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In migratory animals, high mobility may reduce population structure through increased dispersal and enable adaptive responses to environmental change, whereas rigid migratory routines predict low dispersal, increased structure, and limited flexibility to respond to change. We explore the global population structure and phylogeographic history of the bar‐tailed godwit, Limosa lapponica, a migratory shorebird known for making the longest non‐stop flights of any landbird. Using nextRAD sequencing of 14,318 single‐nucleotide polymorphisms and scenario‐testing in an Approximate Bayesian Computation framework, we infer that bar‐tailed godwits existed in two main lineages at the last glacial maximum, when much of their present‐day breeding range persisted in a vast, unglaciated Siberian‐Beringian refugium, followed by admixture of these lineages in the eastern Palearctic. Subsequently, population structure developed at both longitudinal extremes: in the east, a genetic cline exists across latitude in the Alaska breeding range of subspecies L. l. baueri; in the west, one lineage diversified into three extant subspecies L. l. lapponica, taymyrensis, and yamalensis, the former two of which migrate through previously glaciated western Europe. In the global range of this long‐distance migrant, we found evidence of both (1) fidelity to rigid behavioural routines promoting fine‐scale geographic population structure (in the east) and (2) flexibility to colonise recently available migratory flyways and non‐breeding areas (in the west). Our results suggest that cultural traditions in highly mobile vertebrates can override the expected effects of high dispersal ability on population structure, and provide insights for the evolution and flexibility of some of the world's longest migrations. [ABSTRACT FROM AUTHOR]

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Advancing breeding phenology is a commonly observed response to climate warming among bird species, potentially in response to shifts in the phenology of key resources. However, for migratory birds breeding at high latitudes, their capacity to breed earlier may be constrained by the time available between arrival on the breeding grounds and nesting, especially for later‐arriving individuals. This may have consequences for productivity, as early laying is often linked to higher breeding success, particularly in such seasonal environments. We investigated how migratory arrival timing influences subsequent timing of breeding, in particular whether the time between arrival and laying (arrival–laying gap) varies with arrival date, and if later‐arriving individuals are able to catch up with early‐arriving conspecifics. We tracked individual Icelandic Black‐tailed Godwit Limosa limosa islandica with GPS and PTT tags for one to two complete breeding seasons between 2013 and 2022. After arrival in Iceland, most Godwits visited their breeding territory within 5 days, though this interval was longer for earlier‐arriving birds. The total gap between arrival and laying was also longer for earlier‐arriving birds, such that laying date did not vary significantly with arrival date. These results suggest that, despite individual consistency in migratory phenology, subsequent timing of nesting is probably influenced by other factors, such as mate arrival timing and/or annual variation in environmental conditions. Regular pre‐nesting visits to the breeding territory may indicate that Godwits are able to monitor such factors closely and to nest early when conditions allow, but a larger sample of individuals and years is needed to assess whether early‐arriving individuals contribute disproportionately to population‐level advances in breeding phenology. Widespread tracking with high temporal and spatial resolution helps improve our understanding of phenological variation during the breeding season and its consequences for productivity and variation in juvenile phenology. [ABSTRACT FROM AUTHOR]

Climate change is expected to increase the spatial autocorrelation of temperature, resulting in greater synchronization of climate variables worldwide. Possibly such 'homogenization of the world' leads to elevated risks of extinction and loss of biodiversity. In this study, we develop an empirical example on how increasing synchrony of global temperatures can affect population structure in migratory animals. We studied two subspecies of bar‐tailed godwits Limosa lapponica breeding in tundra regions in Siberia: yamalensis in the west and taymyrensis further east and north. These subspecies share pre‐ and post‐breeding stopover areas, thus being partially sympatric, but exhibiting temporal segregation. The latter is believed to facilitate reproductive isolation. Using satellite tracking data, we show that migration timing of both subspecies is correlated with the date of snowmelt in their respective breeding sites (later at the taymyrensis breeding range). Snow‐cover satellite images demonstrate that the breeding ranges are on different climate trajectories and become more synchronized over time: between 1997 and 2020, the date of snowmelt advanced on average by 0.5 days/year in the taymyrensis breeding range, while it remained stable in the yamalensis breeding range. Previous findings showed how taymyrensis responded to earlier snowmelt by advancing arrival and clutch initiation. In the predicted absence of such advancements in yamalensis, we expect that the two populations will be synchronized by 2036–2040. Since bar‐tailed godwits are social migrants, this raises the possibility of population exchange and prompts the question whether the two subspecies can maintain their geographic and morphological differences and population‐specific migratory routines. The proposed scenario may apply to a wide range of (social) migrants as temporal segregation is crucial for promoting and maintaining reproductive isolation in many (partially sympatric) migratory populations. Homogenization of previously isolated populations could be an important consequence of increasing synchronized environments and hence climate change. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Animal Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Along Africa's western coast, many local communities rely on the ocean for their livelihood. Over the last decades, introductions of new fishing techniques along with globalizing trade have strongly changed local fishing practices.The Parc National du Banc d'Arguin (PNBA) in Mauritania had for centuries been subjected to an artisanal, low‐impact, fishery. This fishing was exclusively oriented towards migratory bony fish species, mullet (Mugil cephalus) and meagre (Argyrosomus regius). Since the 1980s, these species have been replaced by illegal catches of internationally traded elasmobranchs (sharks and rays) and by non‐migratory and relict species (resident) such as tilapias (Sarotherodon melanotheron) and catfishes (Arius sp.).To date, most monitoring and management efforts have been dedicated to evaluating changes in elasmobranch populations and less focus has been on bony fish species. Data from a fishery monitoring programme are used to analyse the trends in effort, catch and catch per unit of effort of bony fish species by fitting non‐parametric generalized additive models to capture changes in the fish community over the last 20 years.Mullet and meagre became overfished early on, and the contribution of resident species (tilapias and catfishes) increased in the catches. Together with a pattern of increased effort on the traditionally targeted species, such a change in the catch could reflect a change in the fish community.These results call for the implementation of sustainable fishing practices within PNBA. We propose the need to implement closures of fisheries during the species' breeding periods as well as the use of biological reference points such as the size at first capture and maximum sustainable yield targets for resident species. [ABSTRACT FROM AUTHOR]

Triggered by the disappearance of the bivalve‐eating red knots Calidris canutus from feeding areas in the western Dutch Wadden Sea after these intertidal flats were exposed to the harvesting of edible cockles Cerastoderma edule by shallow‐draft suction dredging vessels, the admission of such dredging practices in this state nature monument, RAMSAR‐site and area designated protection under the EC Habitat and Bird Directives became an issue of politicized and heated societal debate in the 1990s and early 2000s. In the absence of focussed scientific research yielding peer‐reviewed papers, the few published studies on the issue were 'side‐products' of a long‐term study on foraging ecology and population dynamics of red knots.In their contribution, van der Meer and Folmer criticized some of the statistical analyses in, what they consider, key papers leading to the closure of these forms of shellfish‐harvesting in the Dutch Wadden Sea.The material provided by van der Meer and Folmer represents useful hindsight, further analytical sophistication and a (in our view biased) literature review, and thus raises new issues of concern, while leaving intact the arguments for concern about harmful ecological effects of large‐scale suction‐dredging in protected intertidal areas.Policy implications. We conclude that, even in the light of the statistical concerns expressed by van der Meer and Folmer, there is still reasonable doubt on an absence of harmful ecological effects of suction‐dredging. This means that the eventual precautionary ruling on suction‐dredging for cockles in the protected Dutch Wadden Sea would remain perfectly valid. [ABSTRACT FROM AUTHOR]

