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Urbanization is a major form of landscape transformation that often results in habitat degradation and loss for birds. However, effects on avian populations are trait- and context-dependent, and persistence at urban patches is likely to be a function of habitat availability at the landscape scale. Here, we aimed to assess the breeding performance and foraging ecology of a widespread shorebird, the American Oystercatcher Haematopus palliatus, during the 2017–2018 and 2018–2019 breeding seasons at a small urban beach surrounded by a heterogeneous landscape in southern Brazil. Twelve pairs were able to breed consistently and successfully fledge offspring in 20% of nesting attempts at the urban site, with overall productivity of 0.37 fledglings per pair. Food remains collected within seven successful nesting territories and stable isotope analysis in blood samples of adults and chicks indicated that oystercatchers relied on invertebrates from both sandy beaches and rocky shores as food resources. Furthermore, eight out of 21 color-marked individuals from the urban beach were consistently recorded using an insular marine protected area ~ 2 km offshore, revealing a connection between unprotected and protected habitat patches. Although oystercatchers had to perform multiple foraging trips in order to collect food, the ability to explore different environments in the landscape may be critical in the region, especially with human disturbance at its peak on beaches during the summer. Our findings suggest that shorebirds breeding in urban areas may rely on heterogeneous landscapes, where distinct and protected habitat patches can provide complementary resources that allow breeding successfully.

The American Oystercatcher, Haematopus palliatus, is a widespread shorebird in both North and South America. Despite its large distribution along the Brazilian coast, there is a paucity of breeding information about the species across this vast region. Herein, we monitored the breeding biology of the species during three consecutive breeding seasons on three sandy beaches in southern Brazil. The nesting season extended from July to January with a mode clutch size of two eggs (mean ± SD = 1.9 ± 0.6, n = 63). The majority of the nests recorded were found in the sandy dunes habitat adjacent to the beachfront, with a low cover of herbaceous native vegetation, reinforcing the importance of this habitat for the conservation of the species.

Many coastal-dependent species have undergone large-scale population declines due to impacts from habitat loss, including American oystercatchers (Haematopus palliatus). Islands along the Big Bend region of Florida’s Gulf Coast provide important nesting habitat for oystercatchers, but reproductive success here is low and habitat degradation and loss are a major concern. To determine rates and characteristics of habitat loss, we quantified changes in island sizes within two major breeding areas of the Big Bend: the Barge Canal spoil islands and natural islands at Cedar Key. We digitized aerial photographs from the past ~ 40 years, measured area and shoreline retreat of nesting islands, and identified trends over time by fitting linear mixed effects models. The total area of the ten Barge Canal spoil islands decreased by 55% between 1979 and 2016. At Cedar Key, the total area of the six islands measured decreased by 39% between 1974 and 2016, 85% of which occurred after 1995, indicating an increase in erosion rates correlated with oyster reef declines. Changes in available nesting habitat varied between the Barge Canal and Cedar Key islands due to differences in physical attributes; however, all islands significantly decreased in size over time. Given the long life and high site fidelity of American oystercatchers, these islands may currently be acting as an ecological trap for this species. Climate change, sea-level rise, and loss of oyster reefs are likely to continue to drive oystercatcher habitat loss throughout their range; thus, creation and restoration of oyster reefs and nesting islands will become increasingly important.

Increasing goose population sizes gives rise to conflicts with human socioeconomic interests and in some circumstances conservation interests. Grazing by high abundances of geese in grasslands is postulated to lead to a very short and homogeneous sward height negatively affecting cover for breeding meadow birds and impacting survival of nests and chicks. We studied the effects of spring grazing barnacle geese Branta leucopsis and brent geese Branta bernicla on occupancy of extensively farmed freshwater grasslands by nesting and brood‐rearing waders on the island Mandø in the Danish Wadden Sea. We hypothesized that goose grazing would lead to a shorter grass sward, negatively affecting the field occupancy by territorial/nesting and chick‐rearing waders, particularly species preferring taller vegetation. Goose grazing led to a short grass sward (, Grazing by high abundances of geese in grasslands is postulated to lead to a very short and homogeneous sward height negatively affecting cover for breeding meadow birds and ultimately impacting survival of nests and chicks. Despite very intensive goose grazing in spring, our field study could not detect any negative effect on the field occupancy by nesting nor chick‐rearing waders.

Shellfish, including the key species the common cockle Cerastoderma edule, living and feeding in waters contaminated by infectious agents can accumulate them within their tissues. It is unknown if microbial pathogens and microparasites can subsequently be transmitted via concomitant predation to their consumers, including shorebirds. The objective of this study was to assess if pathogens associated with C. edule could be detected seasonally in the faeces of shorebirds that feed on C. edule and in the physical environment (sediment) in which C. edule reside, along the Irish and Celtic Seas. Two potentially pathogenic global groups, Vibrio and Haplosporidia, were detected in C. edule. Although Haplosporidia were not detected in the bird faeces nor in the sediment, identical strains of Vibrio splendidus were detected in C. edule and bird faecal samples at sites where the oystercatcher Haematopus ostralegus and other waders were observed to be feeding on cockles. Vibrio spp. prevalence was seasonal and increased in C. edule and bird faecal samples during the warmer months, possibly due to higher seawater temperatures that promote the replication of this bacteria. The sediment samples showed an overall higher prevalence of Vibrio spp. than the bird faecal and C. edule samples, and its detection remained consistently high through the sites and throughout the seasons, which further supports the role of the sediment as a Vibrio reservoir. Our findings shed light on the fact that not all pathogen groups are transmitted from prey to predator via feeding but bacteria such as V. splendidus can be. As most of the wading birds observed in this study are migratory, the results also indicate the potential for this bacterium to be dispersed over greater geographic distances, which will have consequences for areas where it may be introduced.

