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The current highly pathogenic avian influenza H5N1 panzootic is having substantial impacts on wild birds and marine mammals. Following major and widespread outbreaks in South America, an incursion to Antarctica occurred late in the austral summer of 2023/2024 and was confined to the region of the Antarctic Peninsula. To infer potential underlying processes, we compiled H5N1 surveillance data from Antarctica and sub-Antarctic Islands prior to the first confirmed cases., (© 2024 The Author(s). Influenza and Other Respiratory Viruses published by John Wiley & Sons Ltd.)

Ocean contamination, particularly from persistent organic pollutants (POPs), remains a significant threat to marine predators that occupy high trophic positions. Long-lived procellariform seabirds are apex predators in marine ecosystems and tend to accumulate contaminants. Prolonged exposure to pollutants negatively affects their fitness including reproductive success. Low breeding success may represent a hurdle for the restoration of small and endangered seabird populations, including several highly threatened gadfly petrels. Here we investigated the annual variation (2019 and 2022) in organochlorine pesticide (OCP), polychlorinated biphenyl ether (PCB), polybrominated diphenyl ether (PBDE), and polycyclic aromatic hydrocarbon (PAH) exposure in the endangered Bermuda petrel (Pterodroma cahow), and the relationship between female contaminant burden and breeding parameters. We found that petrels were exposed to a wide range of pollutants (33 out of 55 showed measurable levels) with PCBs dominating the blood contaminant profiles in both years. Only 9 compounds were detected in >50 % of the birds. Specifically, among OCPs, p, p'-DDE and hexaclorobenzene were the most frequently detected while fluorene and acenaphthene were the most common PAH. The concentrations of ∑ 5 PCBs and ∑ 7 POPs were higher in older birds. Furthermore, females with greater contaminant burdens laid eggs with a lower probability of hatching. However, female investment in egg production (size and volume) was unrelated to their blood contaminant load. Overall, this study highlights the presence of a wide range of contaminants in the petrel's food web, and it sheds light on the potential impact of chronic exposure to sub-lethal levels of PCBs on the breeding success of seabirds. We claim that toxicological testing should be a practice integrated in the management of seabirds, particularly of endangered species to monitor how past and present anthropogenic activities impact their conservation status., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The patterns of population divergence of mid-latitude marine birds are impacted by only a few biogeographic barriers to dispersal and the effect of intrinsic factors, such as fidelity to natal colonies or wintering grounds, may become more conspicuous. Here we describe, for the first time, the phylogeographic patterns and historical demography of Bulwer's petrel Bulweria bulwerii and provide new insights regarding the drivers of species diversification in the marine environment. We sampled Bulwer's petrels from the main breeding colonies and used a statistical phylogeography approach based on surveying nuclear and mitochondrial loci (~ 9100 bp) to study its mechanisms of global diversification. We uncovered three highly differentiated groups including the Western Pacific, the Central Pacific and the Atlantic. The older divergence occurred within the Pacific Ocean, ca. 850,000 ya, and since then the W Pacific group has been evolving in isolation. Conversely, divergence between the Central Pacific and Atlantic populations occurred within the last 200,000 years. While the Isthmus of Panama is important in restricting gene flow between oceans in Bulwer's petrels, the deepest phylogeographic break is within the Pacific Ocean, where oceanographic barriers are key in driving and maintaining the remarkable structure found in this highly mobile seabird. This is in contrast with the Atlantic, where no structure was detected. Further data will provide insights regarding the extent of lineage divergence of Bulwer's petrels in the Western Pacific., (© 2023. The Author(s).)

