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1AbstractIndividuals differ in many ways. Most produce few offspring; a handful produce many. Some die early; others live to old age. It is tempting to attribute these differences in out-comes to differences in individual traits, and thus in the demographic rates experienced. However, there is more to individual variation than meets the eye of the biologist. Even among individuals sharing identical traits, life history outcomes will vary due to individual stochasticity, i.e., to chance. Quantifying the contributions of heterogeneity and chance is essential to understanding natural variability. Inter-individual differences vary across environmental conditions. Heterogeneity and stochasticity depend on environmental conditions. We show that favorable conditions increase the contributions of individual stochasticity, and reduce the contributions of heterogeneity, to variance in demographic outcomes in a seabird population. The opposite is true under poor conditions. This result has important consequence for understanding the ecology and evolution of life history strategies.

Seabirds often spend time on the water in the vicinity of their breeding colonies at the start or end of foraging trips, which may be for bathing, social interaction, information transfer, or to reduce predation risk for small petrels that prefer to return to land in darkness. Although such behaviour (hereafter rafting) is common, there are few data on variation in its incidence or timing across species, or analyses of relationships with intrinsic or extrinsic factors such as breeding stage (reflecting central-place foraging constraints) or weather. Here, we use GPS and immersion data collected over multiple years at Bird Island, South Georgia, to investigate rafting behaviour of four albatross and one burrow-nesting petrel species. Nearly all tracked birds (89%) landed within 10 km of the colony at the start of foraging trips for ~ 30 min, whereas only 17% did so at the end, suggesting they likely use rafting mainly for plumage maintenance after extended breeding shifts on land. Rafting duration, distance and bearing from the colony varied markedly according to species, wind speeds and period of the day (daylight vs. darkness), which may reflect differences in foraging direction, time constraints, degree of plumage soiling, diel activity patterns, or the requirement for high wind speeds for efficient flight. Given that all the study populations are decreasing, and most individuals make extensive use of nearshore waters during the breeding season, effective marine spatial planning is required that eliminates or mitigates human risks around their colonies.

Puffinosis is a disease of a range of seabirds characterised by dorsal and ventral blistering of their webbed feet, conjunctivitis, dry necrosis, leg spasticity, head shaking, loss of balance, tremors, and death. It is associated with Manx shearwaters (Puffinus puffinus), frequently affecting chicks within their underground nesting burrows. The aetiology of the disease is unclear but has been attributed to a type-2 coronavirus associated with Neotombicula mites as a potential vector. However, there is some uncertainty given potential laboratory contamination with mouse hepatitis virus and failure to fulfil Koch’s postulates, with birds injected with isolates remaining healthy. We describe a detailed case report of puffinosis in a Manx Shearwater covering necropsy, histology, bacteriology, and metagenomics including viral sequencing. We found no evidence of viral infection or parasites. Our results are consistent with an entirely environmental aetiology, with caustic faecal ammonia in damp nesting burrows causing conjunctivitis and foot dermatitis breaking the skin, allowing common soil bacteria (i.e., Flavobacterium, Staphylococcus and Serratia spp., Clostridia perfringens and Enterococcus faecalis) to cause opportunistic infection, debilitating the bird and leading to death. A similar condition (foot pad dermatitis or FPD) has been reported in broiler chickens, attributed to caustic faeces, high humidity, and poor environmental conditions during indoor rearing, preventable by adequate ventilation and husbandry. This is consistent with puffinosis being observed in Shearwater nesting burrows situated in tall, dense, vegetation (e.g., bracken Pteridium aquilinum) but rarely reported in burrows situated in well-ventilated, short coastal grasslands. This proposed environmental aetiology accounts for the disease’s non-epizootic prevalence, spatial variation within colonies, and higher frequency in chicks that are restricted to nesting burrows.

In the present study, mercury (Hg), cadmium (Cd), lead (Pb), selenium (Se), and arsenic (As) were measured in liver, kidney, and feathers of adult, juvenile, and chick seagulls (Larus michahellis) collected from the northwest of Spain. Age, sex, and the geographical location of samples were considered variables that can influence metal bioaccumulation, for which concentrations were determined by means of ICP-MS. The mean concentrations (dry weight) found in seagulls were 7.01 ± 0.37 mg Hg/kg, 22.82 ± 2.83 mg Cd/kg, 7.36 ± 1.36 mg Pb/kg, 18.64 ± 0.63 mg Se/kg, and 10.64 ± 0.59 mg As/kg. Regarding the different factors analyzed, Hg was the only metal showing sex-related differences, being significantly higher (p p p p p p L. michahellis can reveal local contamination around the foraging and breeding sites and can be a very useful monitoring instrument for assessing heavy metal contamination and sentinel species of environmental health.