With its focus on wetlands, the Ramsar Convention provides the clearest global agreement helping the conservation of migratory waterbirds. Two specific criteria (5 and 6) support the scientific basis for sites to achieve Ramsar recognition based on waterbird counts, while criterion 4, on species and ecological communities, also plays a role. Other international conventions and agreements follow these criteria. We identify several reasons why the listing thus established can only "catch" the absolute minimum wetland network for the conservation of migratory waterbirds. We argue that individual tracking and modern observational tools allow to better delineate the areas needed to effectively give migratory waterbird populations full life cycle protection. The sophisticated techniques to measure population characteristics now available should be used to modernize the guidance for the application of Criteria 4 and 6 of the Ramsar Convention for waterbirds, based on (i) time spent in a site throughout migration; (ii) critical ("untouchable") sites; (iii) robustness of designated site network including buffer areas; (iv) full life cycle information—including early life phases; and (v) refuges used on‐and‐off during migration in emergency situations. In these enhanced ways, migratory waterbirds can enact their roles as effective sentinels of the ecological state of the world. [ABSTRACT FROM AUTHOR]

Copyright of Global Change Biology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Applied Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Satellite and GPS tracking technology continues to reveal new migration patterns of birds which enables comparative studies of migration strategies and distributional information useful in conservation. Bar‐tailed godwits in the East Asian–Australasian Flyway Limosa lapponica baueri and L. l. menzbieri are known for their long non‐stop flights, however these populations are in steep decline. A third subspecies in this flyway, L. l. anadyrensis, breeds in the Anadyr River basin, Chukotka, Russia, and is morphologically distinct from menzbieri and baueri based on comparison of museum specimens collected from breeding areas. However, the non‐breeding distribution, migration route and population size of anadyrensis are entirely unknown. Among 24 female bar‐tailed godwits tracked in 2015–2018 from northwest Australia, the main non‐breeding area for menzbieri, two birds migrated further east than the rest to breed in the Anadyr River basin, i.e. they belonged to the anadyrensis subspecies. During pre‐breeding migration, all birds staged in the Yellow Sea and then flew to the breeding grounds in the eastern Russian Arctic. After breeding, these two birds migrated southwestward to stage in Russia on the Kamchatka Peninsula and on Sakhalin Island en route to the Yellow Sea. This contrasts with the other 22 tracked godwits that followed the previously described route of menzbieri, i.e. they all migrated northwards to stage in the New Siberian Islands before turning south towards the Yellow Sea, and onwards to northwest Australia. Since the Kamchatka Peninsula was not used by any of the tracked menzbieri birds, the 4500 godwits counted in the Khairusova–Belogolovaya estuary in western Kamchatka may well be anadyrensis. Comparing migration patterns across the three bar‐tailed godwits subspecies, the migration strategy of anadyrensis lies between that of menzbieri and baueri. Future investigations combining migration tracks with genomic data could reveal how differences in migration routines are evolved and maintained. [ABSTRACT FROM AUTHOR]

Recent technological advancements allow researchers to measure electrophysiological parameters of animals, such as sleep, in remote locations by using miniature dataloggers. Yet, continuous recording of sleep might be constrained by the memory and battery capacity of the recording devices. These limitations can be alleviated by recording intermittently instead of continuously, distributing the limited recording capacity over a longer period. We assessed how reduced sampling of sleep recordings affected measurement precision of NREM sleep, REM sleep, and Wake. We analysed a dataset on sleep in barnacle geese that we resampled following 12 different recording schemes, with data collected for 1 min per 5 min up to 1 min per 60 min in steps of 5 min. Recording 1 min in 5 min still yielded precise estimates of hourly sleep–wake values (correlations of 0.9) while potentially extending the total recording period by a factor of 5. The correlation strength gradually decreased to 0.5 when recording 1 min per 60 min. For hourly values of Wake and NREM sleep, the correlation strength in winter was higher compared with summer, reflecting more fragmented sleep in summer. Interestingly for hourly values of REM sleep, correlations were unaffected by season. Estimates of total 24 h sleep–wake values were similar for all intermittent recording schedules compared to the continuous recording. These data indicate that there is a large safe range in which researchers can periodically record sleep. Increasing the sample size while maintaining precision can substantially increase the statistical power, and is therefore recommended whenever the total recording time is limited. [ABSTRACT FROM AUTHOR]

1. Misidentification of marked individuals is unavoidable in most studies of wild animal populations. Models commonly used for the estimation of survival from such capture–recapture data ignore misidentification errors potentially resulting in biased parameter estimates. With a simulation study, we show that ignoring misidentification in Cormack–Jolly– Seber (CJS) models results in systematic positive biases in the estimates of survival and in spurious declines of survival over time. 2. We developed an extended robust design capture mark–resight (RDM) model that includes correct identification parameters to get unbiased survival estimates when resighting histories are prone to misidentification. The model assumes that resightings occur repeatedly within a season, which in practice is often the case when resightings of colour-marked individuals are collected. We implemented the RDM model in a state-space formulation and also an approximate, but computationally faster, model (RDMa) in JAGS and evaluated their performances using simulated and empirical capture–resight data on black-tailed godwits Limosa limosa. 3. The CJS models applied to simulated data under an imperfect identification scenario data produced strongly positively biased estimates of survival. For a range of degrees of correct identification probabilities, the RDM model provided unbiased and accurate estimates of survival, reencounter and correct-identification probabilities. The RDMa model performed well for large datasets (>25 individuals), with high resighting (>0.3) and high correct identification(>0.7) probabilities. For the empirical data, the CJS model estimated average juvenile survival at 0.997% and adult survival at 0.939% and also detected a strong decline in adult survival over time at a rate of −0.14 ± 0.029. In contrast, the RDMa model estimated a probability of correct identification of 0.94, annual juvenile survival at 0.234%, adult at 0.834% and less strong decline over time (−0.046 ± 0.016). 4. We conclude that estimates of survival probabilities obtained from data that include misidentification errors and analysed with standard CJS model are unlikely to be correct. The bias in survival increases with the magnitude of misidentification errors, which is inevitable as datasets become longer. Since misidentification due to tag misreads is common in empirical data, we recommend the use of the here presented RDM model to provide unbiased parameter estimates. [ABSTRACT FROM AUTHOR]

Long‐distance migratory species often include multiple breeding populations, with distinct migration routes, wintering areas and annual‐cycle timing. Detailed knowledge on population structure and migratory connectivity provides the basis for studies on the evolution of migration strategies and for species conservation. Currently, five subspecies of Bar‐tailed Godwits Limosa lapponica have been described. However, with two apparently separate breeding and wintering areas, the taxonomic status of the subspecies L. l. taymyrensis remains unclear. Here we compare taymyrensis Bar‐tailed Godwits wintering in the Middle East and West Africa, respectively, with respect to migration behaviour, breeding area, morphology and population genetic differentation in mitochondrial DNA. By tracking 52 individuals from wintering and staging areas over multiple years, we show that Bar‐tailed Godwits wintering in the Middle East bred on the northern West‐Siberian Plain (n = 19), while birds from West Africa bred further east, mostly on the Taimyr Peninsula (n = 12). The two groups differed significantly in body size and shape, and also in the timing of both northward and southward migrations. However, they were not genetically differentiated, indicating that the phenotypic (i.e. geographical, morphological and phenological) differences arose either very recently or without current reproductive isolation. We conclude that the taymyrensis taxon consists of two distinct populations with mostly non‐overlapping flyways, which warrant treatment as separate taxonomic units. We propose to distinguish a more narrowly defined taymyrensis subspecies (i.e. the Bar‐tailed Godwits wintering in West Africa and breeding on Taimyr), from a new subspecies (i.e. the birds wintering in the Middle East and breeding on the northern West‐Siberian Plain). [ABSTRACT FROM AUTHOR]