Static (fixed-boundary) protected areas are key ocean conservation strategies, and marine higher predator distribution data can play a leading role toward identifying areas for conservation action. The Falkland Islands are a globally significant site for colonial breeding marine higher predators (i.e., seabirds and pinnipeds). However, overlap between marine predators and Falkland Islands proposed Marine Managed Areas (MMAs) has not been quantified. Hence, to provide information required to make informed decisions regarding the implementation of proposed MMAs, our aims were to objectively assess how the proposed MMA network overlaps with contemporary estimates of marine predator distribution. We collated tracking data (1999-2019) and used a combination of kernel density estimation and model-based predictions of spatial usage to quantify overlap between colonial breeding marine predators and proposed Falkland Islands MMAs. We also identified potential IUCN Key Biodiversity Areas (pKBAs) using (1) kernel density based methods originally designed to identify Important Bird and Biodiversity Areas (IBAs) and (2) habitat preference models. The proposed inshore MMA, which extends three nautical miles from the Falkland Islands, overlapped extensively with areas used by colonial breeding marine predators. This reflects breeding colonies being distributed throughout the Falklands archipelago, and use being high adjacent to colonies due to central-place foraging constraints. Up to 45% of pKBAs identified via kernel density estimation were located within the proposed MMAs. In particular, the proposed Jason Islands Group MMA overlapped with pKBAs for three marine predator species, suggesting it is a KBA hot spot. However, tracking data coverage was incomplete, which biased pKBAs identified using kernel density methods, to colonies tracked. Moreover, delineation of pKBA boundaries were sensitive to the choice of smoothing parameter used in kernel density estimation. Delineation based on habitat model predictions for both sampled and unsampled colonies provided less biased estimates, and revealed 72% of the Falkland Islands Conservation Zone was likely a KBA. However, it may not be practical to consider such a large area for fixed-boundary management. In the context of wide-ranging marine predators, emerging approaches such as dynamic ocean management could complement static management frameworks such as MMAs, and provide protection at relevant spatiotemporal scales., (© 2021 by the Ecological Society of America.)

In their recent paper, Savoca and collaborators (2016) showed that plastic debris in the ocean may acquire a dimethyl sulfide (DMS) signature from biofouling developing on their surface. According to them, DMS emission may represent an olfactory trap for foraging seabirds, which explains patterns of plastic ingestion among procellariiform seabirds. This hypothesis is appealing, but some of the data that Savoca et al. used to support their claim are questionable, resulting in a misclassification of species, as well as other decisions regarding the variables to include in their models. Furthermore, with their focus on a single lifestyle trait (nesting habit) of dubious relevance for explaining plastic ingestion, Savoca et al. neglect the opportunity to explore other factors that might provide better ecological insight. Finally, we are deeply concerned by the conservation policy recommendation proposed by Savoca et al. -to increase antifouling properties of consumer plastics-which constitutes a substantial environmental risk and delivers the wrong message to decision-makers. The reduction of plastic consumption, waste prevention, and proactive reuse through a circular economy should be at the heart of policy recommendations for future mitigation efforts.

Knowledge of the dietary choices and trophic niches of organisms is the key to understanding their roles in ecosystems. In seabird diet studies, prey identification is a difficult challenge, often yielding results with technique-specific biases. Additionally, sampling efforts are often not extensive enough to reveal intrapopulational variation. Immature animals, which may constitute up to 50% of a population, may occupy a significantly different trophic niche to more experienced birds, but this remains largely unexplored. We investigated the diet of Cory's shearwater (Calonectris diomedea) from Selvagem Grande, an island located off the northwest African coast, collecting a total of 698 regurgitate samples over three consecutive breeding seasons. The diet was assessed using two complementary approaches for prey identification: conventional morphological analysis (using fish vertebrae, otoliths and cephalopod beaks) and DNA barcoding of the 16S rRNA mitochondrial gene, in cases where a positive identification could not be retrieved. Species assignments employed BLAST and distance-based methods, as well as direct optimization of the tree length based on unaligned sequences in POY. This method resulted in robust tree estimates and species assignments, showing its potential for DNA barcoding of stomach contents using hypervariable markers such as the 16S. The molecular approach increased taxonomic resolution and revealed an additional 17 taxa. Diet differed significantly according to breeding status, sex, breeding phase (prelaying and chick rearing) and year. Such direct evidence of trophic segregation within the same population has rarely been shown in seabirds and highlights the importance of including such variables in ecosystem-based management approaches., (© 2014 John Wiley & Sons Ltd.)

Carry-over effects relate to events or processes that influence individual performance in a subsequent season, but their occurrence in the annual cycle of migratory avian taxa is seldom studied. We investigated if different levels of resource allocation to reproduction may result in carry-over effects that change the timing and destination of long-distance migration. We reduced the parental investment of Cory's Shearwaters Calonectris diomedea by removing their chick at an early stage. When compared to individuals with greater parental investment (controls that raised chicks to close to fledging), manipulated birds started most stages of migration sooner and returned to the colony earlier at the start of the following breeding season. Late arrival in the subsequent nesting season increased the probability of skipping a breeding year. Manipulated males were less likely to engage in long-distance migration, which supports the idea that partial migration is condition dependent. Our study demonstrates experimentally that energetic or time-dependent costs of reproduction may have an enduring impact on migration schedule and on nonbreeding geographical distribution of long-distance migrants, which may also influence the ability to breed in the following season.

