIB7, MYO2 and RAG1) and two mitochondrial (COI and ND3) genes, and use the phylogeny to examine the biogeographic origin of the genus. A Bayesian multispecies coalescent approach identified two major clades (CRD I and CRD II) within the genus. Clade CRD I contains three species (Thinornis novaeseelandiae, Thinornis rubricollis and Eudromias morinellus), and CRD II one species (Anarhynchus frontalis), that were previously placed outside the Charadrius genus. In contrast to earlier work, ancestral area analyses using parsimony and Bayesian methods supported an origin of the Charadrius plovers in the Northern hemisphere. We propose that major radiations in this group were associated with shifts in the range of these ancestral plover species, leading to colonisation of the Southern hemisphere.

During the 1950s and 1970s the osprey (Pandion haliaetus) experienced a dramatic population crash and remains of conservation concern in several parts of the world. We isolated 37 microsatellite loci and assessed these in ospreys sampled in the UK and Norway (using mouth swabs/feathers). From 26 loci variable in four ospreys, we selected 13, combined these into two multiplex-PCR sets and included a sex-typing marker. Additional markers confirmed sexes. In 17 ospreys, feather-sampled in central Norway, we found 3–10 alleles per locus. The 13 loci are autosomal (heterozygotes were present in both sexes) and observed heterozygosities ranged from 0.24 to 0.94. The combined probability of identity for the 13 loci was 8.0 × 10−12. These microsatellite loci will be useful for genetic monitoring, parentage analysis and population genetic studies of the osprey.

Mating opportunities may differ between closely related species, although the evidence for such variation is scant. Here we compare remating opportunities and courtship behaviour between three shorebird species: the Kentish plover, Charadrius alexandrinus, the Kittlitz's plover, Charadrius pecuarius, and the white-fronted plover, Charadrius marginatus, using data and an experimental approach from a previous study of the Kentish plover. By experimentally creating unmated males and females, we found that remating opportunities differed between these closely related plover species: remating times were shorter for females than males in a Kentish plover population that had a male-biased adult sex ratio, and in which most brood care after hatching was carried out by males. In contrast, remating times were male-biased in the uniparental Kittlitz's plover and unbiased in the biparental white-fronted plover. Male Kentish plovers spent significantly more time on courtship than females, whereas courtship behaviour was not sex biased in the other two plover species. The mate removal experiments also provided insights into pair bond stability. In the Kittlitz's plover, all 16 newly formed pairs remained together after the release of their former mates from captivity, whereas newly established pairs were replaced by their former mates upon release in all 12 white-fronted plover pairs. Taken together, these results are important in highlighting interspecific variation in mating activities, and suggest that both operational sex ratio and pair bond stability may differ between closely related species. These variations, in turn, may influence mating systems and parental care. (C) 2014 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.