Present‐day ecology and population structure are the legacies of past climate and habitat perturbations, and this is particularly true for species that are widely distributed at high latitudes. The red knot, Calidris canutus, is an arctic‐breeding, long‐distance migratory shorebird with six recognized subspecies defined by differences in morphology, migration behavior, and annual cycle phenology, in a global distribution thought to have arisen just since the last glacial maximum (LGM). We used nextRAD sequencing of 10,881 single‐nucleotide polymorphisms (SNPs) to assess the neutral genetic structure and phylogeographic history of 172 red knots representing all known global breeding populations. Using population genetics approaches, including model‐based scenario‐testing in an approximate Bayesian computation (ABC) framework, we infer that red knots derive from two main lineages that diverged ca. 34,000 years ago, and thus most probably persisted at the LGM in both Palearctic and Nearctic refugia, followed by at least two instances of secondary contact and admixture. Within two Beringian subspecies (C. c. roselaari and rogersi), we detected previously unknown genetic structure among sub‐populations sharing a migratory flyway, reflecting additional complexity in the phylogeographic history of the region. Conversely, we found very weak genetic differentiation between two Nearctic populations (rufa and islandica) with clearly divergent migratory phenotypes and little or no apparent contact throughout the annual cycle. Together, these results suggest that relative gene flow among migratory populations reflects a complex interplay of historical, geographical, and ecological factors. [ABSTRACT FROM AUTHOR]

Longitudinal tracking studies have revealed consistent differences in the migration patterns of individuals from the same populations. The sources or processes causing this individual variation are largely unresolved. As a result, it is mostly unknown how much, how fast and when animals can adjust their migrations to changing environments.We studied the ontogeny of migration in a long‐distance migratory shorebird, the black‐tailed godwit Limosa limosa limosa, a species known to exhibit marked individuality in the migratory routines of adults. By observing how and when these individual differences arise, we aimed to elucidate whether individual differences in migratory behaviour are inherited or emerge as a result of developmental plasticity.We simultaneously tracked juvenile and adult godwits from the same breeding area on their south‐ and northward migrations. To determine how and when individual differences begin to arise, we related juvenile migration routes, timing and mortality rates to hatch date and hatch year. Then, we compared adult and juvenile migration patterns to identify potential age‐dependent differences.In juveniles, the timing of their first southward departure was related to hatch date. However, their subsequent migration routes, orientation, destination, migratory duration and likelihood of mortality were unrelated to the year or timing of migration, or their sex. Juveniles left the Netherlands after all tracked adults. They then flew non‐stop to West Africa more often and incurred higher mortality rates than adults. Some juveniles also took routes and visited stopover sites far outside the well‐documented adult migratory corridor. Such juveniles, however, were not more likely to die.We found that juveniles exhibited different migratory patterns than adults, but no evidence that these behaviours are under natural selection. We thus eliminate the possibility that the individual differences observed among adult godwits are present at hatch or during their first migration. This adds to the mounting evidence that animals possess the developmental plasticity to change their migration later in life in response to environmental conditions as those conditions are experienced. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Animal Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In seasonal environments subject to climate change, organisms typically show phenological changes. As these changes are usually stronger in organisms at lower trophic levels than those at higher trophic levels, mismatches between consumers and their prey may occur during the consumers' reproduction period. While in some species a trophic mismatch induces reductions in offspring growth, this is not always the case. This variation may be caused by the relative strength of the mismatch, or by mitigating factors like increased temperature‐reducing energetic costs. We investigated the response of chick growth rate to arthropod abundance and temperature for six populations of ecologically similar shorebirds breeding in the Arctic and sub‐Arctic (four subspecies of Red Knot Calidris canutus, Great Knot C. tenuirostris and Surfbird C. virgata). In general, chicks experienced growth benefits (measured as a condition index) when hatching before the seasonal peak in arthropod abundance, and growth reductions when hatching after the peak. The moment in the season at which growth reductions occurred varied between populations, likely depending on whether food was limiting growth before or after the peak. Higher temperatures led to faster growth on average, but could only compensate for increasing trophic mismatch for the population experiencing the coldest conditions. We did not find changes in the timing of peaks in arthropod availability across the study years, possibly because our series of observations was relatively short; timing of hatching displayed no change over the years either. Our results suggest that a trend in trophic mismatches may not yet be evident; however, we show Arctic‐breeding shorebirds to be vulnerable to this phenomenon and vulnerability to depend on seasonal prey dynamics. [ABSTRACT FROM AUTHOR]

Migratory shorebirds are among the most threatened groups of birds. They rely on natural intertidal habitats outside the breeding season, but, to some extent have adjusted to using man‐made habitats. Here, we assessed the importance of coastal saltpans – a type of anthropogenic wetland – for feeding in migratory shorebirds during their northward migration along the East Asian‐Australasian Flyway (EAAF). We combined low tide counts on intertidal flats and nearby saltpans at the Luannan coastal wetland complex (Bohai Bay, China) with Bayesian mixing model analyses (BMMs) based on stable isotopes to evaluate the relative importance of coastal saltpans versus natural intertidal habitats as foraging grounds for migrating species. We grouped shorebird species (n = 24) according to feeding guild and body size, and found that both predictors explained the broad‐scale patterns of foraging use of saltpans by shorebirds at low tide. The guild of water‐surface foraging species (e.g. stilts and avocets), independently of body size, mostly fed in saltpans, and the small‐medium visual (e.g. plovers) and tactile‐surface (e.g. sandpipers) foraging species consumed a significant portion of their diet in this habitat. In contrast, most large tactile‐surface foraging species barely foraged in saltpans at low tide. BMMs showed that shorebirds had a greater reliance on saltpans than did traditional counts of foraging birds in each habitat at low tide. Saltpan food is rich in essential fatty acids, so the contribution of saltpans to the diet of shorebirds should not be considered only in absolute values, but also in the quality of this contribution. Saltpans may therefore help conserve declining shorebirds if properly managed – for example by controlling water levels – to serve the specific feeding guilds that rely on them. While our focus is in the EAAF, the findings are relevant for other flyways and other non‐tidal anthropogenic wetlands. [ABSTRACT FROM AUTHOR]

