Search

Colonies of ground-nesting species often have heterogeneous nest densities and their offspring experience different social conditions depending on the size and location of the breeding territory. For example, unintentional territory crossing by mobile chicks can trigger strong aggression from neighbouring adults, as observed in semi-precocial gulls. This would be expected to shape chicks’ movement tendencies, exploratory behaviour and propensity for social contact through aversive feedback learning or pre-natal maternal effects, as mothers may pre-adapt their offspring’s behaviour to the expected early life conditions. Therefore, we hypothesize that lesser black-backed gull chicks reared in denser areas of the breeding colony will move less, have smaller home ranges and have fewer social contacts with chicks from neighbouring nests. To test this, we first cross-fostered full clutches between and within high- and low-density parts of the colony, and then used ultra-wideband tags to track free-ranging chicks. In line with our predictions, we found that chicks reared in denser areas had a lower movement activity and smaller home ranges. However, these chicks still had more social contacts, although not necessarily with a higher number of unique individuals. Pre-natal breeding density had no significant effect on any of the parameters. We conclude that parental nest choice strongly affects the early social environment of their chicks, which can shape the development of their (social) phenotype, with potentially long-lasting consequences.

Haemoproteus spp. are dipteran-borne protozoa that infect erythrocytes and reticulo-endothelial cells of birds. These parasites are not usually transmitted between birds belonging to different orders. The suborder Lari (order Charadriiformes) comprises ~170 avian species, the majority of which are aquatic, including gulls, terns, auklets, murres and skuas, among others. In spite of the diversity of this avian group, there is limited known diversity of haemosporidian parasites, with only 4 recorded Haemoproteus morphospecies thus far. We examined the blood smears of 21 kelp gulls (Larus dominicanus) captured at a breeding colony in South Africa, as well as Haemoproteus-positive archival blood smears of 15 kelp gulls and 1 Hartlaub's gull (Larus hartlaubii) sampled while under care at seabird rehabilitation facilities in South Africa. Haemoproteus sp. infection was detected in 19% of wild-caught kelp gulls. All parasites from the gulls were morphologically identified as Haemoproteus jenniae, a species previously recorded in Lari birds at the Galapagos Islands (Ecuador), Rocas Atoll (Brazil) and Poland. Gene sequencing uncovered a new cytochrome b lineage, LARDOM01, which was closely related to the previously reported H. jenniae lineage CREFUR01. Additionally, we evaluated a hapantotype blood smear of Haemoproteus skuae, which had been described infecting a brown skua (Catharacta antarctica) in South Africa. We provide a redescription of H. skuae and discuss the morphological characters distinguishing it from H. jenniae. Further research is necessary to improve our knowledge about the host and geographic distribution, health effects and phylogeny of H. jenniae and H. skuae.

Anthropogenic activities and the demand for trace elements have risen, causing an increase in their environmental levels, which could affect biota. High levels of trace elements in living beings have been associated with toxicity, metabolic disorders, oxidative stress, and cancer. Seabirds, such as gulls, have been used as bioindicators of environmental pollution caused by anthropogenic sources. Gulls are widely distributed worldwide, usually occupying high trophic levels, and living close to humans. Among gulls, Larus spp. are omnivorous, predominantly carnivorous, nest on the ground, and capture live food or steal it opportunistically. The present work summarizes the data of trace elements found in eggs, feathers, blood, and feces, among other internal tissues, of several gull species of the genus Larus around the world. Most of the reports are from the Northern Hemisphere (70%), particularly from Europe and North America. The elements Cd, Hg, Mn, Pb, and Se are the most studied (54%), among which Hg represents about 19%. On the other hand, there is no information for lesser-known trace elements such as Rb, Ti, new technology elements (e.g. Ge, Re, Ta), rare earth elements (e.g. Ce, La, Y), or elements of the platinum group (e.g. Os, Ir, Ru). Even though Larus spp. is a suitable bioindicator of chemical contamination in marine ecosystems, only 28 of the 53 species of the Larus genus have been used on trace elements pollution. Future research should address lesser-known elements which are increasingly used by new technologies. [ABSTRACT FROM AUTHOR]

