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Many animals migrate long distances annually, and these journeys require intense physiological and morphological adaptations. One such adaptation in shorebirds is the ability to rapidly gain weight at stopover locations in the middle of their migrations. Shorebirds migrate long distances twice annually, which requires intense physiological and morphological adaptations, including the ability to rapidly gain weight via fat deposition at stopover locations. The role of the microbiome in weight gain in avian hosts is unresolved, but there is substantial evidence to support the hypothesis that the microbiome is involved with host weight from mammalian microbiome literature. Here, we collected 100 fecal samples of Ruddy Turnstones to investigate microbiome composition and function during stopover weight gain in Delaware Bay, USA. Using 16S rRNA sequencing on 90 of these samples and metatranscriptomic sequencing on 22, we show that taxonomic composition of the microbiome shifts during weight gain, as do functional aspects of the metatranscriptome. We identified 10 genes that are associated with weight class, and polyunsaturated fatty acid biosynthesis in the microbiota is significantly increasing as birds gain weight. Our results support that the microbiome is a dynamic feature of host biology that interacts with both the host and the environment and may be involved in the rapid weight gain of shorebirds. IMPORTANCE Many animals migrate long distances annually, and these journeys require intense physiological and morphological adaptations. One such adaptation in shorebirds is the ability to rapidly gain weight at stopover locations in the middle of their migrations. The role of the microbiome in weight gain in birds is unresolved but is likely to play a role. Here, we collected 100 fecal samples from Ruddy Turnstones to investigate microbiome composition (who is there) and function (what they are doing) during stopover weight gain in Delaware Bay, USA. Using multiple molecular methods, we show that both taxonomic composition and function of the microbiome shifts during weight gain. We identified 10 genes that are associated with weight class, and polyunsaturated fatty acid biosynthesis in the microbiota is significantly increasing as birds gain weight. Our results support that the microbiome is a dynamic feature of host biology that interacts with both the host and the environment and may be involved in the rapid weight gain of shorebirds.

Since 1985, avian influenza virus surveillance has been conducted annually from mid-May to early June in charadriiform species from the families Scolopacidae and Laridae (shorebirds and gulls) at Delaware Bay in the northeast United States. The mass migrations of shorebirds, gulls and horseshoe crabs (Limulus polyphemus) coincide at that time, and large numbers of migrating birds pause at Delaware Bay to feed on horseshoe crab eggs deposited at the high-tide line. Influenza viruses are consistently isolated from charadriiform birds at Delaware Bay, at an overall rate approximately 17 times the combined rate of isolation at all other surveillance sites worldwide (490 isolates/9474 samples, 5.2% versus 49 isolates per 15 848 samples, 0.3%, respectively; Proportion test, p < 0.0001). The likelihood of isolating influenza viruses at Delaware Bay is dependent on the presence of ruddy turnstone (Arenaria interpres) at the sampling site (G-test of independence, p < 0.001). The convergence of host factors and environmental factors results in a unique ecological ‘hot spot’ for influenza viruses in Charadriiformes.

Each May for over three decades, avian influenza A viruses (IAVs) have been isolated from shorebirds and gulls (order Charadriiformes) at Delaware Bay (DE Bay), USA, which is a critical stopover site for shorebirds on their spring migration to arctic breeding grounds. At DE Bay, most isolates have been recovered from ruddy turnstones (Arenaria interpres), but it is unknown if this species is involved in either the maintenance or movement of these viruses outside of this site. We collected and tested fecal samples from 2823 ruddy turnstones in Florida and Georgia in the southeastern United States during four winter/spring sample periods—2010, 2011, 2012, and 2013—and during the winters of 2014/2015 and 2015/2016. Twenty-five low pathogenicity IAVs were recovered representing five subtypes (H3N4, H3N8, H5N9, H6N1, and H12N2). Many of these subtypes matched those recovered at DE Bay during the previous year or that year’s migratory cycle, suggesting that IAVs present on these southern wintering areas represent a source of virus introduction to DE Bay via migrating ruddy turnstones. Analyses of all IAV gene segments of H5N9 and H6N1 viruses recovered from ruddy turnstones at DE Bay during May 2012 and from the southeast during the spring of 2012 revealed a high level of genetic relatedness at the nucleotide level, suggesting that migrating ruddy turnstones move IAVs from wintering grounds to the DE Bay ecosystem.