Shorebird populations, especially those feeding on shellfish, have strongly declined in recent decades and identifying the drivers of these declines is important for conservation. Changing food stocks are thought to be a key driver of these declines and may also explain why trends have not been uniform across Europe's largest estuary. We therefore investigated how winter population trends of Eurasian oystercatchers (Haematopus ostralegus) were linked to food availability in the Dutch Wadden Sea. Our analysis incorporated two spatial scales, a smaller scale focused on roost counting areas and food available to birds in these areas and a larger spatial scale of tidal basins. A novelty in our study is that we quantify the connectivity between roosting and foraging areas, identified from GPS tracking data. This allowed us to estimate food available to roosting birds and thus how food availability may explain local population trends. At the smaller spatial scale of roost counting areas, there was no clear relationship between available food and the number of roosting oystercatchers, indicating that other factors may drive population fluctuations at finer spatial scales. At the scale of tidal basins, however, there was a significant relationship between population trends and available food, especially cockle Cerastoderma edule,. Mortality and recruitment alone could not account for the large fluctuations in bird counts, suggesting that the site choice of wintering migratory oystercatchers may primarily drive these large fluctuations. Furthermore, the relationship between oystercatcher abundance and benthic food stocks, suggests winter shorebird counts could act as ecological indicators of ecosystem health, informing about the winter status of food stocks at a spatial scale of tidal basins.

Wading birds can be found breeding in a myriad of habitats and ecosystems across Europe that vary widely in their land-use intensity. Over the past few decades, wader breeding populations have declined steeply in habitats ranging from natural undisturbed ecosystems to intensively managed farmland. Most conservation science has focused on factors determining local population size and trends which leave cross-continental patterns and the associated consequences for large-scale conservation strategies unexplored. Here, we review the key factors underlying population decline. We find land-use intensification in western Europe and mostly agricultural extensification and abandonment in northern, central and eastern Europe to be important drivers. Additionally, predation seems to have increased throughout the breeding range and across all habitats. Using collected breeding density data from published and grey literature, we explore habitat specificity of wader species and, of the most widely distributed species, how breeding densities change across a land-use intensity gradient. We found that two-thirds of all examined wader species have relatively narrow breeding habitat preferences, mostly in natural and undisturbed ecosystems, while the remaining species occurred in most or all habitats. The most widespread generalist species (black-tailed godwit, northern lapwing, common redshank, Eurasian oystercatcher, common snipe and ruff) demonstrated peak breeding densities at different positions along the land-use intensity gradient. To conserve both diverse wader communities and viable meta-populations of species, a diversity of habitats should be targeted ranging in land-use intensity from natural ecosystems to medium intensity farmland. Alongside, strategies should be designed to moderate predation of wader clutches and chicks.

We estimated the influence of human disturbance and environmental factors on territory establishment in common ringed plovers Charadrius hiaticula and Eurasian oystercatchers Haematopus ostralegus, to inform the conservation of these species. We examined a 212 km stretch of coastline in the United Kingdom in 2003, mapping all breeding pairs of both study species, as well as the environmental characteristics of beaches and locations of visitors on the beach, the latter measured by filming from a light aircraft. Of the 1,003 200m sections of beach surveyed, 183 contained ringed plover territories (267 breeding pairs) and 117 contained oystercatcher territories (226 breeding pairs). 38,634 human visitors to the beach were mapped from three flights. Population densities of both ringed plovers and oystercatchers were lower in locations with high visitor numbers, even when accounting for the influence of the environmental characteristics of the beach. The two bird species showed similar rates of territory establishment at very low visitor rates, but oystercatchers showed a stronger negative response when visitor rates reached higher levels. Binary logistic regression models were used to identify areas where the birds would benefit most from reductions in the number of visitors and we illustrate how this information could be used to inform management around sites otherwise favourable for territory establishment.

Mitochondrial genes were sequenced from four specimens of the extinct Canary Islands Oystercatcher Haematopus meadewaldoi and compared with African Oystercatcher Haematopus moquini, Eurasian Oystercatcher Haematopus ostralegus and an old unidentified extralimital ‘black’ oystercatcher specimen from The Gambia. At these loci, H. meadewaldoi was approximately 99.65% identical to multiple Eurasian Oystercatcher samples and in phylogenetic trees fell within the range of genetic variation observed in that species. The mystery Gambian bird was resolved as an extralimital H. moquini. We conclude that H. meadewaldoi was most likely a recently diverged melanistic morph or subspecies of H.ostralegus, although further genomic studies will be required to determine whether there has been a period of isolation followed by introgression.