Petrels are particularly sensitive to predation by introduced species. Many populations have reduced their breeding ranges, currently mainly occupying predator-free sites. Breeding range reduction leads to interspecific competition for nesting sites, which can be detrimental to petrels. Here, we evaluate how the presence of introduced mammals (cats Felis catus and rats Rattus spp.) and potential competitors for nest sites (Cory’s shearwaters Calonectris borealis and feral rock pigeons Columba livia) shape the distribution, breeding density, and breeding performance of Bulwer’s petrel Bulweria bulwerii on Tenerife, the largest and most densely human populated of the Canary Islands. We estimated nest density, assessed the role of nest location and physical characteristics of nests on breeding success, and determined causes of breeding failure by introduced predators and competitors. Nest density was higher in predator-free colonies on marine rocks. Cat presence was the best predictor of nest density, but it was not correlated with either presence or abundance of competitors. Breeding success varied between years and colonies but was not related to nest characteristics. Pigeon competition for nests was the most frequent cause of breeding failure (7.3%), followed by rat predation (6.3%). We also compared petrel and pigeon nest cavities and found considerable overlap in the physical size of nest sites. Our study provides insights into an overlooked impact of the invasive rock pigeon: nest competition with small seabirds. We encourage more research on the effects of pigeons on nest density, as well as disease and pathogen transmission, and vegetation changes within seabird colonies., Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This study was funded by the project INTERREG MAC/4.6d/157 LuMinAves

Grey-faced Petrels (Pterodroma gouldi) are a colonial burrowing seabird predominantly nesting on offshore islands of the upper North Island of New Zealand. We studied their annual breeding biology and the impact of Southern Oscillation Index climatic effects by measuring colony productivity and chick growth rates from 2011 to 2015 on Te Hāwere-a-Maki as unfavorable warmer La Niña conditions changed to favorable cooler El Niño conditions. Across all five years, annual chick hatching consistently occurred within a one-week period at the end of August but fledging variably occurred over a three-week period following Christmas. Because ship rats are pest controlled on Te Hāwere-a-Maki, we found only a slight reduction in breeding success with nearby predator-free islands. However, chick growth and fledging rates were significantly higher under El Niño conditions occurring towards the end of our study, rather than La Niña conditions at the start of our study. Our regular handling of chicks for monitoring had no discernible impact compared to a set of control chicks. The combined impacts of annual variation in predation and climate mean the Grey-faced Petrel colony on Te Hāwere-a-Maki maintains a constant population size of around 100 burrows.

Incidental mortality (bycatch) in fisheries represents a threat to marine vertebrates. Research has predominantly focussed on bycatch in longline fisheries, but bycatch from gillnet fisheries is of increasing concern. To address this concern, we combined comprehensive biologging data sets and multiple sources of fishing effort data to assess the spatial overlap of 3 diving seabird species during the breeding season (common guillemot Uria aalge, razorbill Alca torda and European shag Phalacrocorax aristotelis) with UK gillnet fisheries. Species distribution models based on birds’ diving behaviour identified areas of elevated bycatch risk where high levels of diving activity and fishing effort coincided. In addition, we identified times of day and water depths where diving activity, and hence bycatch risk, may be concentrated. Bycatch risk hotspots for all 3 species were identified along the north-east coast of England. Risk hotspots were also identified along the Pembrokeshire coast for both auk species and along the Cornish coast for shag. Lack of fishing effort data for smaller vessels made it difficult to assess seabird-fishery overlap in Scottish waters. Across species, diving activity was lower at night. For razorbill and guillemot, dive depth tended to increase at sunrise and decrease after sunset. For shag, dive depth showed no diel pattern but was associated with water depth. Our findings should assist in targeting spatio-temporal measures and designing deterrent devices to reduce bycatch. However, scarcity of data on the behaviour of gillnet fishers at comparable spatio-temporal resolution as seabird movement data remains a constraint to fully understanding seabird-fisheries interactions.

Seabirds are keystone species, providing inter-habitat connectivity by transporting vast quantities of nutrients from their pelagic feeding grounds to terrestrial and marine ecosystems, dictating community structure and dynamics, and providing multiple ecosystem services. This flow of nutrients is being disrupted by human activities, such as invasive species, and seabirds are now one of the most threatened bird groups. Whether seabird nutrients are cycling through nearshore, temperate systems, in particular in the United Kingdom (UK), impacting biodiversity and productivity, and how these inputs may vary temporally, remains unknown. The impact of nutrient subsidies to the Farne Islands, Northumberland, areas of high seabird densities during breeding season, was compared to nearby low seabird density areas on the Northumberland coast. Seabird densities and nitrogen inputs of up to 2334 and 1054 times higher, respectively, on seabird islands resulted in both substantially enriched nitrogen stable isotope (δ15N) values and higher total nitrogen content in terrestrial and intertidal organisms, including soil, terrestrial plants, lichen, barnacles, and limpets, and just higher δ15N values in macroalgae and turf algae. Temporal variation was also detected, though, surprisingly, nitrogen loads were higher during early breeding season. Some support was found for increased biodiversity in intertidal areas of seabird islands, in higher densities of intertidal predators and marginally greater algal species richness, though diversity differences were small overall. A marginal difference in limpet size was found, whilst on plots artificially cleared to simulate a disturbance event, barnacles were unexpectedly found to recolonise faster on mainland sites, which was likely caused by the mainland’s increased exposure level. These findings provide evidence that seabirds are cycling pelagic nutrients into terrestrial and intertidal ecosystems on UK islands, though support for seabird nutrient input increasing biodiversity and productivity was mixed. Given the threats to seabirds globally, these findings promote seabird conservation, including the removal of invasive species, such as rat eradication programmes.