Long-distance migrants have developed diverse strategies to deal with the challenges imposed by their annual journeys. These are relatively well studied in some avian groups, such as passerines, shorebirds and raptors. In contrast, few studies have addressed the migratory behaviour of pelagic birds in the light of current theories of optimal migration. Using a dataset of 100 complete migratory tracks gathered along four years, we performed a detailed study on the migratory strategy of a pelagic trans-equatorial migrant, the Cory's shearwater Calonectris diomedea. We analysed daily routines, stopover ecology and travel speed, as well as the influence of the moon on several behavioural patterns. Cory's shearwaters adopted a "fly-and-forage" strategy when migrating, similarly to what has been observed in some raptors. However, by flying by dynamic soaring, shearwaters attained high overall migration speeds, and were able to travel thousands of kilometres without making major stopovers and, apparently, without a noticeable pre-migratory fattening period. Other major findings of this study include the ability to adapt daily schedules when crossing major ecological barriers, and the constant adjustment of migration speed implying higher rates of travel in the pre-breeding movement, with a final sprint to the nesting colony. The present study also highlights a preference of Cory's shearwaters for starting travel at twilight and documents a strong relationship between their migratory activity and the moon phase.

There is growing evidence that migratory species are particularly vulnerable to rapid environmental changes arising from human activity. Species are expected to vary in their capacity to respond to these changes: long-distance migrants and those lacking variability in migratory traits are probably at considerable disadvantage. The few studies that have assessed the degree of plasticity in behaviour of marine animals suggest that fidelity to non-breeding destinations is usually high. In the present study, we evaluated individual flexibility in migration strategy of a highly pelagic seabird, the Cory's shearwater Calonectris diomedea. Geolocation data from 72 different migrations, including 14 birds that were tracked for more than one non-breeding season, showed a remarkable capacity to change winter destinations between years. Although some birds exhibited high site fidelity, others shifted from the South to North Atlantic, from the western to eastern South Atlantic, and from the Atlantic to Indian Ocean. Individuals also showed flexibility in stopover behaviour and migratory schedule. Although their K-selected life-history strategy has the disadvantage that the chances of microevolution are slight if circumstances alter rapidly, these results suggest that Cory's shearwaters may be in a better position than many other long-distance migrants to face the consequences of a changing environment.

Fisheries have major impacts on seabirds, both by changing food availability and by causing direct mortality of birds during trawling and longline setting. However, little is known about the nature and the spatial-temporal extent of the interactions between individual birds and vessels. By studying a system in which we had fine-scale data on bird movements and activity, and near real-time information on vessel distribution, we provide new insights on the association of a threatened albatross with fisheries. During early chick-rearing, black-browed albatrosses Thalassarche melanophris from two different colonies (separated by only 75 km) showed significant differences in the degree of association with fisheries, despite being nearly equidistant to the Falklands fishing fleet. Most foraging trips from either colony did not bring tracked individuals close to vessels, and proportionally little time and foraging effort was spent near ships. Nevertheless, a few individuals repeatedly visited fishing vessels, which may indicate they specialise on fisheries-linked food sources and so are potentially more vulnerable to bycatch. The evidence suggests that this population has little reliance on fisheries discards at a critical stage of its nesting cycle, and hence measures to limit fisheries waste on the Patagonian shelf that also reduce vessel attractiveness and the risk of incidental mortality, would be of high overall conservation benefit.

Plastic pollution is distributed patchily around the worlds oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are highly threatened, and cover vast distances during foraging and migration. However, the spatial overlap between petrels and plastics is poorly understood. Here we combine marine plastic density estimates with individual movement data for 7137 birds of 77 petrel species to estimate relative exposure risk. We identify high exposure risk areas in the Mediterranean and Black seas, and the northeast Pacific, northwest Pacific, South Atlantic and southwest Indian oceans. Plastic exposure risk varies greatly among species and populations, and between breeding and non-breeding seasons. Exposure risk is disproportionately high for Threatened species. Outside the Mediterranean and Black seas, exposure risk is highest in the high seas and Exclusive Economic Zones (EEZs) of the USA, Japan, and the UK. Birds generally had higher plastic exposure risk outside the EEZ of the country where they breed. We identify conservation and research priorities, and highlight that international collaboration is key to addressing the impacts of marine plastic on wide-ranging species.