The ecological reasons for variation in avian migration, with some populations migrating across thousands of kilometres between breeding and non‐breeding areas with one or few refuelling stops, in contrast to others that stop more often, remain to be pinned down. Red Knots Calidris canutus are a textbook example of a shorebird species that makes long migrations with only a few stops. Recognizing that such behaviours are not necessarily species‐specific but determined by ecological context, we here provide a description of the migrations of a relatively recently described subspecies (piersmai). Based on data from tagging of Red Knots on the terminal non‐breeding grounds in northwest Australia with 4.5‐ and 2.5‐g solar‐powered Platform Terminal Transmitters (PTTs) and 1.0‐g geolocators, we obtained information on 19 route‐records of 17 individuals, resulting in seven complete return migrations. We confirm published evidence that Red Knots of the piersmai subspecies migrate from NW Australia and breed on the New Siberian Islands in the Russian Arctic and that they stage along the coasts of southeastern Asia, especially in the northern Yellow Sea in China. Red Knots arrived on the tundra breeding grounds from 8 June onwards. Southward departures mainly occurred in the last week of July and the first week of August. We documented six non‐stop flights of over c. 5000 km (with a maximum of 6500 km, lasting 6.6 days). Nevertheless, rather than staging at a single location for multiple weeks halfway during migration, piersmai‐knots made several stops of up to a week. This was especially evident during northward migration, when birds often stopped along the way in southeast Asia and 'hugged' the coast of China, thus flying an additional 1000–1500 km compared with the shortest possible (great circle route) flights between NW Australia and the Yellow Sea. The birds staged longest in areas in northern China, along the shores of Bohai Bay and upper Liaodong Bay, where the bivalve Potamocorbula laevis, known as a particularly suitable food for Red Knots, was present. The use of multiple food‐rich stopping sites during northward migration by piersmai is atypical among subspecies of Red Knots. Although piersmai apparently has the benefit of multiple suitable stopping areas along the flyway, it is a subspecies in decline and their mortality away from the NW Australian non‐breeding grounds has been elevated. [ABSTRACT FROM AUTHOR]

Aim: Molluscs are important grazers, filter and deposit feeders, scavengers and predators, which in turn are food for shorebirds, fish and people. Some species, targeted as human food, have been cultured along the Chinese coast for hundreds of years. To examine whether aquacultural practices have meanwhile affected biodiversity gradients, we measured mollusc community structure along the coast of China in habitats which are intensively used by humans. Location: Chinese coast. Methods: We sampled 21 intertidal sites spanning 20 latitudinal degrees and 18,400 km of coastline. We assessed alpha diversity to verify whether mollusc communities exhibit the expected biodiversity gradient with latitude and beta diversity gradients with distance. To examine whether human activities such as transportation and culturing could have affected these patterns, we distinguished commercial from non‐commercial mollusc species and compared the differences in distribution, density, alpha diversity and beta diversity. Results: We found non‐commercial species showed the expected biodiversity gradients. Commercial species (a) dominated the intertidal mollusc communities at 19 of the 21 sites and compared with non‐commercial species, (b) exhibited wider geographical distributions, (c) showed no significant change in Bray‐Curtis index (abundance‐based beta diversity) with either geographical or climatic distance, (d) exhibited lower average dissimilarities and (e) did not show a decrease in species richness and Shannon diversity with latitude. Combining all species, trends were the same as for the commercial species. Main conclusions: A few cultured species dominated the intertidal mollusc communities in high densities along the Chinese coastline, taking over the ecological roles of the native species but not driving them extinct. In this way, aquacultural practices have exerted a homogenizing influence strong enough to erase basic biodiversity gradients. Since molluscs are food for the growing human population and the shrinking populations of migratory animals, coastal planning and management of both intertidal habitats and the exploitative activities employed need to incorporate these dimensions. [ABSTRACT FROM AUTHOR]

Occurring across Eurasia, the Black‐tailed Godwit Limosa limosa has three recognized subspecies, melanuroides, limosa and islandica from east to west, respectively. With the smallest body size, melanuroides has been considered the only subspecies in the East Asian‐Australasian Flyway. Yet, observations along the Chinese coast indicated the presence of distinctively large individuals. Here we compared the morphometrics of these larger birds captured in northern Bohai Bay, China, with those of the three known subspecies and explore the genetic population structuring of Black‐tailed Godwits based on the control region of the mitochondrial genome (mtDNA). We found that the Bohai Godwits were indeed significantly larger than melanuroides, resembling limosa more than islandica, but with relatively longer bills than islandica. The level of genetic differentiation between Bohai Godwits and the three recognized subspecies was of similar magnitude to the differentiation among previously recognized subspecies. Based on these segregating morphological and genetic characteristics, we propose that these birds belong to a distinct population, which may be treated and described as a new subspecies. [ABSTRACT FROM AUTHOR]

Despite the wealth of studies on seasonal movements of birds between southern nonbreeding locations and High Arctic breeding locations, the key mechanisms of navigation during these migrations remain elusive. A flight along the shortest possible route between pairs of points on a sphere ('orthodrome') requires a bird to be able to assess its current location in relation to its migration goal and to make continuous adjustment of heading to reach that goal. Alternatively, birds may navigate along a vector with a fixed orientation ('loxodrome') based on magnetic and/or celestial compass mechanisms. Compass navigation is considered especially challenging for summer migrations in Polar regions, as continuous daylight and complexity in the geomagnetic field may complicate the use of both celestial and magnetic compasses here. We examine the possible use of orientation mechanisms during migratory flights across the Greenland Icecap. Using a novel 2 g solar‐powered satellite transmitter, we documented the flight paths travelled by a female red knot Calidris canutus islandica during two northward and two southward migrations. The geometry of the paths suggests that red knots can migrate across the Greenland Icecap along the shortest‐, orthodrome‐like, path instead of the previously suggested loxodrome path. This particular bird's ability to return to locations visited in a previous year, together with its sudden course changes (which would be appropriate responses to ambient wind fields), suggest a map sense that enables red knots to determine location, so that they can tailor their route depending on local conditions. [ABSTRACT FROM AUTHOR]

Migratory shorebirds show highly organized seasonal cycles in physiological and morphological traits (body mass and composition, plumage, hormone levels, etc.), which in captivity is accompanied by restless behaviour at times when free‐living birds would start migration. We introduce the idea that seasonally changing preference for habitat could motivate migrants to embark on migration and that this cognitive process could also guide them to seasonally appropriate places. We explored this by testing whether red knots (Calidris canutus), which also in captivity maintain marked circannual phenotypic rhythms, show evidence of seasonal change in preference for pictures of seasonally appropriate habitats. We first developed a method to verify whether red knots are able to memorize and discriminate contrasting pictures projected by LCD projectors. This was followed by two different experiments in which we tested for a seasonally changing preference for breeding or non‐breeding habitat. When carried out during the pre‐breeding season, the red knots are expected to prefer pictures of mudflats, their non‐breeding habitat. At the start of the breeding season, they should prefer pictures of the tundra breeding habitat. We established that knots are able to distinguish and memorize projected images. We failed to demonstrate the predicted change in vision‐based habitat preference, but for reasons of test design we do not interpret this as a strong rejection of the hypothesis. Instead, we suggest that experiments with greater numbers of individuals tested once, perhaps in combination with the provision of additional cues such as smells and sounds, will help the development of these ideas further. [ABSTRACT FROM AUTHOR]