Demographic rates such as recruitment and survival probability can vary considerably among populations of the same species due to variation in underlying environmental processes. If environmental processes are spatially correlated, nearby populations are expected to have more similar demographic rates than those further apart. Breeding populations and foraging ranges are spatially segregated in colonial seabirds, making them ideal for studying spatial patterns in demographic rates and their effects on local population dynamics. Here we explored variation in age‐dependent survival probabilities across 14 colonies of Herring Gulls Larus argentatus breeding along the Dutch North Sea coast. We used long‐term mark–recapture data of marked fledglings to estimate survival, and estimated spatial autocorrelation of survival probabilities. We assessed whether survival until recruitment age or until 10 years old (close to their expected lifespan) explained variation in population trajectories of each colony. Juvenile and adult survival showed a strong, but different, north‐to‐south gradient in survival probability, with lower juvenile but higher adult survival in northern colonies than southern colonies, whereas the spatial pattern of immature survival was less distinct. Neither recruitment nor the proportion of 10‐year‐old adults alive predicted whether a colony collapsed, declined, remained stable or increased. The distinct spatial pattern in survival suggests variation in regional food availability, which do not seem to drive local population dynamics. The absence of a link between survival and colony trajectories implies that connectivity between populations plays an important role affecting population dynamics. [ABSTRACT FROM AUTHOR]

Wild animal species living in anthropogenic areas are commonly carriers of antimicrobial‐resistant bacteria (AMRB), but their role in the epidemiology of these bacteria is unclear. Several studies on AMRB in wildlife have been cross‐sectional in design and sampled individual animals at only one point in time. To further understand the role of wildlife in maintaining and potentially transmitting these bacteria to humans and livestock, longitudinal studies are needed in which samples are collected from individual animals over multiple time periods. In Europe, free‐ranging yellow‐legged gulls (Larus michahellis) commonly live in industrialized areas, forage in landfills, and have been found to carry AMRB in their feces. Using bacterial metagenomics and antimicrobial resistance characterization, we investigated the spatial and temporal patterns of AMRB in a nesting colony of yellow‐legged gulls from an industrialized area in southern France. We collected 54 cloacal swabs from 31 yellow‐legged gull chicks in 20 nests on three dates in 2016. We found that AMRB in chicks increased over time and was not spatially structured within the gull colony. This study highlights the complex occurrence of AMRB in a free‐ranging wildlife species and contributes to our understanding of the public health risks and implications associated with ARMB‐carrying gulls living in anthropogenic areas. [ABSTRACT FROM AUTHOR]

Abstract Wild animal species living in anthropogenic areas are commonly carriers of antimicrobial‐resistant bacteria (AMRB), but their role in the epidemiology of these bacteria is unclear. Several studies on AMRB in wildlife have been cross‐sectional in design and sampled individual animals at only one point in time. To further understand the role of wildlife in maintaining and potentially transmitting these bacteria to humans and livestock, longitudinal studies are needed in which samples are collected from individual animals over multiple time periods. In Europe, free‐ranging yellow‐legged gulls (Larus michahellis) commonly live in industrialized areas, forage in landfills, and have been found to carry AMRB in their feces. Using bacterial metagenomics and antimicrobial resistance characterization, we investigated the spatial and temporal patterns of AMRB in a nesting colony of yellow‐legged gulls from an industrialized area in southern France. We collected 54 cloacal swabs from 31 yellow‐legged gull chicks in 20 nests on three dates in 2016. We found that AMRB in chicks increased over time and was not spatially structured within the gull colony. This study highlights the complex occurrence of AMRB in a free‐ranging wildlife species and contributes to our understanding of the public health risks and implications associated with ARMB‐carrying gulls living in anthropogenic areas.

Distribution of sibling species Larus cachinnans (Pallas, 1811) and Larus michahellis (J. F. Naumann 1840) were studied on coast of the Black Sea. Originally, Larus michahellis breeds on seaside cliffs and rocky islets of the Southern part of the Black Sea and of the Crimean Peninsula. Having adapted to breeding on the roofs of buildings, this species is spread to the north along the seaside: to Novorossiysk on the eastern coast, to Constanta on the western one. Additionally, an isolated population of Larus cachinnans breeds on low-lying islands and sand spits mostly in the Northwestern Black Sea. Here, the species spreads on the seaside from Constanta northward to Karkinitian Bay. Further to the east, breeding populations of Caspian Gull are found on the Black Sea coast only at the southeastern edge of the Taman Peninsula to the south to Anapa. The coast of the Sea of Azov, adjacent to the northeastern part of the Black Sea, is densely populated by Larus cachinnans. Only in the southern part of the Sea of Azov, on the coast of the Kerch Peninsula, there is a small population of Larus michahellis. [ABSTRACT FROM AUTHOR]

