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Pelagic seabirds are amongst the most threatened of all avian groups. They face a range of immunological challenges which seem destined to increase due to environmental changes in their breeding and foraging habitats, affecting prey resources and exposure to pollution and pathogens. Therefore, the identification of biomarkers for the assessment of their health status is of considerable importance. Peptidylarginine deiminases (PADs) post-translationally convert arginine into citrulline in target proteins in an irreversible manner. PAD-mediated deimination can cause structural and functional changes in target proteins, allowing for protein moonlighting in physiological and pathophysiological processes. PADs furthermore contribute to the release of extracellular vesicles (EVs), which play important roles in cellular communication. In the present study, post-translationally deiminated protein and EV profiles of plasma were assessed in eight seabird species from the Antarctic, representing two avian orders: Procellariiformes (albatrosses and petrels) and Charadriiformes (waders, auks, gulls and skuas). We report some differences between the species assessed, with the narrowest EV profiles of 50–200 nm in the northern giant petrel Macronectes halli, and the highest abundance of larger 250–500 nm EVs in the brown skua Stercorarius antarcticus. The seabird EVs were positive for phylogenetically conserved EV markers and showed characteristic EV morphology. Post-translational deimination was identified in a range of key plasma proteins critical for immune response and metabolic pathways in three of the bird species under study; the wandering albatross Diomedea exulans, south polar skua Stercorarius maccormicki and northern giant petrel. Some differences in Gene Ontology (GO) biological and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways for deiminated proteins were observed between these three species. This indicates that target proteins for deimination may differ, potentially contributing to a range of physiological functions relating to metabolism and immune response, as well as to key defence mechanisms. PAD protein homologues were identified in the seabird plasma by Western blotting via cross-reaction with human PAD antibodies, at an expected 75 kDa size. This is the first study to profile EVs and to identify deiminated proteins as putative novel plasma biomarkers in Antarctic seabirds. These biomarkers may be further refined to become useful indicators of physiological and immunological status in seabirds—many of which are globally threatened.

1. Age-related variation in reproductive performance is ubiquitous in wild vertebrate populations and has important consequences for population and evolutionary dynamics. 2. The ageing trajectory is shaped by both within-individual processes, such as improvement and senescence, and the among-individual effects of selective appearance and disappearance. To date, few studies have compared the role of these different drivers among species or populations. 3. In this study, we use nearly 40 years of longitudinal monitoring data to contrast the within- and among-individual processes contributing to the reproductive ageing patterns in three albatross species (two biennial and one annual breeder) and test whether these can be explained by differences in life histories. 4. Early-life performance in all species increased with age and was predominantly influenced by within-individual improvements. However, reproductive senescence was detected in only two of the species. In the species exhibiting senescent declines, we also detected a terminal improvement in breeding success. This is suggestive of a trade-off between reproduction and survival, which was supported by evidence of selective disappearance of good breeders. 5. We demonstrate that comparisons of closely related species which differ in specific aspects of their life history can shed light on the ecological and evolutionary forces shaping variation in ageing patterns.

Invasive rodents threaten native species in numerous ecosystems, especially oceanic islands. The House Mouse Mus musculus is the only introduced mammal species on sub-Antarctic Gough and Marion Islands. Ample evidence exists of mice preying upon seabird chicks on these two islands, but there have been only a few reports of attacks on adult seabirds, none of which has been fatal. We report the first deaths of adult great albatrosses due to mouse attacks. On Gough Island, three Tristan Albatrosses Diomedea dabbenena (Critically Endangered) brooding small chicks were observed with wounds typical of mouse attacks in March–April 2021; two likely abandoned their chick, causing breeding failure, and the third was found dead eight days after discovery with large blowfly larvae in the wound. On Marion Island, two wounded and eight dead adult Wandering Albatrosses D. exulans (Vulnerable) were found in April 2023. Inspection of the wounded individuals, as well as the injuries on the fresh carcasses strongly suggest that mouse predation was the cause of death. Gough Island is home to virtually all Tristan Albatrosses, and Marion Island is the single most important breeding site for Wandering Albatrosses, home to about a quarter of all breeding birds. The death of breeding adults of these long-lived species emphasizes the urgent need to eradicate introduced mice from these islands.