Climatic factors drive changes in forage fish communities and may influence the productivity of piscivorous predators, but specific mechanisms of response remain poorly known. Between 1984 and 2020, we studied the rhinoceros auklet Cerorhinca monocerata, a seabird breeding in the western North Pacific at Teuri Island, Japan. We tested the hypothesis that climate-mediated prey-switching affects ‘food packaging’ (i.e. the way energy is brought to dependent offspring) and breeding success by quantifying relationships between climate, prey energy density, amount of food delivered, and the growth and survival of chicks. Prey composition switched 4 times: 1988-1992, 1997-1998, 2013-2014, and 2017-2018. All but the last of these switches were associated with (lagged) shifts in seawater temperature/Pacific Decadal Oscillation. Rhinoceros auklets brought multiple fish in each meal-load to chicks, and numbers were inversely correlated with the size of the fish. These relationships varied between fish species. The heaviest meal-loads were achieved when diets were dominated by anchovy Engraulis japonicas, which occurred during warm phases (1992-2013). Chick production, growth rates, and mass at fledgling were also highest during the warm phases. This study shows that climate affects seabird reproduction by shifting the manner in which food is selected relative to changes in forage fish community structure and abundance.

Morphological identification of digested prey remains from a generalist predator can be challenging, especially when attempting to match degraded remains to taxonomic keys. DNA techniques, whereby prey is sequenced and matched to large public nucleotide sequence databases, are increasingly being used to augment morphological identification. We used “metaBARFcoding” (DNA metabarcoding) to target a region of the cytochrome c oxidase subunit I (COI) mitochondrial gene to identify prey in highly digested regurgitations from Christmas shearwaters Puffinus nativitatis at Hōlanikū (Kure Atoll). Metabarcoding was used to bulk‐process 92 water samples from regurgitations collected from 2009 to 2017, providing an overview of the seabird's diet. We additionally Sanger‐sequenced 100 prey items from 50 randomly chosen regurgitations to verify that metabarcoding characterized key components of the diet. The metabarcoding technique identified 87 unique taxa from 29 families of fish and squid, spanning diverse taxa, including reef‐associated, pelagic–oceanic, and mesopelagic species. Rare prey (frequency of occurrence ≤5% of samples) constituted 66% of the species richness, demonstrating the highly diverse diet of this generalist predator. Overall, 81% of the families detected in the contemporary diet were previously documented in Christmas shearwater diets from the Northwestern Hawaiian Islands. Our results indicate that metabarcoding the COI region is useful in identifying a wide range of taxa from highly digested regurgitations, thus facilitating this approach to study seabird diets.

Investigating the foraging patterns of tropical seabirds can provide important information about their ocean habitat affinities as well as prey choice. Foraging studies of Red-billed Tropicbird Phaethon aethereus populations in the Caribbean are lacking. We sought to rectify this by opportunistically sampling regurgitates at nest sites on the island of St. Eustatius, Lesser Antilles, and by linking the GPS tracks of foraging adults to remotely sensed environmental variables. Diet samples were dominated by Exocoetidae (59.5%) and Belonidae (14.9%), although we were unable to identify 25.5% of samples due to digestion. Tropicbirds nesting on St. Eustatius exhibited diurnal foraging patterns, foraged in deeper waters with higher chlorophyll concentration, and consumed fewer Exocoetidae species compared to travelling behaviour. The maximum distance travelled from the colony was 953.7 km, with an average trip length of 176.8 (± 249.8) km. The biologged birds crossed multiple exclusive economic zones and marine protected areas, and on that basis, we suggest that efforts to protect and conserve this species may require transboundary collaboration throughout the wider Caribbean.

Although mechanisms of genetic and social inheritance have been implicated in determining the migratory routes of birds, it is unclear what their relative contributions are in species where outbound and return migration routes differ (‘loop migrants’). Here, we used biologging devices to follow Manx Shearwaters Puffinus puffinus, a long-lived seabird with a trans-Atlantic loop migration, from before their first migration until their 3rd calendar year. We found that Shearwaters undertake first migration without their parents, setting off almost immediately upon fledging and moving along a more direct trajectory than adults, before wintering in the same part of the South Atlantic as adult conspecifics and subsequently iteratively developing their return migration route over the next 3 years, each time returning – unlike adults – via a Western Atlantic route. We propose that the first outbound migration in Manx Shearwaters is broadly consistent with a genetically inherited vector, that both the outbound and the return migration trajectories are unlikely to be learnt from experienced conspecifics, and that return migration in Manx Shearwaters (and perhaps loop migrants more generally) may be informed by genetically inherited information and/or local environmental conditions.

Funder: Stichting Ave Fenix Europa, Funder: Arcadia Fund; Id: http://dx.doi.org/10.13039/100012088, Funder: MAVA Foundation; Id: http://dx.doi.org/10.13039/100013324, Funder: David and Claudia Harding Foundation, Funder: Research England, Species reliant on both the terrestrial and marine realms present a challenge for conventional species distribution models (SDMs). For such species, standard single���realm SDMs may omit key information that could result in decreased model accuracy and performance. Existing approaches to habitat suitability modeling typically do not effectively combine information from multiple realms; this methodological gap can ultimately hamper management efforts for groups such as seabirds, seals, and turtles. This study, for the first time, jointly incorporates both terrestrial information and marine information into a single species distribution model framework. We do this by sampling nearby marine conditions for a given terrestrial point and vice versa using parameters set by each species��� mean maximum foraging distance and then use standard SDM methods to generate habitat suitability predictions; therefore, our method does not rely on post hoc combination of several different models. Using three seabird species with very different ecologies, we investigate whether this new multi���realm approach can improve our ability to identify suitable habitats for these species. Results show that incorporating terrestrial information into marine SDMs, or vice versa, generally improves model performance, sometimes drastically. However, there is considerable variability between species in the level of improvement as well as in the particular method that produces the most improvement. Our approach provides a repeatable and transparent method to combine information from multiple ecological realms in a single SDM framework. Important advantages over existing solutions include the opportunity to, firstly, easily combine terrestrial and marine information for species that forage large distances inland or out to sea and, secondly, consider interactions between terrestrial and marine variables.