In an attempt to encourage the discourse on sources of individual variation in seasonal migration patterns and the microevolution of bird migration, we here critically examine the published interpretations of a now classic displacement study with starlings Sturnus vulgaris. Based on the ring recoveries after experimental displacement towards the south and southeast of Dutch capture sites of over 18 000 hatch‐year and older starlings, in a series of analyses published in Ardea from 1958 to 1983, A. C. Perdeck established that displaced starlings showed appropriately changed orientations only when they were experienced. During both southward and northward migration, released adults navigated to an apparently previously learned goal (i.e. the wintering or the breeding area) by showing appropriately changed orientations. Juveniles showed appropriate directions when returning to the breeding grounds. In contrast, during their first southward migration displaced juveniles carried on in the direction (and possibly the distance) expected for their release at the Dutch capture site. From the mid‐1970s this work has become cited as evidence for starlings demonstrating 'innate' migratory directions. If the definition of innateness is 'not learned by the individual itself', then there is a range of non‐innate influences on development that are not ruled out by Perdeck's experimental outcomes. For example, young starlings might have carried on in the direction that they learned to migrate before being caught, e.g. by observing the migratory directions of experienced conspecifics. We argue that, despite over 60 citations to Perdeck as demonstrating innate migratory directions, the jury is out. [ABSTRACT FROM AUTHOR]

Long‐term population studies can identify changes in population dynamics over time. However, to realize meaningful conclusions, these studies rely on accurate measurements of individual traits and population characteristics. Here, we evaluate the accuracy of the observational methods used to measure reproductive traits in individually marked black‐tailed godwits (Limosa limosa limosa). By comparing estimates from traditional methods with data obtained from light‐level geolocators, we provide an accurate estimate of the likelihood of renesting in godwits and the repeatability of the lay dates of first clutches. From 2012 to 2018, we used periods of shading recorded on the light‐level geolocators carried by 68 individual godwits to document their nesting behaviour. We then compared these estimates to those simultaneously obtained by our long‐term observational study. We found that among recaptured geolocator‐carrying godwits, all birds renested after a failed first clutch, regardless of the date of nest loss or the number of days already spent incubating. We also found that 43% of these godwits laid a second replacement clutch after a failed first replacement, and that 21% of these godwits renested after a hatched first clutch. However, the observational study correctly identified only 3% of the replacement clutches produced by geolocator‐carrying individuals and designated as first clutches a number of nests that were actually replacement clutches. Additionally, on the basis of the observational study, the repeatability of lay date was 0.24 (95% CI 0.17–0.31), whereas it was 0.54 (95% CI 0.28–0.75) using geolocator‐carrying individuals. We use examples from our own and other godwit studies to illustrate how the biases in our observational study discovered here may have affected the outcome of demographic estimates, individual‐level comparisons, and the design, implementation and evaluation of conservation practices. These examples emphasize the importance of improving and validating field methodologies and show how the addition of new tools can be transformational. [ABSTRACT FROM AUTHOR]

Evolutionary theories of seasonal migration generally assume that the costs of longer migrations are balanced by benefits at the non‐breeding destinations.We tested, and rejected, the null hypothesis of equal survival and timing of spring migration for High Arctic breeding sanderling Calidris alba using six and eight winter destinations between 55°N and 25°S, respectively.Annual apparent survival was considerably lower for adult birds wintering in tropical West Africa (Mauritania: 0.74 and Ghana: 0.75) than in three European sites (0.84, 0.84 and 0.87) and in subtropical Namibia (0.85). Moreover, compared with adults, second calendar‐year sanderlings in the tropics, but not in Europe, often refrained from migrating north during the first possible breeding season. During northward migration, tropical‐wintering sanderlings occurred at their final staging site in Iceland 5–15 days later than birds wintering further north or south. Namibia‐wintering sanderlings tracked with solar geolocators only staged in West Africa during southward migration.The low annual survival, the later age of first northward migration and the later passage through Iceland during northward migration of tropical‐wintering sanderlings, in addition to the skipping of this area during northward but not southward migration by Namibia‐wintering sanderlings, all suggest they face issues during the late non‐breeding season in West Africa.Migrating sanderlings defy long distances but may end up in winter areas with poor fitness prospects. We suggest that ecological conditions in tropical West Africa make the fuelling prior to northward departure problematic. [ABSTRACT FROM AUTHOR]

Long‐distance migratory flights are predicted to be associated with higher mortality rates when individuals encounter adverse weather conditions. However, directly connecting environmental conditions experienced in‐flight with the survival of migrants has proven difficult. We studied how the in‐flight mortality of 53 satellite‐tagged Black‐tailed Godwits (Limosa limosa limosa) during 132 crossings of the Sahara Desert, a major geographical barrier along their migration route between The Netherlands and sub‐Saharan Africa, is correlated with the experienced wind conditions and departure date during both southward and northward migration. We show that godwits experienced higher wind assistance during southward crossings, which seems to reflect local prevailing trade winds. Critically, we found that fatal northward crossings (15 deaths during 61 crossings) were associated with adverse wind conditions. Wind conditions during migration can thus directly influence vital rates. Changing wind conditions associated with global change may thus profoundly influence the costs of long‐distance migration in the future. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Applied Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Identifying the factors shaping variation in parasite diversity among host species is crucial to understand wildlife diseases. Although micro‐ and macroparasites may exert different selective pressures on their hosts, studies investigating the determinants of parasite species richness in animals have rarely considered this divide.Here, we investigated the role of host life history and ecology in explaining the species richness of helminths (macroparasites) and haemosporidians (microparasites) in birds world‐wide. We collated data from multiple global datasets on diverse bird traits (longevity, body mass, coloniality, migration distance/tendency, geographic range size and dietary and habitat breadths) and the species richness of their helminth and haemosporidian parasites. We tested predictors of helminth and haemosporidian parasite richness using phylogenetic generalized linear mixed models in a Bayesian framework.We found that, after controlling for research effort and host phylogeny, the richness of helminths, but not of haemosporidians, increased with host longevity, range size, migration distance and dietary breadth. Overall, these correlates were also important across different helminth groups (acanthocephalans, cestodes, nematodes and trematodes), and two additional ones (body mass, coloniality) emerged as important for cestodes and acanthocephalans.We propose that long life spans may promote the diversity of helminth parasite assemblages over evolutionary time, thus resulting in richer helminth faunas. Similarly, longer‐distance migrations, larger ranges and broader dietary breadths are likely to lead to greater encounter rates and the accumulation of trophically transmitted helminths. In contrast, vector‐borne haemosporidians may be influenced more by factors related to vector ecology than by the host traits included in the analyses. The lack of strong associations between haemosporidian species richness and host characteristics emphasizes the need to find appropriate traits to model the distribution and diversity of parasites with different environmental preferences in order to anticipate disease emergence risks associated with global change. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Applied Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To successfully perform their long‐distance migrations, migratory birds require sites along their migratory routes to rest and refuel. Monitoring the use of so‐called stopover and staging sites provides insights into (a) the timing of migration and (b) the importance of a site for migratory bird populations. A recently developed Bayesian superpopulation model that integrates mark–recapture data and ring density data enabled the estimation of stopover timing, duration, and population size. Yet, this model did not account for heterogeneity in encounter (p) and staying (ϕ) probabilities.Here we extended the integrated superpopulation model by implementing finite mixtures to account for heterogeneity in p and ϕ. We used simulations and real data (from 2009–2016) on red knots Calidris canutus, mostly of the subspecies piersmai, staging in Bohai Bay, China, during spring migration to (a) show the importance of accounting for heterogeneity in encounter and staying probabilities to get unbiased estimates of stopover timing, duration, and numbers of migratory birds at staging sites and (b) get accurate stopover parameter estimates for a migratory bird species at a key staging site that is threatened by habitat destruction.Our simulations confirmed that heterogeneity in p affected stopover parameter estimates more than heterogeneity in ϕ, especially when most birds had low p. Bias was particularly severe when most birds had both low ϕ and p. Bias was largest for population size, intermediate for stopover duration and negligible for stopover timing.A total of 50,000–100,000 red knots were estimated to annually stop for 5–9 days in Bohai Bay between 10 and 30 May. This shows the key importance of this staging site for this declining species. There were no clear changes in stopover parameters over time, although stopover population size was substantially lower in 2016 than in preceding years.Our study shows the importance of accounting for heterogeneity in both encounter and staying probabilities for accurately estimating stopover duration and population size and provides an appropriate modeling framework. [ABSTRACT FROM AUTHOR]