Seabirds breeding in the high Arctic contend with variable annual sea ice conditions, with important consequences depending on a species' unique reproductive and foraging ecology. We assessed the influence of sea ice extent and phenology on seabird breeding biology using monitoring data collected for northern fulmar (Fulmarus glacialis), glaucous gull (Larus hyperboreus), black-legged kittiwake (Rissa tridactyla), and thick-billed murre (Uria lomvia) breeding at Prince Leopold Island, Nunavut, Canada over 4 decades. We expected that years of later sea ice break-up and greater ice cover around the colony would create greater challenges to foraging and could result in delayed nest initiation, decreased colony attendance, and lower nesting success, but with distinct responses from each species. We also tested for time-lagged effects of ice conditions, where sea ice in a given year could impact food availability or juvenile recruitment in later years. Ice conditions around the colony exhibited no significant overall temporal trends or changepoints over the past 50 years (1970–2021), while counts of kittiwakes and murres increased over the study period 1975–2013. No trends were evident in counts of fulmars or gulls or in egg-laying dates or nest success for any species. However, three species (all but glaucous gulls) exhibited unique responses between breeding metrics and sea ice, highlighting how breeding decisions and outcomes may differ among species under the same environmental conditions in a given year. Time-lagged effects were only detected for kittiwake nest counts, where the date of spring ice break-up around the colony was negatively associated with counts at a 5-year lag. Greater distances to open water were associated with lower colony attendance by fulmars and later nest initiation by kittiwakes and murres. Our analyses provide additional insights to effects of sea ice on high-Arctic seabird breeding ecology, which will be useful in predicting and planning for the complex effects of a changing climate and changing human pressures on this high-latitude ecosystem and for the management of high-Arctic marine-protected areas. [ABSTRACT FROM AUTHOR]

The feeding ecology and behavior of breeding Iceland Gulls Larus glaucoides kumlieni and, to a lesser extent, American Herring Gulls Larus smithsonianus and Glaucous Gulls Larus hyperboreus, were studied at a large Iceland Gull colony located near Kinngait, Baffin Island, Canada. Iceland Gulls collected food close to the colony, mainly at ebbing and low tides, on or very close to the shoreline, and in adjacent nearshore waters. The most common feeding technique was picking on the water surface while swimming. Additional techniques included plunging to capture food items at greater depths and kleptoparasitism. Known food items included marine invertebrates and small fish. American Herring and Glaucous gulls nested in the study area in substantially lower numbers than Iceland Gulls but used similar feeding habitats and techniques and collected similar food items. The specific feeding techniques used by all three species were typical of many large Larus gulls. Sufficient food availability at the time of the study may explain some of the observed similarities in feeding habitat use and behavior. An important component of broad niche separation for Iceland Gulls in areas of sympatry may be sea-cliff nesting and concentrated use of coastal marine habitats for feeding, including shorelines and nearshore areas. In addition, other studies have shown that American Herring and Glaucous gulls use more inland and terrestrial habitats, use more diverse foods, and employ different feeding behaviors, including more predation and scavenging. Additional studies in selected areas are needed to fully address the questions raised in this study. [ABSTRACT FROM AUTHOR]

Colonies of ground-nesting species often have heterogeneous nest densities and their offspring experience different social conditions depending on the size and location of the breeding territory. For example, unintentional territory crossing by mobile chicks can trigger strong aggression from neighbouring adults, as observed in semi-precocial gulls. This would be expected to shape chicks' movement tendencies, exploratory behaviour and propensity for social contact through aversive feedback learning or pre-natal maternal effects, as mothers may pre-adapt their offspring's behaviour to the expected early life conditions. Therefore, we hypothesize that lesser black-backed gull chicks reared in denser areas of the breeding colony will move less, have smaller home ranges and have fewer social contacts with chicks from neighbouring nests. To test this, we first cross-fostered full clutches between and within high- and low-density parts of the colony, and then used ultra-wideband tags to track free-ranging chicks. In line with our predictions, we found that chicks reared in denser areas had a lower movement activity and smaller home ranges. However, these chicks still had more social contacts, although not necessarily with a higher number of unique individuals. Pre-natal breeding density had no significant effect on any of the parameters. We conclude that parental nest choice strongly affects the early social environment of their chicks, which can shape the development of their (social) phenotype, with potentially long-lasting consequences., Competing Interests: We declare we have no competing interests., (© 2024 The Authors.)