Changes in the frequency of extreme climatic events (ECEs) can have profound impacts on individual fitness by degrading habitat quality. Organisms may respond to such changes through habitat selection, favouring those areas less affected by ECEs; however, documenting habitat selection in response to ECEs is difficult in the wild due to the rarity of such events and the long-term biological data required. Sea level rise and changing weather patterns over the past decades have led to an increase in the frequency of coastal flooding events, with serious consequences for ground nesting shorebirds. Shorebirds therefore present a useful natural study system to understand habitat selection as a response to ECEs. We used a 32-year study of the Eurasian oystercatcher (Haematopus ostralegus) to investigate whether habitat selection can lead to an increase in nest elevation and minimize the impacts of coastal flooding. The mean nest elevation of H. ostralegus has increased during the last three decades. We hypothesized that this change has been driven by changes in H. ostralegus territory settlement patterns over time. We compared various possible habitat selection cues to understand what information H. ostralegus might use to inform territory settlement. There was a clear relationship between elevation and territory settlement in H. ostralegus. In early years, settlements were more likely at low elevations but in more recent years the likelihood of settlement was similar between high and low elevation areas. Territory settlement was associated with conspecific fledgling output and conspecific density. Settlement was more likely in areas of high density and areas with high fledgling output. This study shows that habitat selection can minimize the effects of increasingly frequent ECEs. However, it seems unlikely that the changes we observe will fully alleviate the consequences of anthropogenic climate change. Rates of nest elevation increase were insufficient to track current increases in maximum high tide (0.5 vs. 0.8 cm/year). Furthermore, habitat selection cues that rely on information from previous breeding seasons (e.g. conspecific fledgling output) may become ineffective as ECEs become more frequent and environmental predictability is diminished.

[In 2008-2014 wader and seabird nesting pairs were censused along the 220-km long coastline of the NE Adriatic Sea, in the Veneto and Friuli-Venezia Giulia regions (NE Italy). Fourteen species were regularly breeding, with an annual mean of 20,610 pairs (±1553, 1 SD). The most abundant species was the Yellow-legged Gull (about 13,400 pairs on average, 65% of the whole population of the study area), followed by the Common Tern (1670 pairs, 8.1%) and Common Redshank (1525 pairs, 7.4%). The whole population of waders and seabirds increased with an annual rate, estimated with the TRIM software, of +0.8%, with a greater increase (+4.3%) if the Yellow-legged Gull was not included. Twelve species were stable or increasing; only the yellow-legged gull (-1%) and the common redshank (-2.4%) were decreasing. The populations of several species exceed 10% of those estimated for the whole of Italy; those of the Eurasian Oystercatcher, Common Redshank and Sandwich Tern are among the most important in the whole Mediterranean. On average, about 8860 pairs (43%) nest in the Venice lagoon, 6,400 pairs (31%) in the Po Delta, 5100 pairs (25%) in the Friuli-Venezia Giulia lagoons. Among nesting habitats, semi-natural (such as the fish farms) and man-made sites (dredge islands) make each year about 70% of the nesting pairs. Saltmarsh islets host large numbers of Common Redshank and Sandwich Tern, while along the beach zone the only abundant species are the Yellow-legged Gull and the Eurasian Oystercatcher. The major conservation threats observed in the study area were the erosion of littoral islands, the uncontrolled occurrence of sunbathers along the beaches, the vegetation overgrowth at dredge islands, the increasing frequency of saltmarsh submersion by high tides, the strong fluctuations of water levels inside the fish farms.] [Article in Italian]

Intertidal zone mussels can face threats from a variety of predatory species during high and low tides, and they must balance the threat of predation against other needs such as feeding and aerobic respiration. Black oystercatchers (Haematopus bachmani) on the Pacific coast of North America can depend on the mussel Mytilus californianus for a substantial portion of their diet. Observations suggest that oystercatchers tend to focus on mussels beginning to gape their valves during rising tides, following periods of aerial emersion. We present detailed, autonomous field measurements of the dynamics of three such predation events in the rocky intertidal zone. We measured accelerations of up to 4 g imposed on mussels, with handling times of 115–290 s required to open the shell and remove the majority of tissue. In each case a single oystercatcher attacked a mussel that had gaped the shell valves slightly wider than its neighbors as the rising tide began to splash the mussel bed, but no other obvious characteristic of the mussels, such as body temperature or orientation, could be linked to the oystercatcher's individual prey choice.

Made available in DSpace on 2019-10-04T12:35:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-01-01 Foundation for Research Support of the State of Rio Grande do Sul (FAPERGS) Wildlife Conservation Society (CWS) Plastic has become abundant in the oceans and proved to be a threat to marine and coastal fauna. In this study, we present the first record of synthetic debris ingested by the shorebird American Oystercatcher (Haematopus palliatus) in Brazil. We collected 24 stomach contents from October 2007 to October 2015 and 58% were juveniles. Synthetic materials were found in 100% of stomachs. Used plastic fragments and plastic pellets were the most frequent items, beige and white were more common colors. Synthetic material may be unintentionally ingested directly through substrate consumption or indirectly through prey consumption. Hence, debris ingestion may be common, representing an impact to coastal birds. Based on our results, we hope to highlight the need for public policies to reduce the disposal of synthetic debris in the oceans and beaches. Univ Vale Rio dos Sinos, Posgrad Biol, UNISINOS, Ave Unisinos 950, BR-93020190 Sao Leopoldo, RS, Brazil Univ Estadual Paulista, Posgrad Ecol & Biodiversidade, Dept Ecol, BR-13506900 Rio Claro, SP, Brazil Univ Estadual Paulista, Posgrad Ecol & Biodiversidade, Dept Ecol, BR-13506900 Rio Claro, SP, Brazil Foundation for Research Support of the State of Rio Grande do Sul (FAPERGS): 09/0574-7 Foundation for Research Support of the State of Rio Grande do Sul (FAPERGS): 2409-2551/12-0 Wildlife Conservation Society (CWS): 2008-05 Wildlife Conservation Society (CWS): 2009-05