Although the ecosystem engineering concept is well established in ecology, cases of joint engineering by multiple species at large scales remain rare. Here, we combine observational studies and exclosure experiments to investigate how co‐occurring greater flamingos Phoenicopterus roseus and fiddler crabs Uca tangeri promote their own and each other's food availability by creating a spatially complex mosaic of depressions (bowls, gullies) and hummocks (plateaus, mounds) in the intertidal zone. This results in a mosaic of microhabitats with different tidal inundation regimes. These microhabitats are spatially organized with labyrinth‐like patterns in the high intertidal zone and spotted patterns in the lower intertidal, both of which likely arise from biophysical interactions between these organisms and hydrodynamic forces. We show that the resulting spatial complexity is vital for biofilm production. The depression microhabitats were wetter and richer in organic matter and biofilms compared with hummocks. Excluding flamingos and crabs resulted in an increase in biofilm biomass over the shorter term (six months), but a decrease over the longer term (after one year). Moreover, our results strongly suggest that these biogeomorphological microhabitats in the mosaics were maintained by the feeding activities of flamingos and to a lesser extent crabs. During a period of flamingo exclusion, all the spotted patterns filled up with sediment, while the exclusion of crabs led to gradual sediment accumulation in the labyrinth‐like patterns. Collectively, these findings provide empirical evidence for large‐scale joint promotion of food availability by multiple taxa in a marine ecosystem. [ABSTRACT FROM AUTHOR]

Organisms cope with environmental stressors by behavioral, morphological, and physiological adjustments. Documentation of such adjustments in the wild provides information on the response space in nature and the extent to which behavioral and bodily adjustments lead to appropriate performance effects. Here we studied the morphological and digestive adjustments in a staging population of migrating Great Knots Calidris tenuirostris in response to stark declines in food abundance and quality at the Yalu Jiang estuarine wetland (northern Yellow Sea, China). At Yalu Jiang, from 2011 to 2017 the densities of intertidal mollusks, the food of Great Knots, declined 15‐fold. The staple prey of Great Knots shifted from the relatively soft‐shelled bivalve Potamocorbula laevis in 2011–2012 to harder‐shelled mollusks such as the gastropod Umbonium thomasi in 2016–2017. The crushing of the mollusks in the gizzard would require a threefold to 11‐fold increase in break force. This was partially resolved by a 15% increase in gizzard mass which would yield a 32% increase in shell processing capacity. The consumption of harder‐shelled mollusks was also accompanied by reliance on regurgitates to excrete unbreakable parts of prey, rather than the usual intestinal voidance of shell fragments as feces. Despite the changes in digestive morphology and strategy, there was still an 85% reduction in intake rate in 2016–2017 compared with 2011–2012. With these morphological and digestive adjustments, the Great Knots remaining faithful to the staging site to a certain extent buffered the disadvantageous effects of dramatic food declines. However, compensation was not complete. Locally, birds will have had to extend foraging time and use a greater daily foraging range. This study offers a perspective on how individual animals may mitigate the effects of environmental change by morphological and digestive strategies and the limits to the response space of long‐distance migrating shorebirds in the wild. [ABSTRACT FROM AUTHOR]

In seasonal environments, increasing spring temperatures lead many taxa to advance the timing of reproduction. Species that do not may suffer lower fitness. We investigated why black‐tailed godwits (Limosa limosa limosa), a ground‐breeding agricultural grassland shorebird, have not advanced timing of reproduction during the last three decades in the face of climate change and human‐induced habitat degradation. We used data from an 11‐year field study to parameterize an Integral Projection Model to predict how spring temperature and habitat quality simultaneously influence the timing of reproduction and population dynamics. We found apparent selection for earlier laying, but not a correlation between the laying dates of parents and their offspring. Nevertheless, in warmer springs, laying dates of adults show a stronger positive correlation with laying date in previous springs than in cooler ones, and this leads us to predict a slight advance in the timing of reproduction if spring temperatures continue to increase. We also show that only in landscapes with low agricultural activity, the population can continue to act as a source. This study shows how climate change and declining habitat quality may enhance extinction risk. Using long‐term field data of black‐tailed godwits, we modelled the combined effects of increasing spring temperature and declining habitat quality on laying dates and population dynamics. We examined how laying date affected fitness, and consequently population growth rates, and predicted how laying date would change over time. We found selection pressure for earlier laying, yet we predicted only a small advance in laying dates if spring temperatures continue to increase. We show that declining habitat quality amplifies negative effects of climate change: Only in the best‐quality habitats, we predicted no detrimental effects of spring warming on population growth rates. [ABSTRACT FROM AUTHOR]

Abstract: Life‐history responses to ecological selection pressures can be described by a slow–fast life‐history axis. Along this axis, fast‐living animals usually invest in high breeding output, whereas slow‐living ones prioritize their own survival. Birds may solve the trade‐off between reproduction and survival by optimizing their seasonal schedules. Breeding early tends to facilitate reproductive success, whereas breeding late increases the chances to survive. On the basis of this argument, short‐ and long‐lived birds should benefit from initiating spring activities earlier and later, respectively. The timing of seasonal activities, all else being equal, depends on the architecture of endogenous circannual clocks. Particularly, the length of the circannual period relative to the 365‐day environmental year either facilitates the anticipation of seasonal activities (in case of periods shorter than 365 days) or represents a responsive mode (when periods are longer than 365 days). The two alternatives will be manifested by early or late annual chronotypes, respectively. We hypothesize that in birds, annual chronotype will correspond with position on the “pace‐of‐life scale.” Species with low survival probability, and thus a poor chance of breeding in a next season, should show early annual chronotypes facilitated by circannual‐clock periods shorter than 365 days. In contrast, species with high survival rates should benefit from relatively long circannual periods. We predicted that circannual‐period lengths should correlate positively with species‐specific adult annual survival rates. Using published data for 16 wild bird species, we confirmed the predicted correlation. In our analysis, we accounted for the possible metabolic nature of circannual clocks, a correlation between rate of metabolism and survival, and phylogenetic relationships. On the basis of our finding, we propose that evolutionary responsive circannual clocks help birds cope with temporal variation in the environment in ways that are most appropriate for their life‐history and life‐table attributes. A plain language summary is available for this article. [ABSTRACT FROM AUTHOR]