La costa vasca constituye un área de paso e invernada de gaviotas en el Golfo de Vizcaya y éste a su vez en el Paleártico sudoccidental. Este trabajo se establece con el fin de determinar la importancia relativa de las especies que frecuentan la región en invierno, estimar su abundancia, identificar las zonas más importantes y evaluar hasta qué punto un censo único representa bien la abundancia de gaviotas de un invierno. Estructuralmente, hay dos tipos de estuarios en la costa vasca: aquellos en los que la gaviota reidora Chroicocephalus ridibundus (L. 1766) muestra niveles de abundancia relativa comparables a los de la gaviota patiamarilla Larus michahellis Naumann 1840 y aquellos en los que domina esta última, que por otro lado acumula el 66,5% de la abundancia de gaviotas en la costa vasca. La estima de la abundancia basada en un modelo log-lineal aportó un valor medio de unas 4500 gaviotas para el invierno de 2019/20 (con una probabilidad al 95% de que el valor real se sitúe en el rango de 2500 a 7500 gaviotas). En cuanto a las zonas más importantes de la región para la invernada de gaviotas, destacan Donostia, Txingudi, Urdaibai y Ondarroa. Observamos, además, un incremento de la abundancia en días lluviosos respecto a los no lluviosos, si bien este efecto se diluye ante la enorme variabilidad asociada a cada zona de muestreo. Esto supone que las cifras son altamente variables, tanto si consideramos el conjunto de especies como cada una de las más frecuentes por separado. Ante esta realidad, se concluye que los resultados de un único censo no representan las abundancias de las gaviotas que invernan en la costa vasca, por lo que se recomienda llevar a cabo varios censos simultáneos con el fin de estimar un valor medio junto a su incertidumbre asociada. ___________________________________________ The Basque coast is a migratory and wintering area for several gull species within the Gulf of Biscay and the Southwestern Palaearctic. This paper aims to assess the relative importance of those species that overwinter along this coast, estimate their abundance, identify the main areas and evaluate to what extent a single census is enough to represent their abundance. Structurally, we found two types of estuaries: those in which the black-headed gull Chroicocephalus ridibundus (L. 1766) co-dominated with the yellow-legged gull Larus michahellis Naumann 1840, and those in which the yellow-legged gull was dominant. The latter species accounted for 66.5% of the overall gull population size within the Basque coast. The mean gull population size determined by a log-linear model for all species was 4500 individuals for the winter 2019/20 (95% CI: 2500-7500 gulls). The main locations within the region were Donostia, Txingudi, Urdaibai and Ondarroa. We observed an increasing number of counts on rainy days as compared to dry days but this effect was very small as compared to the high variance associated with each survey locality. In view of such a high variability, it can be concluded that the results from a single census are not enough to estimate the population size of those gulls overwintering within the region. Several censuses throughout the winter are recommended to obtain a more robust estimate.

Human impacts alter landscapes with consequences for the distribution and availability of high‐quality food resources to populations inhabiting those landscapes, which may impact on the reproductive output of individuals in those populations. The sensitivity of wild populations to changes in food resources may vary among stages of the annual cycle. For example, in birds, effects are likely to be greater during costly stages such as egg production. Here we compare assimilated diet (from stable isotope analysis of chick feathers) and egg traits (egg size, shape, eggshell colour and maculation, using pattern‐analysis software) in Herring Gulls Larus argentatus, across seven colonies in southwest Scotland and Northern Ireland. The Herring Gull is an opportunistic, generalist forager on both marine and terrestrial resources which frequently exploits anthropogenic food sources such as fishery discards and human refuse. We found that larger eggs were laid in colonies where females consumed either a higher proportion of marine resources or terrestrial resources; smaller eggs were laid in colonies where females had an intermediate diet. In colonies where females consumed more marine items, they also laid eggs with higher maculation (intensity and size of spots) compared with colonies where females mainly consumed terrestrial food. We also found smaller and more pointed eggs, suggestive of resource shortages, in larger colonies. Generalist foragers are often thought to have the capacity to buffer themselves against changes in the food web, provided that enough alternative food is available. However, this study highlights that specializing on the most profitable or available resources has consequences for egg traits even in an opportunistic generalist forager exploiting a large range of habitats. If variation in egg traits is related to reproductive output, then understanding the impact of assimilated diet on reproduction early in the breeding season can provide important insights into how populations will respond to landscapes altered by human impact. [ABSTRACT FROM AUTHOR]

In 2018, the Nevada Bird Records Committee reviewed 56 reports from the period 23 May 1981-23 July 2018; 46 were endorsed. No new species were added to the state list, which stands at 489 species. The review list underwent a major revision in August 2018, reducing the number of full species requiring review from 141 to 108; two additional subspecies remain on the list. [ABSTRACT FROM AUTHOR]