Little has been reported on moult in sulids, including gannets. The Cape Gannet Morus capensis is an endangered seabird endemic to southern Africa. We describe the timing, duration, symmetry and se...

Globally, human population growth, its associated pollution and the vast scale of industrialised fisheries are having negative impacts on oceanic food webs, affecting top predators such as seabirds. We used stable isotope (δ15N and δ13C) analyses of feathers to investigate the contemporary structure and long-term changes in a near-shore community of 5 seabird species in northern Aotearoa New Zealand. Feathers were collected from museum specimens or live individuals (collected between 1878 and 2019) in Tīkapa Moana, the Hauraki Gulf, a marine habitat increasingly threatened by overfishing and urbanisation. To tease out the effects of baseline ecosystem versus seabird distributional changes, we analysed muscle isotope values of forage fishes collected over 43 yr (1976-2019) and provide isotopic data from contemporary prey species sampled within the region. Contemporary δ15N and δ13C values were consistent with existing data on diet and foraging distribution of the 5 seabird species. Values of δ15N declined in only 1 of 5 species studied, suggesting little change in the trophic position of the other species over time. However, δ13C values declined in 3 species, and a lack of change in the δ15N and δ13C values of forage fish suggests that this change is reflective of a behavioural shift in the distribution of the birds. However, changes in isotopic baselines over the sampling period cannot be ruled out and require further investigation. Our results demonstrate the value of stable isotope analyses of contemporary and archived samples as a cost effective, non-invasive method for monitoring coastal seabirds in a changing world.

The Natural Park of the Coral Sea (“Park”) presents itself as “one of the largest marine protected areas in the world”; the activities undertaken in this Park are presented as “sustainable” and “responsible”: what are the facts? Here, we aim at identifying the recurring themes of the Park's communication and comparing the content of the Park's public communiqués with the knowledge available in the scientific literature. All the communiqués accessible on the Park’s Internet site (N = 160, produced from October 2013 to March 2023) were compiled and analyzed in order to identify the type of information displayed. The most frequent words and word associations were identified and used to guide the analysis. A particular lexicon was thus compiled, where the words "management", "monitoring", "development", "biodiversity", "preservation", "sustainability", "conservation" and "innovation" dominated. We identified as the main themes of the Park's communication: inventories and "monitoring", scientific research, tourism, fishing, so-called "emblematic" species and expertise. The production of images and image exhibitions and festivals were also frequently mentioned, as well as the highlights of governance and management. An unacknowledged goal of the Park's communication was to present as acceptable several economic activities that actually are incompatible with the preservation of species and ecosystems.; Le Parc naturel de la mer de Corail (« Parc ») se présente comme « une des plus grandes aires marines protégées mondiales » ; les activités qui y sont menées seraient « durables » et « responsables » : qu’en est-il réellement ? Ici, nous tentons de dégager les thèmes récurrents de la communication du Parc et de confronter le contenu des communiqués du Parc aux connaissances disponibles dans la littérature scientifique. L’ensemble des communiqués accessibles sur le site du Parc (N = 160, produits d’oct. 2013 à mars 2023) ont été compilés et analysés afin de cerner le type d’information affichée. Les mots et associations de mots les plus fréquents ont été relevés et utilisés pour orienter l’analyse. Un lexique particulier a pu ainsi être constitué, où dominent les mots « gestion », « suivi », « développement », « biodiversité », « préservation », « durabilité », « conservation » et « innovation ». Nous avons identifié comme thèmes principaux de la communication du Parc : les inventaires et « suivis », la recherche scientifique, le tourisme, la pêche, les espèces dites « emblématiques » et l’expertise. La production d’images et les expositions et festivals de l’image sont aussi fréquemment évoqués, ainsi que les temps forts de la gouvernance et de la gestion. Un but inavoué de la communication du Parc est de présenter comme acceptables plusieurs activités économiques en réalité peu compatibles avec la préservation des espèces et des écosystèmes.

Long-distance migratory seabirds need to adjust their migration strategy according to internal (breeding, molting) and external factors (seasonality, resource availability). Time-minimizing strategies are common during spring migration to arrive at the optimal time to breed. We studied the annual movements and migration strategy of the long-tailed jaeger Stercorarius longicaudus, a small arctic-nesting seabird. First, we documented year-round movements (routes, wintering sites) of male and female jaegers breeding in the Canadian Arctic. We then compared their migration strategies between seasons (phenology, stopover use, travel distance, speed) to determine whether they adopt a time-minimizing strategy in spring. Over 6 yr, we collected 43 tracks from geolocators deployed on Bylot and Igloolik Islands. Jaegers departed the breeding site over a 5 wk period and traveled on average 32375 km (round trip) before returning to breed, one of the longest documented migrations on Earth. Birds used a major stopover area east of the Grand Banks of Newfoundland in spring and fall, and wintered in high marine productivity areas of the South Atlantic. Unexpectedly, the spring migration was 40% longer and 32% slower than in fall, and birds increased their time spent on water (foraging and/or resting) by 61%. A time-minimizing strategy in fall may help to reach the wintering site rapidly and start molting early. In spring, a fly-and-forage strategy seems to be adopted to increase foraging effort, probably for the accumulation of body reserves before breeding and in anticipation of unfavorable conditions that may prevail at arrival on their arctic breeding site.

