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With coastal wader populations exhibiting long-term declines globally, understanding how they respond to changes in their preferred prey is important for future predictions, especially given the potential for warming seas to affect invertebrate populations. The cockle Cerastoderma edule population in the Burry Inlet Special Protection Area (SPA) in south Wales, UK, declined from 1997-2004 before an abrupt ‘crash’ in stocks between 2004 and 2010. While there has been some recovery since, stocks of larger cockles are still very low. Using survey data from the UK Wetland Bird Survey and analyses of apparent survival and biometrics from ringing, we investigated how the Burry Inlet SPA’s wintering Eurasian oystercatcher Haematopus ostralegus population responded to this crash. Our analysis showed that both body condition and apparent survival of wintering adult oystercatchers were reduced in the years following the cockle crash but both recovered. The number of birds using the Burry Inlet SPA decreased through the course of the cockle stock decline whilst numbers of birds in the adjacent Carmarthen Bay increased, indicating the importance of adjacent sites for buffering the effects of such changes, i.e. protected secondary habitats can be a vital component of a resilient site network. Our findings are useful in understanding how a predator copes with a serious decline in its preferred food stocks. This study has wide applicability in planning the management of coastal wetlands and shellfisheries as well as the design of resilient protected area networks in the light of environmental change.

Tracking tags have been used to map the distributions of a wide variety of avian species, but few studies have examined whether the use of these devices has impacts on the study animals that may bias the spatial data obtained. As Global Positioning System (GPS) tags small enough for deployment on terns (family: Laridae) have only recently become available, until now tracking of this group has been conducted by following unmanipulated individuals by boat, which offers a means of comparing distributions obtained from GPS‐tracking. We compared the utilization distributions (UDs) of breeding Arctic Terns Sterna paradisaea obtained by GPS‐tracking 10 individuals over 2 weeks, with UDs derived from contemporaneous visual boat tracks from 81 individuals. The 50% and 95% UDs of both methods had high similarity scores, indicating good agreement in the density distributions derived from the two methods. The footprints of the UDs of tagged birds were ~ 75–80% larger, which may reflect an effect of tagging on foraging range or the occasional inability to follow by boat individuals which roamed further from the colony. We also compared the nest attendance and chick provisioning rates of adults that were (1) fitted with a GPS tag and leg‐flag, (2) handled and marked with a leg‐flag but not tagged and (3) fitted with a leg‐flag in a previous year but unhandled in the year of the study. There was some evidence that birds fitted with both a GPS tag and leg‐flag spent slightly less time at the nest compared with unhandled birds and those fitted with a leg‐flag only. Both treatments where birds were fitted with a leg‐flag in the year of the study had similarly lower provisioning rates to those of unhandled control birds > 48 h after handling, suggesting that negative effects on provisioning are due to capture and handling or leg‐flag attachment rather than to GPS tag attachment/loading per se. Overall brood‐provisioning rate was compensated for by the increased effort by the unhandled partner. Our study suggests that despite slight effects of GPS‐tagging on behaviour, the estimates of marine density distribution obtained were very similar to those of unmanipulated birds.

Publisher Copyright: © 2022 British Ecological Society. An increasing number of species are facing unprecedented levels of threat to their long-term survival due to the direct and indirect impacts of climate change. Key opportunities for science to inform wildlife management are linked to increasing our understanding of how changes in climatic conditions will impact species, as well as whether, and how, managers may facilitate species' ability to adapt to change. However, information on species' climate change vulnerability and the effectiveness of potential conservation actions are not yet strategically collected or collated; this disconnect between threat level, ecological research and conservation practice is reducing the opportunities to guide decision-making, ultimately hindering conservation outcomes. To demonstrate this point, we explore how existing knowledge can be brought together in a pressure-state-response framework that connects climate change ecology, conservation evidence assessments and management. Seabirds in Western Europe are used as a case study, as they are well-researched and vulnerable to climate change. Using a combination of literature reviews and surveys, we identify the main threats posed to seabirds in the region by climate change, as well as existing conservation actions that could be applied to lessen the impacts of each of these threats. Our results show that 29% of the types of actions considered for reducing the impacts of climate change on seabirds are either associated with conflicting evidence or lack sufficient information to make robust conclusions about their effectiveness: actions aiming at restoring or creating habitat, encouraging relocation, treating or preventing disease, and reducing inter-species competition all have limited or mixed evidence to support their use. Moreover, several threats identified by conservation practitioners as being of high priority to address, such as changes in prey abundance and eutrophication, have few or no viable identified actions to reduce their impact on seabirds. Synthesis and applications. We suggest that existing knowledge on species vulnerability to climate change and evidence of conservation action effectiveness should be more commonly brought together in tailored pressure-state-response frameworks. Such an approach provides an easily transferable platform for identifying missing information and areas where connections between research and management need to be tightened to improve conservation outcomes.