1. Migration counts are popular indices used to monitor population trends over time. Advanced analytical methods for estimating abundance of unmarked, open populations now incorporate population growth models and simultaneously test for covariate effects on abundance and detection probability. However, estimating population abundance at a staging site is complicated by daily immigration and emigration of unmarked individuals. 2. We applied a set of generalized N-mixture models to simulated count data to test their applicability for transient populations. Using simulated datasets, parameters were unbiased when the apparent survival rate varied within a season or was misspecified in a model, but not when the immigration or detection probability was mis-specified. 3. With knowledge from the simulated data, we applied these models to daily counts of staging migratory shorebirds and estimated daily abundances accounting for variation in the detection and immigration rates. Daily counts of ruddy turnstones (Arenaria interpres) staging at Westhampton Island, New York, were collected during northward migration (1997-1999). We tested the effects of weather and tides on detection probability, and we modelled within-season variation in immigration rates as a function of time. 4. Covariates affecting the detection probability differed among years, but tide height consistently was correlated with detection probability. Accounting for detection and immigration rates, the predicted maximum single-day populations of ruddy turnstones were 172%, 165% and 129% of the observed counts for each year. 5. Synthesis and applications. Management and conservation plans for migratory species require abundance estimates that are near the true population size though they are difficult to obtain. Our study is the first empirical application of the generalized N-mixture model that incorporates temporal trends in immigration and estimates daily abundance of a staging unmarked migratory population. Despite its inherent limitation, we suggest that the generalized N-mixture model can estimate the abundance of transient populations with low individual heterogeneity when counts are intensively surveyed. Correct estimation of population sizes and the environmental factors affecting them can aid the conservation prioritization of species and staging sites. Moreover, the use of generalized N-mixture models can improve our understanding of the environmental factors that shape migratory movements.

Migratory birds make decisions about how far to travel based on cost-benefit trade-offs. However, in many cases the net effect of these trade-offs is unclear. We sought to address this question by measuring feather corticosterone (CORTf), leucocyte profile, avian malaria parasite prevalence and estimating fueling rates in three spatially segregated wintering populations of the migratory shorebird ruddy turnstone Arenaria interpres during their stay in the winter habitat. These birds fly from the high-Arctic breeding ground to Australia, but differ in that some decide to end their migration early (Broome, Western Australia), whereas others travel further to either South Australia or Tasmania. We hypothesized that the extra costs in birds migrating greater distances and overwintering in colder climates would be offset by benefits when reaching their destination. This would be evidenced by lower stress biomarkers in populations that travel further, owing to the expected benefits of greater resources and improved vitality. We show that avian malaria prevalence and physiological stress levels were lower in birds flying to South Australia and Tasmania than those overwintering in Broome. Furthermore, our modeling predicts that birds in the southernmost locations enjoy higher fueling rates. Our data are consistent with the interpretation that birds occupying more costly wintering locations in terms of higher migratory flight and thermoregulatory costs are compensated by better feeding conditions and lower blood parasite infections, which facilitates timely and speedy migration back to the breeding ground. These data contribute to our understanding of cost-benefit trade-offs in the decision making underlying migratory behaviour.