Innovation, a process that plays an important role in the ecology and evolution of species, is considered an expression of behavioral flexibility in animals. Here we analyzed innovative problem-solving ability and performance enhancement through learning in the Olrog's Gull (Larus atlanticus), under controlled processes and experimental conditions. Trials were undertaken with nine adult individuals captured at a highly urbanized coastal area of Argentina. Each individual was presented with a Plexiglas box that could be opened by pushing or pulling two lids, each lid leading to a separated food reward. We measured problem-solving ability through consumption latency and the number of solved lids. As explanatory variables, we measured contact rate, as a measure of persistence, and the number of effective contacts. The results showed that the contact rate and effective contacts did not affect variables related to problem-solving ability during the first confrontation of the individuals with the closed box. Consumption latency decreased significantly throughout the trials, and with increasing contact rate and effective contacts. The number of solved lids increased through the trials independently of the contact rate and the total effective contacts with the box. Although persistence did not influence individuals' performance during the problem-solving test; this variable affected individuals' ability to solve the task throughout trials. Learning was evidenced by the decrease in the resolution time across experiments, suggesting that successful individuals improved their performance probably through a trial-and-error process. Evaluation of behavioral responses of a threatened seabird to a novel problem-solving task adds knowledge to previous field studies and provides a better understanding of the ability of individuals to adjust their foraging behavior in highly urbanized areas used during the non-breeding season.

This research focuses on the historical demise of Hawaiian avifauna due to hunting by ancient Polynesians. Numerous documents, published since the early 1800s, were scrutinized and evaluated, these provided information on bird hunting and traditional Hawaiian practices. Hawaiians used birds as sources of feathers and food. Feathers were important symbols of power for Polynesians, in Hawai’i, feathers were more highly prized than other types of property. Feathers used for crafts were obtained from at least 24 bird species, however, the golden feathers of ‘ō‘ō and mamo birds made them primary targets for birdhunters, both birds became extinct by the late 1800s. Feathers were utilized for many items, including ‘ahu‘ula [cloaks], mahiole [war helmets], and kāhili [standards]. Most garments utilized a considerable number of feathers, a cloak for Kamehameha consumed the golden feathers of 80,000 mamo birds. Bird meat was an important food item for native Hawaiians. It is believed that most birds were killed after being plucked, historical sources mention ~30 bird species were consumed. The ‘ua‘u (Pterodroma sandwichensis), a currently endangered seabird, was ruthlessly hunted and avidly eaten. Its current geographical range is just a minute fraction of its former one, now, ‘ua‘us are largely restricted to inaccessible cliffs at Haleakalā Crater (Maui).

Site fidelity is driven by predictable resource distributions in time and space. However, intrinsic factors related to an individual’s physiology and life-history traits can contribute to consistent foraging behaviour and movement patterns. Using 11 yr of continuous geolocation tracking data (fall 2008 to spring 2019), we investigated spatiotemporal consistency in non-breeding movements in a pelagic seabird population of black-legged kittiwakes Rissa tridactyla breeding in the High Arctic (Svalbard). Our objective was to assess the relative importance of spatial versus temporal repeatability behind inter-annual movement consistency during winter. Most kittiwakes used pelagic regions of the western North Atlantic. Winter site fidelity was high both within and across individuals and at meso (100-1000 km) and macro scales (>1000 km). Spatial consistency in non-breeding movement was higher within than among individuals, suggesting that site fidelity might emerge from individuals’ memory to return to locations with predictable resource availability. Consistency was also stronger in space than in time, suggesting that it was driven by consistent resource pulses that may vary in time more so than in space. Nonetheless, some individuals displayed more flexibility by adopting a strategy of itinerancy during winter, and the causes of this flexibility are unclear. Specialization for key wintering areas can indicate vulnerability to environmental perturbations, with winter survival and carry-over effects arising from winter conditions as potential drivers of population dynamics. : Spatial distribution · Individual consistency · Migration · Repeatability · Nearest neighbor distance · Biologging · Global Location Sensors · GLS

Sharing the same wintering grounds by avian populations breeding in various areas may synchronize fluctuations in vital rates, which could increase the risk of extinction. Here, by combining multi-colony tracking with long-term capture-recapture data, we studied the winter distribution and annual survival of the most numerous Arctic seabird, the little aukAlle alle. We assessed whether little auks from different breeding populations in Svalbard and Franz Josef Land use the same wintering grounds and if this leads to synchronized survival. Our results indicate that birds from the Svalbard colonies shared similar wintering grounds, although differences existed in the proportion of birds from each colony using the different areas. Little auks from Franz Josef Land generally spent the winter in a separate area, but some individuals wintered in the Iceland Sea with Svalbard populations. Survival data from 3 Svalbard colonies collected in 2005-2018 indicated that sharing wintering grounds did not synchronize little auk annual survival rates. However, it is clear that the Iceland Sea is an important wintering area for little auks, and environmental changes in this area could have widespread impacts on many populations.