Background Anthropogenic disturbance can negatively affect an animal’s energy budget by evoking movement responses. Existing research focuses mainly on immediate displacement as a disturbance effect, since this can be easily observed in the field. However, effects on movement over longer timescales are poorly examined and it is largely unknown if and to what extent they reflect immediate responses. Longer-term responses could for example be larger than immediate responses if birds, after disturbance, return to the original location and thereby travel twice the immediate disturbed distance. Methods We combined GPS tracking data with observational data to quantify the effects of anthropogenic (air force and walkers) and non-anthropogenic disturbances on distances travelled by roosting Eurasian Oystercatchers (Haematopus ostralegus) during the non-breeding season. We compared immediate displacement after a disturbance with distance travelled during the entire high tide period (longer-term response), while accounting for environmental factors. Additionally, we calculated energy expenditure due to disturbance based on observed disturbance frequencies. Results Disturbance resulted in an immediate displacement response of ~ 200 m (median). Air force disturbances tended to yield larger immediate responses than walker and, especially, than non-anthropogenic disturbances. Longer-term responses and immediate responses were approximately similar, suggesting that, over longer timescales, spatial disturbance effects in the study area remain confined to immediate effects. However, disturbances were infrequent (0.17 disturbances per bird per hour) and most disturbances were of natural origin (62%). Consequently, anthropogenic disturbance of roosting oystercatchers in the study area on average costs 0.08% of the daily energy expenditure. Conclusions Our results suggest that immediate spatial responses to disturbance can be a useful proxy for spatial responses over longer timescales. Over the non-exhaustive range of conditions investigated, energetic consequences of spatial disturbance responses for an oystercatcher in the study area are marginal due to low disturbance levels.

The population of the continental oystercatcher subspecies in the conditions of the middle reaches of the Medveditsa River in the nesting period of 1996–2008 was stable, namely, three pairs, out of which two, rarely three, nested annually. The clutch size was 2–3 eggs. Our many-year survey has established a tendency toward a significant decrease in the reproductive success against the background of transformations of nesting and feeding habitats, which is determined by the long-term tendency toward a reduction in the water level in the river.

Habitat characteristics and microhabitat of organisms pose a number of choices to foraging species, for example where and how to search for prey, which prey to select and what foraging technique to employ. Predators can enhance the profitability of foraging by adapting their strategies flexibly in relation to prey characteristics and environmental factors. To investigate the influence of rocky shore characteristics viz., condition of rock, position of limpet on the rock, stage of tide, and limpet opening technique of oystercatcher on the profitability of limpet foraging, a total of 193 attacks on limpets (Patella spp.) by Eurasian oystercatchers (Haematopus ostralegus) were made on Lundy Island, UK, using focal animal sampling. Multiple regression revealed that profitability was influenced by the condition of the rock and the limpet opening technique employed by oystercatchers. The profitability of the limpet opening technique appears to be associated with the condition of the rock. Oystercatchers forage by adapting their foraging strategy in accordance with the nature of the rocks i.e. wetness on which they are foraging.

At least 11 animal species in the study area are threatened or near-threatened at a global scale: thick-shelled mussel Unio crassus, curlew Numenius arquata, black-tailed godwit Limosa limosa, northern lapwing Vanellus vanellus, Eurasian oystercatcher Haematopus ostralegus, velvet scoter Melanitta fusca, European mink Mustelalutreola, pond bat Myotis dasycneme, garden dormouse Eliomys quercinus, Atlantic sturgeon Acipenser sturio. The state of things with these species was found to be in many respects similar to that with pearl mussels before the present study. Though rare and vulnerable, they have been almost unstudied for decades, attract little scientific attention and are uninvolved in nature protection activities. The present study of pearl mussels may serve as a promising model of their research.