GLO:K8N/01jan21:ibi12883-fig-0001.jpg PHOTO (COLOR): . gl Theunis Piersma's contribution to ornithology goes far beyond his 500 plus peer-reviewed scientific papers and 14 books, generally focused on migratory birds, to his role in their conservation including via innovative use of the arts as well as influencing policies and management prescriptions. For approaching four decades Theunis has been a mainstay of the International Wader Study Group (IWSG), serving 15 of those years as Vice-Chair. The strength and breadth of Theunis' work within ornithology makes him an outstandingly deserving recipient of the BOU Goldman Salvin Prize, and for it to be awarded during his beloved International Wader Study Group's 50th anniversary conference is a fitting and fine tribute to an exceptional ornithologist. [Extracted from the article]

Abstract: The increasing availability of high resolution and high frequency, radar‐based remote sensing data (i.e. observations on land surface characteristics, insensitive to cloud interference), makes it possible to track land‐use intensity more precisely at the whole landscape scale. Here, we develop a new radar‐based remote sensing technique for large‐scale quantification of agricultural land‐use intensity across human‐dominated landscapes. We compare the respective abilities of Sentinel‐1 C‐band radar (C‐SAR, C‐band synthetic aperture radar) remote sensing data with the more traditional optical data, as MODIS enhanced vegetation indices (MODIS EVI), in capturing seasonality and the magnitude of land‐use intensity (quantity and frequency of biomass removal). Linking our novel radar‐based change detection algorithm to agricultural management activities on the ground, we quantify a whole landscape according to timing of mowing, a key grassland disturbance, thus capturing the dynamics of mowing regimes in grasslands. We found that the radar‐based proxy provides a rapid and reliable measure of land‐use intensity, reliably predicting plant community composition at the landscape scale. We tested this methodology using data on black‐tailed godwits (Limosa limosa limosa), a specialist breeder of lowland meadows which, over the last 50 years, has shown dramatic declines. During territory establishment, black‐tailed godwits preferentially used fields corresponding to intermediate radar‐sensed land‐use intensities. However, the present‐day timing of mowing in these habitats was such that most godwit broods were less likely to be successful than broods in grasslands used at a lower intensity. Synthesis and applications. The newly developed radar‐based land‐use intensity quantification is a powerful tool that makes it possible for ecologists and land managers to include agricultural land‐use intensity measurements in population studies of the plants, insects, birds and mammals using these landscapes, at the spatial scale of entire populations. Applications of this tool include evaluating the effectiveness of European agri‐environment schemes aiming to increase biodiversity through decreased land‐use intensity or expanding the quantification of agricultural land‐use intensity to other geographic regions. [ABSTRACT FROM AUTHOR]

Rock Sandpipers Calidris ptilocnemis have the most northerly non‐breeding distribution of any shorebird in the Pacific Basin (upper Cook Inlet, Alaska; 61°N, 151°W). In terms of freezing temperatures, persistent winds and pervasive ice, this site is the harshest used by shorebirds during winter. We integrated physiological, metabolic, behavioural and environmental aspects of the non‐breeding ecology of Rock Sandpipers at the northern extent of their range to determine the relative importance of these factors in facilitating their unique non‐breeding ecology. Not surprisingly, estimated daily energetic demands were greatest during January, the coldest period of winter. These estimates were greatest for foraging birds, and exceeded basal metabolic rates by a factor of 6.5, a scope of increase that approaches the maximum sustained rate of energetic output by shorebirds during periods of migration, but far exceeds these periods in duration. We assessed the quality of their primary prey, the bivalve Macoma balthica, to determine the daily foraging duration required by Rock Sandpipers to satisfy such energetic demands. Based on size‐specific estimates of M. balthica quality, Rock Sandpipers require over 13 h/day of foraging time in upper Cook Inlet in January, even when feeding on the highest quality prey. This range approaches the average daily duration of mudflat availability in this region (c. 18 h), a maximum value that annually decreases due to the accumulation of shore‐fast ice. Rock Sandpipers are likely to maximize access to foraging sites by following the exposure of ice‐free mudflats across the upper Cook Inlet region and by selecting smaller, higher quality M. balthica to minimize foraging times. Ultimately, this unusual non‐breeding ecology relies on the high quality of their prey resources. Compared with other sites across their range, M. balthica from upper Cook Inlet have relatively light shells, potentially the result of the region's depauperate invertebrate predator community. Given the delicate balance between environmental and prey conditions that currently make Cook Inlet a viable wintering area for Rock Sandpipers, small variations in these variables may affect the suitability of the site in the future. [ABSTRACT FROM AUTHOR]

Abstract: Aim: Molluscivorous shorebirds supposedly developed their present wintering distribution after the last ice age. Currently, molluscivorous shorebirds are abundant on almost all shores of the world, except for those in the Indo‐West Pacific (IWP). Long before shorebirds arrived on the scene, molluscan prey in the IWP evolved strong anti‐predation traits in a prolonged evolutionary arms race with durophagous predators including brachyuran crabs. Here, we investigate whether the absence of molluscivorous shorebirds from a site in Oman can be explained by the molluscan community being too well‐defended. Location: The intertidal mudflats of Barr Al Hikman, Oman. Methods: Based on samples from 282 locations across the intertidal area the standing stock of the macrozoobenthic community was investigated. By measuring anti‐predation traits (burrowing depth, size and strength of armour), the fraction of molluscs available to molluscivorous shorebirds was calculated. Results: Molluscs dominated the macrozoobenthic community at Barr Al Hikman. However, less than 17% of the total molluscan biomass was available to shorebirds. Most molluscs were unavailable either because of their hard‐to‐crush shells, or because they lived too deeply in the sediment. Repair scars and direct observations confirmed crab predation on molluscs. Although standing stock densities of the Barr Al Hikman molluscs were of the same order of magnitude as at intertidal mudflat areas where molluscivorous shorebirds are abundant, the molluscan biomass available to shorebirds was distinctly lower at Barr Al Hikman. Main conclusions: The established strong molluscan anti‐predation traits against crabs precludes molluscan exploitation by shorebirds at Barr Al Hikman. This study exemplifies that dispersal of “novel” predators is hampered in areas where native predators and prey exhibit strongly developed attack and defence mechanisms, and highlights that evolutionary arms races can have consequences for the global distribution of species. [ABSTRACT FROM AUTHOR]

Sexual size dimorphism ( SSD) is common in birds and has been linked to various selective forces. Nevertheless, the question of how and when the sexes start to differentiate from each other is poorly studied. This is a critical knowledge gap, as sex differences in growth may cause different responses to similar ecological conditions. In this study, we describe the sex-specific growth - based on body mass and five morphometric measurements - of 56 captive Black-tailed Godwit Limosa limosa limosa chicks raised under ad libitum food conditions, and conclude that all six growth curves are sex-specific. Females are the larger sex in terms of body mass and skeletal body size. To test whether sex-specific growth leads to sex-specific susceptibility to environmental conditions, we compared the age-specific sizes of male and female chicks in the wild with those of Black-tailed Godwits reared in captivity. We then tested for a relationship between residual growth and relative hatching date, age, sex and habitat type in which the wild chicks were born. Early-hatched chicks were relatively bigger and in better condition than late-hatched chicks, but body condition and size were not affected by natal habitat type. Female chicks deviated more negatively from the sex-specific growth curves than male chicks for body mass and total-head length. This suggests that the growth of the larger females is more susceptible to limiting environmental conditions. On average, the deviations of wild chicks from the predicted growth curves were negative for all measurements, which suggests that conditions are limiting in the current agricultural landscape. We argue that in estimating growth curves for sexually dimorphic species, it is critical first to make accurate sex and age determinations. [ABSTRACT FROM AUTHOR]