Despite the global scale of gillnet bycatch, universal measures that effectively reduce bycatch of seabirds in gillnets have not been found. Bycatch in coastal gillnet fisheries is an ongoing threat for several seabird species. Strategies to reduce seabird bycatch in gillnet fisheries were evaluated, focusing on the effectiveness of time-area fishing restrictions and gear-switching to meet seabird conservation objectives, ensure fisher acceptance, and avoid unintended consequences. A review of case studies showed that variations in the spatial and temporal distributions of target and non-target species may cause a mismatch between time-area regulations and high bycatch, but consideration of bycatch species behavior can help define effective fine-scale spatial and temporal measures. The potential for meeting conservation objectives through gear-switching is promising, with some further development needed for successful application. Combining measures (e.g., time-area fishing restrictions, gear-switching, visual and acoustic deterrents) may be feasible in some regions, if fine-scale spatial and temporal information about the overlap of seabirds and gillnet gear is available. A holistic approach to reduce seabird bycatch in gillnets, including understanding of seabird biology, habitat preference, and feeding ecology combined with information about fishing activity, target species, and socioeconomic impacts provides a framework to develop mitigation measures.

Variació temporal de la diversitat, abundància i ús de l’hàbitat dels ocells marins a Punta La Metalera (Arequipa, al sud del Perú) Els sistemes d’illes, illots i puntes guaneres proporcionen una extraordinària i àmplia varietat d’hàbitats, única per als ocells marins. Aquesta variabilitat determina l’estructura i la dinàmica de la comunitat. Hi ha pocs estudis sobre variació de la diversitat en el temps o sobre ús de l’hàbitat per part dels ocells en aquests sistemes del sud del Perú. Amb aquest objectiu vam analitzar aquests paràmetres a la Punta La Metalera (El Faro) des d’octubre de 2019 a març de 2020 en un cap d’Islay, Arequipa, al sud del Perú. En total vam registrar un total de 12 espècies, entre les quals una d’endèmica de la costa peruana (Cinclodes taczanowskii), una amb estatus d’amenaçada, Spheniscus humboldti, i quatre amb estatus de gairebé amenaçades (Phalacrocorax gaimardi, Pelecanus thagus, Sula variegata i Larosterna inca) algunes de les quals pertanyents al grup d’ocells guaners. Pel que fa a l’abundància, la família Laridae va ser la més abundant, amb una presència destacada de Larosterna inca amb el nombre més gran d’individus; la fluctuació temporal evidencia una abundància més gran d’espècies durant els mesos de desembre i gener. Els principals usos de l’hàbitat van ser el descans, l’arranjament de les plomes amb el bec i l’alimentació. Tanmateix, els registres de nidificació de sis espècies també suggereixen aquest ús. Aquesta àrea té una importància significativa per al desenvolupament de les espècies aquí registrades atesa l’escassa informació disponible sobre la costa sud, la grandària poblacional i la reproducció d’algunes de les espècies registrades.

Rodent predators are implicated in declines of seabird populations, and removing introduced rats, often, but not always, results in the expected conservation gains. Here we investigated the relationship between small mammal (Norway rat, wood mouse and pygmy shrew) abundance and Manx shearwater breeding success on the island of Rum, Scotland, and tested whether localised rodenticide treatments (to control introduced Norway rats) increased Manx shearwater breeding success. We found that Manx shearwater breeding success was negatively correlated with late summer indices of abundance for rats and mice, but not shrews. On its own, rat activity was a poor predictor of Manx shearwater breeding success. Rat activity increased during the shearwater breeding season in untreated areas but was supressed in areas treated with rodenticides. Levels of mouse (and shrew) activity increased in areas treated with rodenticides (likely in response to lower levels of rat activity) and Manx shearwater breeding success was unchanged in treated areas (p

Many species of gulls have expanded their range worldwide and massively occupied coastal islands. These colonisations have not only affected the biotic interactions among seabird colonies, but also altered the soil chemistry through excrement accumulation. To test whether the seabird colony size determines nutrient levels of island soil, we carried out a field study during a breeding season on six Mediterranean islands in central North Algeria which harbour different population sizes of the yellow-legged gull (Larus michahellis). We sampled the soil and measured a suite of physical (area, floral richness, clay, fine silt, large silt, fine sand and large sand content) and chemical (pH, electric conductivity, limestone, organic matter, N, P, Ca, Mg, K and Na) properties and the colony size and density of the yellow-legged gull. Using principal component analysis, we found that the six islands showed some physicochemical similarities, but island area, colony size and soil N and P levels structured the islands into different groups. Although there was evidence of a positive relationship between colony size and N and P soil levels, this relationship was not linear. Our results suggest that historical rather than punctual data on the colony size of seabirds might give more robust predictions of soil physicochemistry of islands.

The Pterodroma feae complex comprises three cryptically looking gadfly petrels (Cape Verde Pterodroma feae, Desertas Pterodroma deserta, and Zino’s Pterodroma madeira), once regarded as a single species, the Fea’s Petrel, P. feae. Recent research using geolocators to track and understand their movements away from breeding grounds demonstrated that both Zino’s and Desertas Petrels do undergo some long-distance movements. They perform a trans-equatorial migration to remote, previously unknown, wintering grounds, in Brazilian waters off the northeast and southern coast of Brazil during their non-breeding season. However, despite several decades of systematic and intensive beached seabird projects along extensive stretches of the Brazilian coast in these two regions, no specimens of either of these gadfly petrels have been reported. Here, we document two photographic specimen records of gadfly petrels off the Brazilian coast, provide comparative criteria for at sea identification and discuss difficulties to determine species level. First, a heavy-billed male Desertas Petrel was photographed over the continental shelf off the Rio Grande do Sul, southern Brazil, and a second specimen off Espirito Santo, southeastern Brazil, over the Vitoria Seamount, either a Desertas or a Cape Verde Petrel. Apart from Brazilian records based solely on geolocator tracking results, these seem to be the first documented specimen records for Brazil of any species within the feae-group, as well as for the southwestern Atlantic Ocean. Further, these records confirm that Brazilian offshore waters are important non-breeding feeding grounds for the feae-group.