The relationship between the rate of predation and prey abundance is an important component of predator–prey dynamics. However, functional responses are less straightforward when multiple predators compete for shared prey. Interactions among competing predators can reduce or enhance effects of predation on prey populations. Because many avian populations experience high rates of nest predation, understanding the role of specific predators on nest mortality will lead to more informed conservation and management strategies which attempt to increase productivity by removing certain predators or managing habitat to limit their impact.Our goal was to evaluate effects of specific predators and the influence of nest abundance on nest mortality.We monitored snowy plover Charadrius nivosus nests across 7 years at two study areas in Utah, USA, with remote cameras. We modelled predator‐specific hazard rates for nest mortality in a Bayesian framework to assess relationships between competing predators and the role of nest abundance on predator‐specific hazard rates.We found that hazard rates for nest mortality by gulls Larus spp. decreased with increasing nest abundance, whereas nest mortality by foxes Vulpes spp. and ravens Corvus corax initially increased, indicating that dietary switching may occur when nests become more abundant. Nest mortalities of specific predators were often not independent and ranged between compensatory (e.g. mammalian mesopredators) and superadditive (e.g. avian predators) across the breeding season.The non‐independence between nest mortalities suggests that reductions in some predators may not translate to additive increases in overall nest success. Analyses of cause‐specific mortality are rarely applied to avian nests, but examination of interacting impacts among competing predators on nest survival may provide insight into specific drivers of avian population dynamics. A free Plain Language Summary can be found within the Supporting Information of this article. [ABSTRACT FROM AUTHOR]

The breeding numbers of seabirds, including Great Cormorant, Phalacrocorax carbo, Japanese Cormorant, Phalacrocorax capillatus, Black-tailed gull, Larus crassirostris, and Slaty-backed gull, Larus schistisagus along the coastline from Cape Soya to Shari Town was censused. Confirmed were 462 nests of Great Cormorant on the nearshore bank at 4 sites, 312 nests of Japanese Cormorant at 7 sites, only one nest of Black-tailed Gull, except for the Menashidomari colony, and 1,523 nests of Slaty-backed Gull at 19 sites of which 84.5% were found on the nearshore bank. Breeding number of Slaty-backed Gulls increased between 2014 and 2019 at 4 sites. [ABSTRACT FROM AUTHOR]

Large gulls are omnivorous predators that are typically associated with coastal environments, but gull colonies vary in their proximity to the coast. Because the diet of central-place foragers is often dictated by resource availability within range of the central place, we investigated inter-colony and interspecific differences in the diet of Great Black-backed Gulls Larus marinus and Herring Gulls L. argentatus at multiple inshore colonies (< 20 km) and one offshore colony (> 60 km; Funk Island) on the northeast Newfoundland coast, Canada. Values of δ15N and δ13C in whole blood of gull chicks and adults (incubating) were used to compare isotopic niche breadth (standard ellipse area) and trophic level ( δ15N) between species (adults and chicks) and colonies (chicks only). Herring Gull chicks had higher δ15N at the offshore colony relative to inshore colonies, indicating that these chicks were provisioned with higher trophic level resources (e.g., seabird eggs/chicks) compared to lower trophic level resources (e.g., benthic invertebrates) at inshore colonies. Great Black-backed Gull chicks had higher δ15N than Herring Gull chicks at all colonies, indicating they were consistently provisioned with higher trophic level resources. Isotopic niche breadth was broader for Great Black-backed Gull chicks raised inshore relative to offshore, indicating a wider variety of resources provisioned at inshore colonies relative to the offshore colony. Incubating adult Great Black-backed Gulls incorporated higher trophic level prey and had a narrower isotopic niche breadth than incubating Herring Gulls at the same inshore colony, indicating that they have a more specialized diet of higher trophic level than Herring Gulls. We suggest, based on our results, that the differential availability of food resources proximal to colonies influences the diet of these two sympatric gull species, thereby informing region-specific gull management programs. [ABSTRACT FROM AUTHOR]