Solar geolocators are relatively cheap and simple tools which are widely used to study the migration of animals, especially birds. The methods to estimate the geographic positions from the light-intensity patterns collected by these loggers, however, are still under development., The accurate reconstruction of the annual schedules and movement patterns of individual animals requires analytical methods which provide estimates of daily locations, distances between the locations and the directions of movement, with measures of their uncertainty., The new r package FL ightR meets all these requirements. It enables refined and statistically validated estimations of movement patterns of birds. Here, we present main features of this advanced package. [ABSTRACT FROM AUTHOR]

1. Migration is a widespread phenomenon in the animal kingdom. On the basis of the considerable variation that exists between and within species and even within populations, we may be able to infer the (age and sex-specific) ecological trade-offs and constraints moulding migration systems from assessments of fitness associated with migration and wintering in different areas. 2. During three consecutive breeding seasons, we compared the reproductive performance (timing of breeding, breeding success, chick body condition and post-fledging survival) of Eurasian spoonbills Platalea leucorodia that breed at a single breeding site in The Netherlands, but migrate different distances (c. 4,500 vs. 2,000 km, either or not crossing the Sahara) to and from wintering areas in southern Europe and West Africa. Using mark-recapture analysis, we further investigated whether survival until adulthood (recruitment probability) of chicks hatched between 2006 and 2010 was related to their hatch date and body condition. 3. Long-distance migrants bred later, particularly the males and raised chicks of poorer body condition than short-distance migrants. Hatch dates strongly advanced with increasing age in short-distance migrants, but hardly advanced in longdistance migrants, causing the difference in timing of breeding between long and short-distance migrants to be more pronounced among older birds. 4. Breeding success and chick body condition decreased over the season and chicks that fledged late in the season or in poor condition were less likely to survive until adulthood. As a result, long-distance migrants--particularly the males and older birds--likely recruit fewer offspring into the breeding population than short-distance migrants. This inference is important for predicting the population-level consequences of changes in winter habitat suitability throughout the wintering range. 5. Assuming that the long-distance migrants--being the birds that occupy the traditional wintering areas--are not the poorer quality birds and that the observed agedependent patterns in timing of breeding are driven by within-individual effects and not by selective disappearance, our results suggest that the strategy of long-distance migration, involving the crossing of the Sahara to winter in West Africa, incurred a cost by reducing reproductive output, albeit a cost paid only later in life. [ABSTRACT FROM AUTHOR]

Ruff Philomachus pugnax staging in the Netherlands forage in agricultural grasslands, where they mainly eat earthworms (Lumbricidae). Food intake and the surface availability of earthworms were studied in dairy farmland of southwest Friesland in March-April 2011. Daily changes in earthworm availability were quantified by counting visible earthworms. No earthworms were seen on the surface during daytime, but their numbers sharply increased after sunset and remained high during the night. Nevertheless, intake rates of individual Ruff in different grasslands measured during daytime showed the typical Holling type II functional response relationship with the surfacing earthworm densities measured at night. Radiotagging of Ruff in spring 2007 revealed that most, if not all, feeding occurs during the day, with the Ruff assembling at shoreline roosts at night. This raises the question of why Ruff do not feed at night, if prey can be caught more easily than during daytime. In March-May 2013 we experimentally examined the visual and auditory sensory modalities used by Ruff to find and capture earthworms. Five males were kept in an indoor aviary and we recorded them individually foraging on trays with 10 earthworms mixed with soil under various standardized light and white noise conditions. The number of earthworms discovered and eaten by Ruff increased with light level, but only when white noise was played, suggesting that although they can detect earthworms by sight, Ruff also use auditory cues. We suggest that although surfacing numbers of earthworms are highest during the night, diurnal intake rates are probably sufficient to avoid nocturnal foraging on a resource that is more available but perhaps less detectable at that time. [ABSTRACT FROM AUTHOR]

Aim Habitat use and migration strategies of animals are often associated with spatial variation in parasite pressure, but how they relate to one another is not well understood. Here, we use a large dataset on helminth species richness of Charadriiform birds to test whether higher habitat diversity and seasonal migration increase parasite richness in avian hosts. Location Global. Methods We compiled a global dataset on helminth species richness, habitat use strategies (marine/freshwater/mixed wintering and osmotic generalist/specialist) and various ecological/life-history traits (migration distance, geographical range size, diet, body mass, sampling latitude) of Charadriiform birds. To test if hosts with different habitat use strategies encounter different parasite pressures, we used comparative methods that correct for shared ancestry and phylogenetic uncertainty. Results Habitat generalists (mixed wintering habitats and osmotic generalists) harboured more parasite species than habitat specialists; marine- and freshwater-restricted hosts had similar helminth species richness. Contrary to previous results, we found no association between parasite species richness and migration distance. Overall helminth species richness also increased with diet diversity, with no effects of other ecological/life-history traits. Main conclusions We suggest that birds exploiting diverse habitats and diets are exposed to a more diverse parasite fauna and conclude that distribution patterns and habitat use, rather than migration distance, shape parasite diversity within host populations. Overall, these results demonstrate the significant role of habitat use in explaining how migration may indirectly affect parasite richness in host populations. [ABSTRACT FROM AUTHOR]

Animals frequently exhibit consistent among-individual differences in behavioural and physiological traits that are inherently flexible. Why should individuals differ consistently in their expression of labile traits? Recently, positive feedbacks between state and behaviour have been proposed as a possible explanation for the maintenance of consistent among-individual differences in both state and behaviour. If state affects behaviour, and behaviour reciprocally affects state, then differences in either state or behaviour that arise among individuals even by chance could be maintained over extended periods of time., We tested for positive feedbacks experimentally using wild-caught red knots ( Calidris canutus islandica). In the wild, knots exhibit consistent among-individual differences in digestive physiology (the mass of the muscular part of the stomach, the gizzard) and foraging behaviour (diet), two inherently labile traits., Experimentally manipulated diet quality had a large effect on gizzard mass. Experimentally manipulated gizzard mass reciprocally influenced total food eaten during ad libitum trials., The effect of gizzard mass on diet choice, though in the predicted direction, was not statistically significant. Individuals exhibited consistent differences in foraging behaviour of unknown origin independent of current gizzard mass, as well as large residual unexplained variance in foraging behaviour. These two sources of variation in foraging behaviour overruled the gizzard mass-dependent foraging behaviour and hence eroded the treatment-related differences in gizzard mass., We conclude that positive feedbacks between diet choice and gizzard mass play at best a limited role in maintaining among-individual variation in gizzard mass in red knots. Furthermore, we suggest that many models of state-behaviour feedbacks likely overestimate their potential importance in maintaining long-term among-individual variation in labile traits because most models of state-behaviour feedbacks fail to account for the effects of additional factors that may act to disrupt the feedback loops., The among-individual differences in diet choice observed during solitary foraging trials eroded the consistent among-individual differences in gizzard mass observed following periods of staple diet treatments in which knots foraged in social groups. Social foraging interactions may play an important role determining the expression of foraging behaviours such as intake rate that in turn influence gizzard mass. Further studies are needed to experimentally test the role of social interactions as a mechanism generating consistent among-individual differences in foraging behaviours and gizzard mass., A is available for this article. [ABSTRACT FROM AUTHOR]