As variações espaço-temporais na disponibilidade de recursos alimentares representam um desafio á sobrevivência de organismos especialistas. O ostreiro Americano (ou só “ostreiro”) Haematopus palliatus é uma espécie costeira, considerada especialista na predação de moluscos bivalves, contudo, o ambiente e as espécies disponíveis para a sua alimentação variam ao longo da sua distribuição. A plasticidade trófica associada à disponibilidade de presas e habitat em áreas de alimentação e reprodução foi hipotetizada. Entre 2017 e 2021, foram amostrados 100 indivíduos em cinco áreas reprodutivas no sul do Brasil, sendo três compostas de substrato misto (arenoso e rochoso) e duas de substrato arenoso. A disponibilidade de macroinvertebrados bentônicos foi avaliada no substrato arenoso, na zona de mesolitoral. Amostras de músculo de presas potenciais e do sangue de H. palliatus foram utilizadas para análise de isótopos estáveis de carbono (į13C) e nitrogênio (į15N). A variação espaço-temporal da dieta do ostreiro foi observada através de modelos de mistura e nicho isotópico, sugerindo que é influenciada pela variabilidade de habitats de alimentação, e flutuações nos recursos alimentares. Em praias de substrato misto, o ostreiro apresentou nichos isotópicos mais amplos, sugerindo um aumento na riqueza de presas com a disponibilidade de habitats para o forrageio. A contribuição média de bivalves para a dieta do ostreiro foi de cerca de 60%, mas as espécies preferenciais de bivalves variaram entre as áreas de amostragem. Houve variação interanual na dieta associada à variação na disponibilidade de macroinvertebrados em praias arenosas, em especial de outros grupos taxonômicos (i.e. não bivalves). Portanto, embora o ostreiro seja apontado como especialista em bivalves, a espécie apresentou plasticidade trófica influenciada pela variação temporal na disponibilidade de alimentos e heterogeneidade de habitat de forrageio, moldando a composição da dieta, representando um potencial para adaptação local e diferenciação intraespecífica em aves costeiras residentes. Spatiotemporal variations in the availability of food resources represent a challenge to the persistence of specialist species. The American oystercatcher (hereafter “oystercatcher”) Haematopus palliatus is a coastal species, considered a specialist on bivalves, although available feeding habitats and prey species may vary along its distribution. Trophic plasticity associated with habitat and prey availability in foraging areas was hypothesized. Between 2017 and 2021, 100 individuals were sampled in five breeding areas in southern Brazil, three composed by sandy and rocky, and two sandy only, substrates. On the mesolitoral zone, benthic macroinvertebrate availability was assessed at the sandy substrate. Muscle samples of potential prey and blood of oystercatchers were obtained for analysis of carbon (į13C) and nitrogen (į15N) stable isotopes. Spatiotemporal variation in the diet of the oystercatcher was observed through mixing models and isotopic niche, suggesting to be influenced by the variability of feeding habitats and fluctuations in the availability of food resources. In the mixed substrate sites, oystercatchers had a wider isotopic niche, suggesting an increase in prey richness in the available foraging habitats. Bivalves contribution to the diet of the oystercatcher was around 60%, but differences in the preferred bivalve species varied among areas. Interannual variation in the diet associated with variation in macroinvertebrate availability on sandy beaches was observed, especially for non-bivalve prey. Therefore, despite the oystercatcher specialization in bivalves, they presented a trophic plasticity indicated by temporal variations in food availability and heterogeneity of foraging habitats shaping dietary composition, representing a potential local adaptation for intraspecific differentiation in resident shorebirds.

This ethnographic study explores and compares the relationships that locals in Rossfjord, North Norway, have to the oystercatcher and the sea-going Arctic char respectively. Both these animals are highly valued locally, while the valuations at first look very different. The oystercatcher is protected by building bin-cases for its nesting, while the Arctic char is killed and eaten. Discussing these valuations against the value theory of David Graeber, I argue that they both connect to an underlying perception of the freedom and autonomy of wild animals, where what is not fully understood enhances an experience of wonder and appreciation of what I call the wild.

Siqueira, Airton Janes da Silva, Guzzi, Anderson, Lima, Pedro Cerqueira, Damasceno, João Paulo Tavares, Pichorim, Mauro, Fedrizzi, Carmen Elisa (2020): Reproduction of the American Oystercatcher ("piru-piru"), Haematopus palliatus Temminck 1820 (Aves: Haematopodidae), in northeastern Brazil. Journal of Natural History 54 (23-24): 1513-1524, DOI: 10.1080/00222933.2020.1814438, URL: http://dx.doi.org/10.1080/00222933.2020.1814438

The American Oystercatcher (Haematopus palliatus palliatus) is an important breeding species along the Texas Gulf Coast, particularly between Galveston Bay and Corpus Christi, Texas, USA. American Oystercatchers are considered a species of greatest conservation need and are on the priority list for conservation by the National Fish and Wildlife Foundation. American Oystercatchers feed mainly on oysters (Ostreidae) and other bivalves, which are known to accumulate significant amounts of pollutants. We determined accumulation and potential effects of environmental contaminants, particularly organochlorine (OC) pesticides and polychlorinated biphenyls (PCBs) in blood of American Oystercatchers nesting along the Texas Gulf Coast, USA during 2012 and 2013. Plasma concentrations of OCs and PCBs were low. The most commonly detected OC pesticides were HCB, HCH, α chlordane, endosulfan, methoxychlor, p,p'-DDD, and p,p'-DDE. Total p,p'-DDE concentrations ranged from 2-10 ng/mL ww and total PCB concentrations ranged from 2-54 ng/mL ww. Mean p,p'-DDE concentrations were similar among regions; however, total PCBs were significantly greater (P = 0.0056) in blood from adult birds from West Galveston Bay, Texas, USA in 2013 than in blood from young collected in 2012, mostly also from West Galveston Bay. Overall, concentrations of OC pesticides in plasma were low; however, some PCB concentrations were above the NOAEC levels that have been associated with normal reproduction in other bird species.

Una época crítica para los organismos es la reproductiva, pues de ella dependen, en parte, la salud y el tamaño de las poblaciones. Generar información sobre este aspecto permite tomar adecuadas decisiones de manejo o conservación. Para evaluar la importancia del noroeste de México en la reproducción de nueve especies de aves playeras, estudiamos, en mayo de 2017, a sus poblaciones en 12 sitios, localizados en Baja California Sur (3), Sonora (3), Sinaloa (4), límites entre Baja California y Sonora (1) y Sinaloa y Nayarit (1). Realizamos conteos y búsqueda de evidencia reproductiva, en la costa. Registramos nueve especies hipotéticamente reproductivas y un híbrido (Haematopus palliatus x H. bachmani). Obtuvimos 6,960 registros de aves playeras, donde sobresalieron Himantopus mexicanus (42%), Recurvirostra americana (32%) y H. palliatus (18.4%). Los sitios con mayores abundancias fueron Marismas Nacionales (35%), Huizache-Caimanero (13%), Yavaros-Moroncárit (12.5%) y Bahía de Tóbari (12%), todos ubicados en el continente. Para tres especies (H. palliatus, Charadrius nivosus y Ch. wilsonia) los individuos reproductores representaron un porcentaje importante de su total poblacional. Esta investigación reafirma la importancia del noroeste de México para la reproducción de aves playeras residentes, algunas protegidas por el gobierno mexicano.