Fisheries bycatch mortality poses a primary threat to the majority of the world’s 22 albatross species, 15 of which are at risk of extinction. Although quantitative estimates of albatross bycatch are often unavailable due to a relative or total absence of monitoring, spatial overlap between fisheries and albatrosses is often used to estimate the extent of interaction, a proxy for exposure to bycatch, and to inform avoidance and mitigation actions. Using comprehensive records of commercial demersal longline and trap fishing and survey information for albatrosses (black-footed albatross Phoebastria nigripes, Laysan albatross P. immutabilis, short-tailed albatross P. albatrus), the extent of spatial potential interaction was estimated in Canada’s Pacific coast waters and examined across breeding and non-breeding seasons. The distributions of albatrosses and longline and trap fisheries were found to substantially overlap, with potential interaction hotspots concentrated along the continental shelf break. Trap fisheries reported 1 albatross bycatch incident, suggesting that these fisheries are responsible for negligible albatross mortalities. In contrast, >80% of recorded albatross bycatch incidents occurred within 10 km of albatross-longline fisheries hotspot locations, providing evidence that longline-albatross potential interaction hotspots represent actual areas of elevated bycatch mortality risk. Indicative of potential conservation concern, 60% of short-tailed albatross sightings occurred within 10 km, and 93% within 30 km, of longline-albatross potential interaction hotspots. By contributing knowledge regarding albatross-fisheries interactions, in addition to undertaking the first evaluation of albatross-fisheries hotspots with recorded bycatch incidents on Canada’s Pacific coast, this study represents a step towards enhancing albatross conservation through bycatch avoidance and mitigation.

Extreme weather events are increasing in frequency, causing disruption to global ecosystems. Large-scale events, such as marine heatwaves, can impact the abundance of prey species, which consequently influences the behaviour of top-level predators such as seabirds. The short-tailed shearwater Ardenna tenuirostris is a trans-hemispheric migrant with typically a highly synchronous breeding phenology. Here, we document short-tailed shearwater colony occupancy for the period 2011-2020, with a focussed assessment of their breeding success in the 2019/20 season, which followed a marine heatwave that occurred predominantly in the non-breeding areas in the North Pacific Ocean. The return of the birds to their breeding colonies in southeast Australia was delayed by approximately 2 wk in October 2019, and the subsequent breeding season ended with only 34% breeding success, with nest abandonment beginning in the incubation phase. A North Pacific marine heatwave in 2019, associated with a mass mortality event of over 9000 birds (‘wreck’ of beach-washed birds), led to reduced adult body condition and carry-over effects causing egg and chick failures during the subsequent breeding season. Localised weather events (i.e. flooding of burrows due to heavy rainfall) also influenced breeding outcomes of the 2019/20 season. The relationship between wreck events and seabird breeding ecology is an understudied area, partly due to the difficulties around quantifying the scale of wrecks. Our study is one of few that documents poor seabird breeding success following the extreme marine conditions which have persisted in the North Pacific Ocean since 2013.

Feathers play an important role in many aspects of avian ecology, including sexual selection, thermoregulation and flight. However, several external stressors can negatively impact plumage conditio...

Oil spills are rare in Antarctica. They threaten flying birds and penguins. This is the first report on the interactions of seabirds with oil in the area of the Mirny Station (East Antarctica). The purpose of the study is to determine the total number of seabird species interacting with oil in and around the Mirny Station, to assess the extent of pollution and to identify the most important sites of interactions. Oil pollution is found on the ground, on the continental ice and, on the seawater surface, both directly in the Mirny and beyond. Five species of seabirds were in contact with oil. Oil pollution threats have been identified for breeding and molting Adélie Penguins (Pygoscelis adeliae) and vagrant Macaroni Penguins (Eudyptes chrysolophus). Less affected by oil pollution during the breeding season were tube-nosed bird species and skuas. The most important places of interaction of seabirds with oil are at Cape Mabus, on the islands of Zykov, Tokarev, and Stroiteley. Evidence of long-term oil pollution of the environment is indicative of the chronic nature of the impacts on the coastal ecosystem.