Many animals form long‐term monogamous pair‐bonds, and the disruption of a pair‐bond (through either divorce or widowhood) can have significant consequences for individual vital rates (survival, breeding, and breeding success probabilities) and life‐history outcomes (lifetime reproductive success, life expectancy). Here, we investigated the causes and consequences of pair‐bond disruption in wandering albatross (Diomedea exulans). State‐of‐the‐art statistical and mathematical approaches were developed to estimate divorce and widowhood rates and their impacts on vital rates and life‐history outcomes. In this population, females incur a higher mortality rate due to incidental fishery bycatch, hence the population is male‐skewed. Therefore, we first posited that males show higher widowhood rates negatively correlated with fishing effort, and females have higher divorce rates because they have more mating opportunities. Furthermore, we expected that divorce can be an adaptive strategy, whereby individuals improve breeding success by breeding with a new partner of better quality. Finally, we posited that pair‐bond disruptions can reduce survival and breeding probabilities due to the cost of remating processes, with important consequences for life‐history outcomes. As expected, we show that males have higher widowhood rates than females and females have higher divorce rates in this male‐skewed population. However, no correlation was found between fishing effort and male widowhood. Secondly, contrary to our expectation, we found that divorce is likely non‐adaptive in this population. We propose that divorce in this population is caused by an intruder who outcompetes the original partner in line with the “forced divorce” hypothesis. Furthermore, we found a 16.7% and 18.0% reduction in lifetime reproductive success (LRS) only for divorced and widowed males, respectively, due to missing breeding seasons after a pair‐bond disruption. Finally, we found that divorced individuals are more likely to divorce again, but whether this is related to specific individual characteristics remains an important area of investigation.

Petrels, albatrosses, and storm-petrels are among the most beautiful yet least known of all the world's birds, living their lives at sea far from the sight of most people. Largely colored in shades of gray, black, and white, these enigmatic and fast-flying seabirds can be hard to differentiate, particularly from a moving boat. Useful worldwide, not just in North America, this photographic guide is based on unrivaled field experience and combines insightful text and hundreds of full-color images to help you identify these remarkable birds. The first book of its kind, this guide features an introduction that explains ocean habitats and the latest developments in taxonomy. Detailed species accounts describe key identification features such as flight manner, plumage variation related to age and molt, seasonal occurrence patterns, and migration routes. Species accounts are arranged into groups helpful for field identification, and an overview of unique identification challenges is provided for each group. The guide also includes distribution maps for regularly occurring species as well as a bibliography, glossary, and appendixes. The first state-of-the-art photographic guide to these enigmatic seabirdsIncludes hundreds of full-color photos throughoutFeatures detailed species accounts that describe flight, plumage, distribution, and moreProvides overviews of ocean habitats, taxonomy, and conservationOffers tips on how to observe and identify birds at sea

1. Our understanding of demographic processes is mainly based on analyses of traits fromthe adult component of populations. Early-life demographic traits are poorly known mainlyfor methodological reasons. Yet, survival of juvenile and immature individuals is critical forthe recruitment into the population and thus for the whole population dynamic, especially forlong-lived species. This bias currently restrains our ability to fully understand populationdynamics of long-lived species and life-history theory.2. The goal of this study was to estimate the early-life demographic parameters of a longlivedspecies with a long immature period (9–10 years), to test for sex and age effects on theseparameters and to identify the environmental factors encountered during the period of immaturitythat may influence survival and recruitment.3. Using capture–mark–recapture multievent models allowing us to deal with uncertain andunobservable individual states, we analysed a long-term data set of wandering albatrosses toestimate both age- and sex-specific early-life survival and recruitment. We investigated environmentalfactors potentially driving these demographic traits using climatic and fisheries covariatesand tested for density dependence.4. Our study provides for the first time an estimate of annual survival during the first 2 yearsat sea for an albatross species (0801 0014). Both age and sex affected early-life survivaland recruitment processes of this long-lived seabird species. Early-life survival and recruitmentwere highly variable across years although the sensitivity of young birds to environmental variabilitydecreased with age. Early-life survival was negatively associated with sea surface temperature,and recruitment rate was positively related to both Southern Annular Mode and seasurface temperature. We found strong evidence for density-dependent mortality of juveniles.Population size explained 41% of the variation of this parameter over the study period.5. These results indicate that early-life survival and recruitment were strongly age and sexdependent in a dimorphic long-lived species. In addition, early-life demographic parameterswere affected by natal environmental conditions and by environmental conditions faced duringthe period of immaturity. Finally, our results constitute one of the first demonstrations ofdensity dependence on juvenile survival in seabirds, with major consequences for our understandingof population dynamics in seabirds.