In the Netherlands, breeding populations of wader meadow birds are in sharp decline. One possible cause is that breeding areas are becoming less open because of tall trees and other factors. The effects of tree lines are generally studied by means of transversal studies spanning a short period of time. We report on a longitudinal field study from 1993 to 2010 into the breeding densities of Eurasian Oystercatcher (Haematopus ostralegus), Northern Lapwing (Vanellus vanellus), Black-tailed Godwit (Limosa limosa) and Common Redshank (Tringa totanus) in the Demmerik polder, the Netherlands. One part of this polder, a nature reserve, has an older tree line, while two agricultural parts are divided by a newly developing tree line. As the tree line in the agricultural parts was developing, foraging families of Greylag Goose (Anser anser) showed a strong increase in only one of these parts during the breeding season. During the same period, the density of avian predators also increased in the whole polder. Analysis shows waders avoid trees in both situations: with an existing tree line (a static situation) and with a growing tree line (a dynamic situation). We investigated the possible role of geese and avian predators in explaining the decline in density of breeding wader meadow birds, by systematic comparison of several different models. In these models, the effect of the growing tree line has the greatest impact on breeding meadow birds. Models with geese describe the trends of breeding wader meadow birds better than those including avian predators, but since these two variables, geese and avian predators, are confounded, no definitive conclusion can yet be drawn. Potential explanations of and functional mechanisms behind the strong decline in breeding meadow bird populations in this area are discussed.

Migratory behavior can differ markedly amongst individuals within populations or species. Understanding the factors influencing this variation is key to understanding how current environmental changes might influence migratory propensity and the distribution and abundance of migratory species across their range. Here, we investigate variation in migratory behavior of the partially migratory Eurasian oystercatcher (Haematopus ostralegus) population breeding in Iceland. We use the resightings of color-ringed adults and stable isotopes to determine whether individuals migrate or remain in Iceland during winter and test whether individual migratory strategies vary in relation to sex, body size, and breeding location. We also explore individual consistency in migratory strategy and test whether assortative mating with respect to strategy occurs in this population. The proportion of migrants and residents varied greatly across breeding locations but not with respect to sex or body size. Individuals were consistent in migratory strategy between years and there was no evidence of assortative mating by migratory strategy. We use these findings to explore factors underlying the evolution and maintenance of partial migration at high latitudes.

SUMMARYThis study reviewed data from the Richmond River Area Pied Oystercatcher Protection Program 1997–2013 and Richmond River Area Shorebird Protection Program 2014–2018, on the far north coast of the State of New South Wales (NSW), Australia. The Australian Pied Oystercatcher Haematopus longirostris breeding population size for South Ballina Beach has decreased from 15–16 pairs in 1994–1996 to 7–9 pairs in 2016–2018. This is despite control of the European Red Fox Vulpes vulpes successfully reducing depredation of eggs and chicks and > 207 oystercatchers fledging from beaches in the Richmond River area in 1997–2018. The negative trend for South Ballina is contrasted with the positive trend for Bombing Range Beach, where the population size has increased from 4–5 pairs in 2002–2004 to 8–9 pairs in 2016–2018. Vehicle-based recreation has increased at South Ballina in the past two decades versus Bombing Range has remained closed to the public. It is proposed that human recreation disturbance is preventing recruitment into the South Ballina oystercatcher breeding population. Without strong protection of habitat from such disturbance, the NSW oystercatcher breeding population size is predicted to continue to decrease.

This is an integrative study of a potential zoonotic digenean from the Magellanic Southwestern Atlantic coast. The life cycle of the gymnophallid Gymnophalloides nacellae Cremonte, Pina, Gilardoni, Rodrigues, Chai and Ituarte, 2013 (Digenea) at the type locality, Puerto Deseado (47° 45′ S, 65° 51′ W), Santa Cruz province, was elucidated. This digenean uses the upper subtidal clam Gaimardia trapesina (Lamarck) (Gaimardiidae), which lives on the fronds of the giant kelp, as first intermediate host. A very short-stem furcocercous cercaria emerges and enters the limpets, Nacella magellanica (Gmelin) and N.deaurata (Gmelin) (Nacellidae), which live in the lower rocky intertidal zone. The unencysted metacercariae inhabit the extrapallial space of the limpet at high prevalences and intensities of infection. When the black oystercatcher Haematopus ater Vieillot and Oudart (Charadriidae) preys upon it, it becomes infected, acting as the definitive host. This parasite seems to exhibit a high specificity for their first and second intermediate hosts. Its geographical distribution is from 47 to 55° S in Patagonia, and it is restricted to those sites where the giant kelp reaches to lower intertidal and upper subtidal zones where the limpets are present. Gymnophalloides seoi Lee, Chai and Hong, 1993, a parasite of the Pacific oyster Magallana gigas (Thunberg) (Ostreidae), causes a zoonotic disease in Korea; thus, G. nacellae represent a risk of being a zoonotic parasite if infected limpets are consumed. Fil: Gilardoni, Carmen Mariangel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina Fil: Di Giorgio, Gisele Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina Fil: Bagnato, Estefanía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina Fil: Pina, Susana. Universidad de Porto; Portugal Fil: Rodrigues, Pedro. Universidad de Porto; Portugal. Institute for Molecular and Cell Biology (IBMC); Portugal Fil: Cremonte, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina

[Here we present the first report of Eurasian Oystercatcher nesting in the Province of Mantua; the nest was found on a sandbank on the Po river, in June 2017. This is the first case reported for the Po Valley away from the Adriatic coast]. [Article in Italian]

[Figure][1] A black oystercatcher ( Haematopus bachmani ), which feeds on limpets ( Lottia gigantea ). Photo credit: Dick Daniels ( ) CC BY-SA ( ) Recent reports make it clear that there are going to be many losers

Publiher's version (útgefin grein), Ground-nesting species are vulnerable to a wide range of predators and often experience very high levels of nest predation. Strategies to reduce nest vulnerability can include concealing nests in vegetation and/or nesting in locations in which nests and eggs are camouflaged and less easy for predators to locate. These strategies could have important implications for the distribution of ground-nesting species and the success rates of nests in areas with differing vegetation structure. However, the factors influencing the success of nest concealment and camouflage strategies in ground-nesting species are complex. Here we explore the effects of local vegetation structure and extent of nest concealment on nest predation rates in a range of ground-nesting, sympatric wader species with differing nest concealment strategies (open-nest species: Oystercatcher Haematopus ostralegus, Golden Plover Pluvialis apricaria and Whimbrel Numenius phaeopus; concealed-nest species: Black-tailed Godwit Limosa limosa, Redshank Tringa totanus and Snipe Gallinago gallinago) in south Iceland, in landscapes that comprise substantial variability in vegetation structure at a range of scales. We monitored 469 nests of these six wader species in 2015 and 2016 and ~40% of these nests were predated. Nest predation rates were similar for open-nest and concealed-nest species and did not vary with vegetation structure in the surrounding landscape, but nest-concealing species were ~10% more likely to have nests predated when they were poorly concealed, and the frequency of poorly concealed nests was higher in colder conditions at the start of the breeding season. For concealed-nest species, the reduced capacity to hide nests in colder conditions is likely to reflect low rates of vegetation growth in such conditions. The ongoing trend for warmer springs at subarctic latitudes could result in more rapid vegetation growth, with consequent increases in the success rates of early nests of concealed-nest species. Temperature-related effects on nest concealment from predators could thus be an important mechanism through which climate change affecting vegetation could have population-level impacts on breeding birds at higher latitudes., This work was supported by University of Iceland Research Fund, an Icelandic Research Council (Rannís) Grant (number 152470‐052), an NERC Grant (number NE/M012549/1), and FCT/MCTES to CESAM (UID/AMB/50017/2019) and individual grants to C.C. (PD/BD/113534/2015) and J.A.A. (SFRH/BPD/91527/2012) through national funds and ProPolar. The authors would like to thank Harry Ewing, Aldís Pálsdóttir, Catriona Morrison, Olivia Hicks, Mags Ramsey and Lilja Jóhannesdóttir for their assistance in the field, all iScreamers for fruitful discussions and the landowners who allowed access to their land for this study. We would like to thank Jeroen Reneerkens and three anonymous reviewers for their helpful comments on the manuscript.

SUMMARY Australian Pied Oystercatchers Haematopus longirostris and their habitat were surveyed on 72 beaches and 674 km of the SE Australian Coast, from Fraser Island, Queensland to near the New South Wales–Victoria state border and between 2015–2018. A grand total of 41 oystercatcher territories and 232 individual birds (the sum of mean beach counts) were counted. Bird-habitat models for oystercatcher mean count density indicated a positive response to the abundance of the primary prey species Donax deltoides, a large ‘surf clam’ and commonly known as the ‘pipi’, a negative response to the proportion of beach length urban and a negative S-N trend. Models for oystercatcher territory density indicated a positive response to pipi abundance and a negative response to pedestrian access density. This report upgrades the coastal development, tourism and human recreation disturbance threats for the species and calls for the long term protection of beach-nesting bird habitat.