The results of a comparison of the long-term population dynamics of seabirds breeding in the western part of the White Sea on both protected and unprotected islands are presented. A series of observations was conducted for more than 50 years in the Kandalaksha Nature Reserve and for more than 30 years in the Solovetskii Archipelago. The dynamics of the breeding part of the population were analyzed for six species occurring in both study areas. The population trends of the common eider Somateria mollissima , the European herring gull Larus argentatus , and the black guillemot Cepphus grylle , were the same in the two areas, while those of the Eurasian oystercatcher Haematopus ostralegus , the common gull Larus canus , and the ruddy turnstone Arenaria interpres differed. The uniform trends are due to similar natural conditions of the breeding and wintering grounds of the birds in the Solovetskii Archipelago and Kandalaksha Bay. The discrepancies are mostly associated with different protection regimes on the islands used for breeding, as well as with an increased pressure of both terrestrial and avian predators on seabird colonies in recent decades.

What draws us to the beauty of a peacock, the flight of an eagle, or the song of a nightingale? Why are birds so significant in our lives and our sense of the world? And what do our ways of thinking about and experiencing birds tell us about ourselves? Birdscapes is a unique meditation on the variety of human responses to birds, from antiquity to today, and from casual observers to the globe-trotting \"twitchers\" who sometimes risk life, limb, and marriages simply to add new species to their \"life lists.\" Drawing extensively on literature, history, philosophy, and science, Jeremy Mynott puts his own experiences as a birdwatcher in a rich cultural context. His sources range from the familiar--Thoreau, Keats, Darwin, and Audubon--to the unexpected--Benjamin Franklin, Giacomo Puccini, Oscar Wilde, and Monty Python. Just as unusual are the extensive illustrations, which explore our perceptions and representations of birds through images such as national emblems, women's hats, professional sports logos, and a Christmas biscuit tin, as well as classics of bird art. Each chapter takes up a new theme--from rarity, beauty, and sound to conservation, naming, and symbolism--and is set in a new place, as Mynott travels from his \"home patch\" in Suffolk, England, to his \"away patch\" in New York City's Central Park, as well as to Russia, Australia, and Greece. Conversational, playful, and witty, Birdscapes gently leads us to reflect on large questions about our relation to birds and the natural world. It encourages birders to see their pursuits in a broader human context--and it shows nonbirders what they may be missing.

Conservation is increasingly in conflict with human activities due to global human population growth, particularly in areas that support threatened species. Conflicts often impede effective implementation of needed conservation measures and also have implications for social inequality, resource use and economic development. Bivalve molluscan shellfish aquaculture is commonly considered one of the least impactful forms of protein production worldwide but, in some locations, may interfere with essential activities of threatened species such as the stopover ecology of migrating shorebirds. Here we assess the impact of oyster aquaculture as practiced in Delaware Bay (New Jersey, USA) on the presence and foraging behavior of migratory shorebird species of conservation concern. We conducted counts and behavioral observations of shorebirds across a 4.8‐km stretch of the Delaware Bay and tested the effect of regulated aquaculture structures and activities on shorebird presence relative to various environmental factors. We also evaluated differences in mean peck rates for each species within and away from aquaculture areas, and we examined multiple factors influencing foraging rates for each species. For all species, we found that oyster tending reduced the probability of shorebird presence by 1–7%, whereas the untended aquaculture structures had no detectable impact. Foraging rates were mostly influenced by environmental conditions, particularly the presence of competitors (gulls or other shorebirds), and the foraging substrate. None of the focal species substantially altered their time budget or foraging rates in the presence of tended or untended oyster aquaculture. This evidence suggests that intertidal oyster aquaculture and migrating shorebirds can co‐utilize the resource rich intertidal areas on which they occur.

The identity of two birds described from Paraguay by Félix de Azara as No. 378 “Ypacahá jaspeado encima” and No. 402 “Chorlito pies roxos” is elucidated for the first time. No. 378 refers to Ocellated Crake Micropygia schomburgkii and is the basis for the name Rallus maculosus of Vieillot, 1819. Rallus maculosus Vieillot, 1819, is a nomen oblitum, unavailable for application. No. 402 is referable to Ruddy Turnstone Arenaria interpres morinella and is the basis of the name Totanus nigellus Vieillot, 1816. Totanus nigellus Vieillot, 1816 is thus a junior synonym of Arenaria interpres morinella (Linnaeus, 1766) and available for application.