Investigating the seasonal movements of migratory seabirds is essential to our understanding of their basic life history and conservation needs. Using satellite telemetry, we studied the migration and non-breeding distribution of Thayer's Gulls Larus glaucoides thayeri, a little known North American gull. Four adult birds that were tracked from a colony in the Canadian high Arctic migrated south overland, crossing multiple mountain ranges to arrive at the coast between southeast Alaska and northwest British Columbia. The subsequent wintering distribution differed greatly among individuals occupying ranges as far north as Yakutat Bay, Alaska (59.7°N) and as far south as Monterey Bay, California (36.7°N). Gulls spent 62%-82% of the overwinter period in waters overlying the inner continental shelf (mean sea surface temperature 8.4-11.7°C; mean distance to coast 2.6-8.8 km, mean depth 19-102 m), in areas of generally low human activity. Their remaining time was spent primarily onshore in coastal (15%-20%) or inland areas (4%-23%) composed of natural vegetated habitat with low human population density. Little time was spent in agricultural (0%-5%) or urban (0%-1.5%) environments. Our tracking study provides new insights into the basic natural history of this species. This knowledge should help in the development of conservation strategies for the management of Thayer's Gull populations. [ABSTRACT FROM AUTHOR]

The article provides information on the observation of birds such as falcon, phylloscopus and anas crecca. Topics include nesting of the arctic tern bird, increasing bird population by importing birds of various species and species ordered according tothe bird list of Switzerland such as gulls of larus subspecies.

We document replacement of primaries during the prealternate molt in two and possibly three species of North American gulls of the genus Larus, including the first report of such replacement in an adult Yellow-footed Gull (L. livens), the first report in the Lesser Black-backed Gull (L. fuscus) in the Americas, and possibly the first report for the American Herring Gull (L. argentatus smithsonianus). The incidence and extent of replacement of primaries is greater during the second prealternate than during subsequent prealternate molts, which is likely related to second-cycle molts in Larus being earlier than the subsequent molts. The second prealternate molt of the Lesser Black-backed Gull includes up to all flight feathers (but not all wing coverts). The sequence of replacement of primaries during the prealternate molt matches that of the prebasic molt, starting at the innermost primary and proceeding distally; however, the sequence of replacement of secondaries can differ from that during the prebasic molt, perhaps because of a difference in the underlying mechanisms controlling these molts. Prealternate molt of inner primaries can begin before prebasic molt of outer primaries is completed, a pattern resembling Staffelmauser, but all evidence suggests that the ensuing prebasic molt of the primaries begins at p1, as in terns, rather than at the point where the inner molt wave is suspended, as during Staffelmauser in other large volant birds. We propose that the occurrence and extent of prealternate molt of the remiges in Larus is correlated with the latitude at which an individual winters and/or the timing of the prebasic molt the year before, as much as or more so than with phylogeny. The possible replacement of primaries during the second prealternate molt in North American but not European subspecies of the Herring Gull could relate to some individuals of the American subspecies wintering farther south. [ABSTRACT FROM AUTHOR]

Tree mortality incurred through the nesting habits of Double-crested Cormorants ( Phalacrocorax auritus) can cause human-wildlife conflicts, often resulting in the lethal control of cormorants to reduce local population numbers in North America. In a protected area in Toronto, Ontario, Canada, that supports the largest colony of Double-crested Cormorants in North America, a non-lethal management approach to mitigate cormorant-induced tree mortality was adopted by the site managers in 2008. Double-crested Cormorants were managed for space occupancy rather than population size, with the main objective of minimizing tree mortality while supporting the cormorant population. Targeted non-lethal deterrence of tree-nesting Double-crested Cormorants was labor intensive, but effective in protecting trees. Between 2008 and 2016, the tree-nesting colony was prevented from expanding. Accessing ground-nesting Double-crested Cormorants only at night to avoid Larus sp. predation of Double-crested Cormorant nests appeared to be highly effective in minimizing disturbance; the ground-nesting colony expanded 899% over an 8-year period, with a 44% decrease in tree nesting. Ground-nesting Double-crested Cormorants had less impact on trees than tree-nesting individuals, and this spatially focused approach allowed for the sustained existence of a thriving colony. [ABSTRACT FROM AUTHOR]

Predation risk is an important environmental factor for animal populations, expected to trigger maternal effects to prepare offspring for living in an environment with predators. Yet, evidence of adaptive anticipatory maternal effects in wild animals is still weak. Here, we explored this question in a wild colony of yellow-legged gulls, Larus michahellis. To this aim, prior to laying we exposed mothers to either mink decoys or nonpredator rabbit decoys and explored the antipredator behavior of 118 chicks at the age of 2 days. We found that chicks from second-laid eggs by predator-exposed mothers crouched faster after hearing a playback with adult alarm calls than chicks from second-laid eggs by control mothers. Besides, chicks from third-laid eggs by predator-exposed mothers were lighter than control chicks, but this was not due to differences in egg volume. Our results suggest that predator-exposed mothers modified offspring phenotype via eggs to cope with predators, although only in chicks from second-laid eggs. Maternal transference of corticosterone could underlie chick behavioral plasticity. Results support the role of maternal effects as a form of phenotype programming to forewarn offspring about environmental hazards. [ABSTRACT FROM AUTHOR]