The African Black Oystercatcher Haematopus moquini is a charismatic, southern African near-endemic, wader species, that is often seen as a flagship species for coastal bird conservation, as it was recently down-listed regionally to Least Concern on the IUCN Red List of Threatened Species. To celebrate this rare conservation success story, BirdLife South Africa named it the 2018 Bird of the Year and ran a year-long programme in collaboration with the Nature’s Valley Trust highlighting aspects of the species’ biology, current threats, and conservation success. We used data collected by the Southern African Bird Atlas Project (SABAP1 and SABAP2) to examine changes in the species’ range and relative abundance, both in the records between the two projects, as well as trends within the SABAP2 sampling period (2008–2017). This case study enabled us to assess whether such metrics can accurately reflect abundance and distributional changes in a species. We found increases in the reported range and the reporting rates between the two Atlas projects, and that the SABAP2 reporting rate was stable. Regionally, across four coastal categories, the reporting rate was lowest in KwaZulu-Natal, though this region also showed an increase in the probability of reporting during the SABAP2 period. While corroborating the recent change in the species’ conservation status, we also provide good evidence that the long-term SABAP data can be used successfully to assess population trends and range changes over time. Contrer la tendance: Les huîtriers pies noirs africains: un exemple de réussite récente en matière de conservationL’Huîtrier pie noir d’Afrique Haematopus moquini est une espèce charismatique quasi endémique d’Afrique australe, récemment classée dans la catégorie ‘menacée à moindre préoccupation,’ qui est souvent considérée comme une espèce phare pour la conservation des oiseaux côtiers. Pour célébrer cette rare réussite en matière de conservation, BirdLife South Africa l’a nommée ‘oiseau de l’année 2018’ et a mené un programme d’un an en collaboration avec le Nature’s Valley Trust, soulignant les aspects de la biologie de l’espèce, les menaces actuelles et le succès de la conservation. Sur la base de l’augmentation signalée de la taille de la population et de l’aire de répartition de l’espèce, nous utilisons les données recueillies dans le cadre des projets d’atlas des oiseaux d’Afrique australe (SABAP1 et SABAP2) afin d’examiner les modifications de l’aire de répartition et de l’abondance relative, au même titre que les tendances pour la période d’échantillonnage SABAP2 (2008–2017). Cela nous permet d’évaluer si ces paramètres peuvent indiquer avec précision de tels changements chez une espèce. Nous montrons que la portée et le taux de rapport ont augmenté entre les projets de l’atlas et que le taux de rapport pour SABAP2 est globalement stable. Au niveau régional, dans quatre groupes côtiers, le taux de rapport est le plus bas dans le KwaZulu-Natal, mais cette région montre également une augmentation de la probabilité de déclaration au cours de la période SABAP2. Tout en corroborant les changements récents dans l’état de conservation de l’espèce, le présent document fournit également de bonnes preuves que l’utilisation des données d’atlas à long-terme de SABAP peut être utilisée pour évaluer les tendances de la population et les modifications de l’aire de répartition dans le temps.Keywords: abundance, citizen science, Haematopus moquini, Red List Index, reporting rate, Southern African Bird Atlas Project

High temperatures resulting in physiological stress and the reduced ability to resist predation can have life-or-death consequences for an organism. We investigated the effects of temperature on the susceptibility to predation for an ectothermic intertidal mollusc (the owl limpet, Lottia gigantea Sowerby) and its predator, the black oystercatcher (Haematopus bachmani Audubon). The ability of L. gigantea to resist bird predation during low tide is determined by the tenacity of attachment to the rock. We developed a transducer to measure the force of predatory attacks on limpets by a captive black oystercatcher and tested the hypothesis that exposure to warm temperatures during low tide emersion would affect the limpet's ability to resist dislodgement in trials with a morphometrically accurate beak mimic and a live bird. In beak mimic trials, four times as many limpets exposed to warm low tides were removed, as compared to limpets exposed to cool low tides or in ‘no low tide’ submerged conditions. Minimum time before limpet removal in captive bird trials was more than six times longer for limpets in cool low tide or no low tide treatments compared to limpets in the warm low tide treatment. We measured shear forces up to 36.63 N during predatory strikes. These direct measurements of the forces exerted by a living oystercatcher provide context for interactions with multiple prey species. Our data suggest that naturally occurring variation in body temperatures among individual prey items in the field could be an important driver of predator-prey interactions and subsequently community patterns.

1. A combined empirical and modelling approach was used to investigate the value of a Pacific oyster reef to feeding shorebirds and to observe and predict the impact of reef clearance on bird populations in the Colne Estuary, a protected area in south‐east England. Macro‐invertebrate biomass and numbers of feeding birds were measured on a Pacific oyster reef, an adjacent uncolonized mudflat, and an area of mudflat that had been cleared of oysters 6 months previously. These data were used to parameterize an individual‐basedmodel (MORPH) to predict the impact of clearance of the reef on winter bird survival. Feeding success and intake rates of Eurasian oystercatcher, Eurasian curlew, and Eurasian common redshank were also recorded during the course of a winter. 2. Themacro‐invertebrate diversity and biomass within both the oyster reef and the cleared area were significantly greater than the adjacent uncolonized mudflat. The density and biomass of large invertebrate prey in the mudflat were low, yet the Pacific oyster reef hadmuch higher densities and biomass of large prey, especially annelids and shore crabs. 3. The winter assemblage of feeding birds differed significantly between each of the areas. The mean total number of feeding birds was significantly greater on the uncolonized mudflat; however, mean peak counts, feeding success rate and prey intake rate of Eurasian oystercatcher were greater on the reef. Significantly greater intake rates and feeding success rates were also observed on the reef for Eurasian curlew, a species of conservation concern. 4. Field data and model predictions show that Pacific oyster reefs can provide valuable supplementary feeding areas for some shorebirds, yet other species avoided the reef. However, as estuaries vary in available feeding resources, it is important that the value of reefs and their management is determined regionally.

Count data suggest that Black Oystercatcher (Haematopus bachmani) has locally variable but globally stable populations. A simple, stage-based matrix population model for Black Oystercatcher was built and Monte Carlo simulations of the model were conducted using vital rates from peer-reviewed and gray literature. Simulations yielded a distribution of potential population growth rates that extended from 0.87 to 1.14 and was centered at 1.00, supporting the hypothesis of a globally stable Black Oystercatcher population. Sensitivity and elasticity analyses of the population model showed that potential population growth is particularly sensitive to changes in hatching success (i.e., proportion of eggs hatched), fledging success (i.e., proportion of chicks fledged), and breeding adult annual survival. These rates could be possible targets for population management should it become necessary given future changes in sea temperature, sea level, and coastal development. Pair productivity, which integrates hatching and fledging success, is suggested as a simple and valuable metric for monitoring population growth potential of Black Oystercatcher.