Although age at first reproduction is a key demographic parameter which is probably under high selective pressure, it is highly variable and the cause of this variability is not well understood. Two non-exclusive hypotheses may explain such variability. It could be the expression of different individual strategies, i.e. different allocation strategies in fitness components, or the consequences of individual difference in intrinsic quality, i.e. some individuals always doing better than others in all fitness components. We tested these hypotheses in the Wandering albatross investigating relationships between the age at first reproduction and subsequent adult demographic traits. Using finite mixture capture recapture modeling, we demonstrate that the age at first reproduction is negatively related to both reproductive performances and adult survival, suggesting that individual quality was an important factor explaining variation in the age at first reproduction. Our results suggest that age at first breeding is a good predictor of quality in this long-lived seabird species.

The relationship between the environment and marine animal small-scale behavior is not fully understood. This is largely due to the difficulty in obtaining environmental datasets with a high spatiotemporal precision. The problem is particularly pertinent in assessing the influence of environmental factors in rapid, high energy-consuming behavior such as seabird takeoff. To fill the gaps in the existing environmental datasets, we employed novel techniques using animal-borne sensors with motion records to estimate wind and ocean wave parameters and evaluated their influence on wandering albatross takeoff patterns. Measurements revealed that wind speed and wave heights experienced by wandering albatrosses during takeoff ranged from 0.7 to 15.4 m/s and 1.6 to 6.4 m, respectively. The four indices measured (flapping number, frequency, sea surface running speed, and duration) also varied with the environmental conditions (e.g., flapping number varied from 0 to over 20). Importantly, takeoff was easier under higher wave conditions than under lower wave conditions at a constant wind speed, and takeoff effort increased only when both wind and waves were gentle. Our data suggest that both ocean waves and winds play important roles for albatross takeoff and advances our current understanding of albatross flight mechanisms. eLife assessment This fundamental study advances our understanding of seabird responses to environmental conditions, with implications for movement ecology, flight biomechanics, animal foraging, and bioenergetics. Animal-borne data-loggers are used to generate a compelling high quality dataset on animal movement and environmental conditions. The study will interest ornithologists, comparative bio-mechanists, ocean ecologists and those interested in technological advances in animal sensors.

Many wildlife species inhabit inaccessible environments, limiting researchers ability to conduct essential population surveys. Recently, very high resolution (sub-metre) satellite imagery has enabled remote monitoring of certain species directly from space; however, manual analysis of the imagery is time-consuming, expensive and subjective. State-of-the-art deep learning approaches can automate this process; however, often image datasets are small, and uncertainty in ground truth labels can affect supervised training schemes and the interpretation of errors. In this paper, we investigate these challenges by conducting both manual and automated counts of nesting Wandering Albatrosses on four separate islands, captured by the 31 cm resolution WorldView-3 sensor. We collect counts from six observers, and train a convolutional neural network (U-Net) using leave-one-island-out cross-validation and different combinations of ground truth labels. We show that (1) interobserver variation in manual counts is significant and differs between the four islands, (2) the small dataset can limit the networks ability to generalise to unseen imagery and (3) the choice of ground truth labels can have a significant impact on our assessment of network performance. Our final results show the network detects albatrosses as accurately as human observers for two of the islands, while in the other two misclassifications are largely caused by the presence of noise, cloud cover and habitat, which was not present in the training dataset. While the results show promise, we stress the importance of considering these factors for any study where data is limited and observer confidence is variable.

Parental investment increases offspring fitness at the expense of the parent's ability to invest in other offspring. In many animal species, parents guard their offspring after birth. The parental decision over the duration of this period is expected to be triggered by the associated fitness costs and benefits for both offspring and parents.