Lakes in arid and semi-arid regions have an irreplaceable and important role in the local environment and wildlife habitat protection. Relict Gull (Larus relictus), which is listed as a “vulnerable” bird species in the IUCN Red List, uses only islands in lakes for habitat. The habitat with the largest colonies in Hongjian Lake (HL), which is located in Shaanxi Province in China, has been severely threatened by persistent lake shrinkage, yet the variations in the area of the lake and the islands are poorly understood due to a lack of in situ observations. In this study, using the Modified Normalized DifferenceWater Index, 336 Landsat remote sensing images from 1988–2015 were used to extract the monthly HL water area and lake island area, and the driving factors were investigated by correlation analysis. The results show that the lake area during 1988–2015 exhibited large fluctuations and an overall downward trend of -0.94 km2/year, and that the lake area ranged from 55.02 km2 in 1997 to 30.90 km2 in 2015. The cumulative anomaly analysis diagnosed the lake variations as two sub-periods with different characteristics and leading driving factors. The average and change trend were 52.88 and 0.21 km2/year during 1988–1998 and 38.85 and -1.04 km2/year during 1999–2015, respectively. During 1988–1998, the relatively high precipitation, low evapotranspiration, and low levels of human activity resulted in a weak increase in the area of HL. However, in 1999–2015, the more severe human activity as well as climate warming resulted in a fast decrease in the area of HL. The variations in lake island area were dependent on the area of HL, which ranged from 0.02 km2 to 0.22 km2. As the lake size declined, the islands successively outcropped in the form of the four island zones, and the two zones located in Northwest and South of HL were the most important habitats for Relict Gull. The formation of these island zones can provide enough space for Relict Gull breeding. [ABSTRACT FROM AUTHOR]

Acquired carbapenemases currently pose one of the most worrying public health threats related to antimicrobial resistance. A NDM-1-producing Salmonella Corvallis was reported in 2013 in a wild raptor. Further research was needed to understand the role of wild birds in the transmission of bacteria resistant to carbapenems. Our aim was to investigate the presence of carbapenem-resistant Escherichia coli in gulls from southern France. In 2012, we collected 158 cloacal swabs samples from two gull species: yellow-legged gulls ( Larus michahellis) that live in close contact with humans and slender-billed gulls ( Chroicocephalus genei) that feed at sea. We molecularly compared the carbapenem-resistant bacteria we isolated through culture on selective media with the carbapenem-susceptible strains sampled from both gull species and from stool samples of humans hospitalized in the study area. The genes coding for carbapenemases were tested by multiplex PCR. We isolated 22 carbapenem-resistant E. coli strains from yellow-legged gulls while none were isolated from slender-billed gulls. All carbapenem-resistant isolates were positive for bla VIM-1 gene. VIM-1-producing E. coli were closely related to carbapenem-susceptible strains isolated from the two gull species but also to human strains. Our results are alarming enough to make it urgently necessary to determine the contamination source of the bacteria we identified. More generally, our work highlights the need to develop more bridges between studies focusing on wildlife and humans in order to improve our knowledge of resistant bacteria transmission routes. [ABSTRACT FROM AUTHOR]

Environmental stressors have the potential to induce perturbations in the development of young individuals, leading to aberrant and unstable development. This may manifest as fluctuating asymmetry (FA; small, non-directional changes in the bilateral symmetry of morphological traits). Although widely regarded as a proxy for stress effects, the use of FA as a biomarker is still a topic of much debate. We investigated the applicability of FA as an indicator of nutritional stress (brought about by energetic constraints) by experimental manipulation of the diet composition and quantity during the growth of Lesser Black-backed Gull (Larus fuscus) chicks. FA as an endpoint was measured across the tarsus, wing and 10th primary feather when chicks reached 30 days of age. Although levels of asymmetry were found to increase with stress in the feather, relationships with tarsus and wing FA were mixed and mostly non-significant. Furthermore, we did not find any correlations in unsigned FA between traits, indicating the absence of organism-wide asymmetry. Our study was therefore unable to find unequivocal evidence in support of the application of FA as a reliable estimator of nutritional stress. [ABSTRACT FROM AUTHOR]