Microplastics are widespread in aquatic environments and can be ingested by a wide range of organisms. They can also be transferred along food webs. Estuaries and other tidal wetlands may be particularly prone to this type of pollution due to their particular hydrological characteristics and sewage input, but few studies have compared wetlands with different anthropogenic pressure. Furthermore, there is no information on microplastic transfer to secondary intertidal consumers such as shorebirds. We analysed intertidal sediments, macroinvertebrates and shorebirds, from three important wetlands along the Eastern Atlantic (Tejo estuary, Portugal; Banc d’Arguin, Mauritania and Bijagós archipelago, Guinea-Bissau), in order to evaluate the prevalence and transfer of microplastics along the intertidal food web. We further investigated variables that could explain the distribution of microplastics within the intertidal areas of the Tejo estuary. Microfibers were recorded in a large proportion of sediment samples (91%), macroinvertebrates (60%) and shorebird faeces (49%). μ-FTIR analysis indicated only 52% of these microfibers were composed of synthetic polymers (i.e. plastics). Microfiber concentrations were generally higher in the Tejo and lower in the Bijagós, with intermediate values for Banc d’Arguin, thus following a latitudinal gradient. Heavier anthropogenic pressure in the Tejo explains this pattern, but the relatively high concentrations in a pristine site like the Banc d’Arguin demonstrate the spread of pollution in the oceans. Similar microfiber concentrations in faeces of shorebirds with different foraging behaviour and similar composition of fibres collected from invertebrate and faeces suggest shorebirds mainly ingest microfibers through their prey, confirming microfiber transfer along intertidal food webs. Within the Tejo estuary, concentration of microfibers in the sediment and bivalves were positively related with the percentage of fine sediments and with the population size of the closest township, suggesting that hydrodynamics and local domestic sewage are the main factors influencing the distribution of microfibers. [ABSTRACT FROM AUTHOR]

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Abstract: Estuarine sediment flats are essential feeding areas for waders, but their exploitation is constrained by the movements of tides. In this cyclic environment the exposure period of sediment flats decreases several fold from upper to lower flats, and the moving tidal waterline briefly creates particular conditions for waders and their prey. This study attempts to determine how the exposure period and the movement of the tide line influence the use of space and food resources by waders across the sediment flats. Wader counts and observations of feeding behaviour were carried out in all phases of the tidal cycle, in plots forming a transect from upper to lower flats, thus representing a gradient of exposure periods. Pecking, prey intake, and success rates varied little along the gradient. Some species actively followed the tide line while foraging, whereas others are evenly spread over the exposed flats. Black-tailed Godwit, Dunlin and Avocet were ''tide followers'', whereas Grey Plover, Redshank and Bar-tailed Godwit were ''non-followers''. Densities of ''followers'' near the tide line were up to five times higher than elsewhere. Species differed markedly in the way they used space on the flats, but in general the rate of biomass acquisition (in grams of ash-free dry weight per time exposed) was much higher in lower flats. However, this preference was insufficient to counter the much longer exposure of the upper flats, so the total amount of biomass consumed on the latter was greater. Therefore, it was in these upper flats that waders fulfilled most of their energetic needs. Consequently, upper flats are of particular importance for the conservation of wader assemblages, but because they are usually closer to shore they tend to suffer the highest pressure from disturbance and land reclamation. [Copyright &y& Elsevier]

Abstract: Montados are Mediterranean agro-forestry-pastoral systems recognized as an excellent example of balance between socio-economic development and biodiversity conservation. The economic viability of montados dominated by cork oak Quercus suber depends on the extraction of cork (the bark of trees), usually in 9year cycles, which is mostly used for production of bottle stoppers. This study evaluated the impact of cork extraction on biodiversity, using birds as indicators. Comparing bird assemblages of areas with recently extracted cork and older cork revealed that only two species of bark gleaners and two of bark-foliage gleaners had lower densities in recently debarked areas. Arthropod sampling revealed that, in the first years after cork extraction, the bark has less prey, suggesting that the reduction in bark gleaners densities is a result of the decreased food availability. Focal observations confirmed that the affected species were those that foraged mostly on cork. However, our data demonstrated that bird richness and the density of the majority of species were unaffected by debarking, and that at the landscape level even bark gleaners had potentially stable populations. Pressure from the synthetic bottle stopper industry threatens to render montados economically unviable, and consequently be replaced by land uses much less valuable for biodiversity. Showing that cork extraction is compatible with the maintenance of the great ornithological value of montados, our results confirm that it is an economic activity that should be promoted for the benefit of biodiversity. [Copyright &y& Elsevier]