Identifying the breeding status of cryptic bird species has proved problematic without intense or inherently expensive monitoring. Most, if not all, intensive bird monitoring comes with disturbance risks and many projects now rely on tagging of individuals to provide remote information on movements. Given the importance of breeding status when targeting conservation interventions novel methods are needed. This study aimed to identify breeding status in Eurasian Curlew (

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.

Extrinsic mortality has a strong impact on the evolution of life-histories, prey morphology and behavioural adaptations, but for many animals the causes of mortality are poorly understood. Predation is an important driver of extrinsic mortality and mobile animals form groups in response to increased predation risk. Furthermore, in many species juveniles suffer higher mortality than older individuals, which may reflect a lower phenotypic quality, lower competitiveness, or a lack of antipredator or foraging skills. Here we assessed the causes of mortality for 371 radio tagged Siberian jays. This sedentary bird species lives in family groups that contain a breeding pair as well as related and unrelated non-breeders. Ninety-five percent of death were due to predation (n = 59 out of 62 individuals) and most individuals were killed by Accipiter hawks. Multivariate Cox proportional hazards models showed that non-breeders had a lower survival than breeders, but only in territories in managed forest with little visual cover. Examining breeders, only sex influenced survival with males having a lower survival than females. For non-breeders, juveniles had lower survival than older non-breeders, and those on managed territories had lower survival than those on unmanaged territories. Additionally, a low feather quality reduced the survival probability of non-breeders only. Thus, living on managed territories and having a low feature quality affected only non-breeders, particularly juveniles. These findings add to previous research demonstrating that juvenile Siberian jays acquire critical antipredator skills from experienced group members. Thus, experience can buffer extrinsic mortality, highlighting that group living not only provides safety in numbers, but also provide social opportunities to learn critical life-skills.

Regime shifts in benthic invertebrates within coastal ecosystems threaten the survival of wading birds (Charadrii). Predicting how invertebrate regime shifts will affect wading birds allows conservation management and mitigation measures to be implemented, including protection of terrestrial feeding areas. An individual-based model was used to investigate the impact of regime shifts on wading birds through their prey (marine worms and bivalves) in the estuarine system Poole Harbour, (UK). The model predicted the number of curlew (Numenius arquata), oystercatcher (Haematopus ostralegus), black-tailed godwit (Limosa limosa), redshank (Tringa totanus) and dunlin (Calidris alpina) supported in the Harbour during the non-breeding season (autumn and winter months). The most dramatic declines in bird numbers were for regime shifts that reduced the abundance of the largest invertebrates, particularly marine worms. The least adaptable bird species (those with the most restrictive diets) were unable to compensate by consuming other prey. Generally, as birds adapt to changes by switching to alternative prey species and size classes, changes in invertebrate size and species distribution do not necessarily affect the number of birds that the Harbour can support. Our predictions reveal a weakness in using birds as indicators of site health and invertebrate regime shifts. Differences in bird populations would not necessarily be detected by standard survey methods until extreme changes in invertebrate communities had occurred, potentially beyond the point at which these changes could be reversed. Therefore, population size of wading birds should not be used in isolation when assessing the conservation status of coastal sites.