The presence of persistent organic pollutants in the environment manifests itself most strongly in the marine trophic chain, where the highest link is comprised of seabirds. At the same time, seabirds are excellent indicators of contamination in their habitat. The present study concentrates on toxic substances: polychlorinated dibenzo-p-dioxin (PCDDs), polychlorinated dibenzofurans (PCDFs) and chlorinated organic pesticides (OCPs) accumulated in the livers, pectoral muscles and brains of dead gulls collected along the Polish coast of the Baltic Sea in the years 2010–12. The highest toxic equivalence was determined in the livers of Larus argentatus (TEQ (birds TEF) −28.3 pg g −1 ww) and Larus marinus (TEQ (birds TEF) −29.9 pg g −1 ww.). However, the toxic equivalence of muscles was lower and amounted to 3.9 pg g −1 ww. and 7.8 pg g −1 ww. respectively for the two species. The lowest toxic equivalence was found in the brains of birds, where only one, the most toxic, 2,3,7,8 TCDD congener was found (TEQ (birds TEF) 0.87 pg g −1 ww). The highest concentration of chloroorganic pesticides was determined in the brains of the birds (total OCP 167.8 pg g −1 ww.), lower concentrations were found in the livers (total OCP 92.1 pg g −1 ww.) and muscles (total OCP 43.1 pg g −1 ww.). With regard to pesticides, the highest proportion in the total OCP content was constituted by DDT and its isomers (liver 81%, muscles 77% and brain 55%). High concentrations of the studied pollutants in the livers of gulls found dead on the coast of the Southern Baltic could have been effected by levels of contamination in the birds’ last meals, which resulted in a seven-fold increase of the liver’s toxic equivalence and a two-fold increase in OCP concentration in relation to muscles. [ABSTRACT FROM AUTHOR]

The present study documents the first sightings of the migratory Pallas's Gull at two different locations (Cholamu Lake and Singtam Valley) in the eastern Himalayan state of Sikkim in India. We recommend that long term surveys are required to determine and establish the distribution and status of the species in the state. [ABSTRACT FROM AUTHOR]

Species complexes that have undergone recent radiations are often characterized by extensive allele sharing due to recent ancestry and (or) introgressive hybridization. This can result in discordant evolutionary histories of genes and heterogeneous genomes, making delineating species limits difficult. Here we examine the phylogenetic relationships among a complex group of birds, the white-headed gulls (Aves: Laridae), which offer a unique window into the speciation process due to their recent evolutionary history and propensity to hybridize. Relationships were examined among 17 species (61 populations) using a multilocus approach, including mitochondrial and nuclear intron DNA sequences and microsatellite genotype information. Analyses of microsatellite and intron data resulted in some species-based groupings, although most species were not represented by a single cluster. Considerable allele and haplotype sharing among white-headed gull species was observed; no locus contained a species-specific clade. Despite this, our multilocus approach provided better resolution among some species than previous studies. Interestingly, most clades appear to correspond to geographic locality: our BEAST analysis recovered strong support for a northern European/Icelandic clade, a southern European/Russian clade, and a western North American/ canus clade, with weak evidence for a high latitude clade spanning North America and northwestern Europe. This geographical structuring is concordant with behavioral observations of pervasive hybridization in areas of secondary contact. The extent of allele and haplotype sharing indicates that ecological and sexual selection are likely not strong enough to complete reproductive isolation within several species in the white-headed gull complex. This suggests that just a few genes are driving the speciation process. [ABSTRACT FROM AUTHOR]

Conditions during early life, including maternal cohort effects, can influence the future fitness of individuals. This may be particularly true for long-distance migrating birds, because, apart from conditions experienced by cohorts during rearing, conditions during early life in regions far from breeding grounds may also influence their population dynamics. Very little is known about the fitness consequences of those conditions experienced by juveniles after independence, especially in wild populations and for longlived birds. We used multi-event capture-recapture-recovery models and a unique 26-year dataset for the Audouin's gull (Larus audouinii) to assess for the first time whether survival was influenced by early conditions, both during the rearing period (i.e. a maternal cohort effect potentially affected by density dependence) and the first winter (i.e. a cohort effect driven by climate when birds disperse to wintering grounds). Our results show that juvenile survivalwas highly sensitive to early-life conditions and that survival decreased with stronger density dependence and harsh climate. The two consecutive cohort effects were of similar magnitude and they may represent a selection filter. Thus, early-life conditions had a strong impact on survival, and neglecting this complexity may hinder our understanding on how populations of long-lived animals fluctuate and respond to perturbations. [ABSTRACT FROM AUTHOR]