BackgroundStudies on animal behaviour often involve the quantification of the occurrence and duration of various activities. When direct observations are challenging (e.g., at night, in a burrow, at sea), animal-borne devices can be used to remotely record the movement and behaviour of an animal (e.g., changing body posture and movement, geographical position) and/or its immediate surrounding environment (e.g., wet or dry, pressure, temperature, light). Changes in these recorded variables are related to different activities undertaken by the animal. Here we explored the use of animal-borne acoustic recorders to automatically infer activities in seabirds.ResultsWe deployed acoustic recorders on Cape gannets and analysed sound data from 10 foraging trips. The different activities (flying, floating on water and diving) were associated with clearly distinguishable acoustic features. We developed a method to automatically identify the activities of equipped individuals, exclusively from animal-borne acoustic data. A random subset of four foraging trips was manually labelled and used to train a classification algorithm (k-nearest neighbour model). The algorithm correctly classified activities with a global accuracy of 98.46%. The model was then used to automatically assess the activity budgets on the remaining non-labelled data, as an illustrative example. In addition, we conducted a systematic review of studies that have previously used data from animal-borne devices to automatically classify animal behaviour (n = 61 classifications from 54 articles). The majority of studies (82%) used accelerometers (alone or in combination with other sensors, such as gyroscopes or magnetometers) for classifying activities, and to a lesser extent GPS, acoustic recorders or pressure sensors, all potentially providing a good accuracy of classification (> 90%).ConclusionThis article demonstrates that acoustic data alone can be used to reconstruct activity budgets with very good accuracy. In addition to the animal’s activity, acoustic devices record the environment of equipped animals (biophony, geophony, anthropophony) that can be essential to contextualise the behaviour of animals. They hence provide a valuable alternative to the set of tools available to assess animals’ behaviours and activities in the wild.

The analysis of feeding strategies in animals is one of the most important topics in foraging ecology. The individual’s foraging behavior depends on both the individual’s own actions and the behavior of other foragers. Here we analyse the effect of the sex and group size on the foraging behavior of immature Olrog’s Gull (Larus atlanticus Olrog, 1958), endemic to the Atlantic coast of southern South America and regionally listed a threatened species. Birds were captured, banded, sexed, and aged during the non-breeding season in Mar Chiquita coastal lagoon, Argentina. The foraging behavior was quantified by observations made on individuals of known identity, recording the size of foraging groups, as well as prey size and type. Foraging parameters estimated were foraging effort, capture rate, and foraging efficiency. Males spent more time in agonistic behavior and captured larger prey. With an increase in group size, the capture rate, the capture of small crabs by males, and the foraging effort were higher. The agonistic behaviors, size of consumed prey, and foraging effort were affected by individual identity. Our study pinpoints factors underlying variation in the foraging behavior of Olrog’s Gulls and illustrates the importance of modelling individual variation when analyzing foraging behavior.

International audience; Mercury (Hg) is a toxic trace element widely distributed in the environment, which particularly accumulates in top predators, including seabirds. Among seabirds, large gulls (Larus sp) are generalist feeders, foraging in both terrestrial and marine habitats, making them relevant bioindicators of local coastal Hg contamination. In the present study, we reported blood Hg concentrations in adults and chicks of four different gull species breeding on the French Atlantic coast: the European herring gull (Larus argentatus), the Lesser black-backed gull (L. fuscus), the Great black-backed gull (L. marinus) and the Yellow-legged gull (L. michahellis). We also investigated the potential role of foraging ecology in shaping Hg contamination across species, using the unique combination of three dietary tracers (carbon, nitrogen and sulfur stable isotopes) and biologging (GPS tracking). A high concentration of Hg was associated with high trophic position and a marine diet in gulls, which was corroborated by birds’ space use strategy during foraging trips. Adults of all four species reached Hg concentrations above reported toxicity thresholds. Specifically, adults of Great black-backed gulls had a high trophic marine specialized diet and significantly higher Hg concentrations than the three other species. Blood Hg was 4–7 times higher in adults than in chicks, although chicks of all species received mainly marine and high trophic position prey, which is expected to be the cause of blood Hg concentrations of toxic concern. By using both stable isotopes and GPS tracking, the present study provides compelling insights on the main feeding habits driving Hg contamination in a seabird assemblage feeding in complex coastal environments.

This project contains the data, model outputs and R scripts to reproduce the results presented in our paper "Spying on your neighbours? Social information affects timing of breeding and stress hormone levels in a colonial seabird".

Migratory species have geographically separate distributions during their annual cycle, and these areas can vary between populations and individuals. This can lead to differential stress levels being experienced across a species range. Gathering informa-tion on the areas used during the annual cycle of red- throated divers (RTDs; Gavia stel-lata) has become an increasingly pressing issue, as they are a species of concern when considering the effects of disturbance from offshore wind farms and the associated ship traffic. Here, we use light- based geolocator tags, deployed during the summer breeding season, to determine the non- breeding winter location of RTDs from breed-ing locations in Scotland, Finland, and Iceland. We also use δ15N and δ13C isotope signatures, from feather samples, to link population- level differences in areas used in the molt period to population- level differences in isotope signatures. We found from geolocator data that RTDs from the three different breeding locations did not overlap in their winter distributions. Differences in isotope signatures suggested this spatial separation was also evident in the molting period, when geolocation data were unavailable. We also found that of the three populations, RTDs breeding in Iceland moved the shortest distance from their breeding grounds to their wintering grounds.In contrast, RTDs breeding in Finland moved the furthest, with a westward migration from the Baltic into the southern North Sea. Overall, these results suggest that RTDs breeding in Finland are likely to encounter anthropogenic activity during the win-ter period, where they currently overlap with areas of future planned developments. Icelandic and Scottish birds are less likely to be affected, due to less ship activity and few or no offshore wind farms in their wintering distributions. We also demonstrate that separating the three populations isotopically is possible and suggest further work to allocate breeding individuals to wintering areas based solely on feather samples. Migratory species have geographically separate distributions during their annual cycle, and these areas can vary between populations and individuals. This can lead to differential stress levels being experienced across a species range. Gathering information on the areas used during the annual cycle of red-throated divers (RTDs; Gavia stellata) has become an increasingly pressing issue, as they are a species of concern when considering the effects of disturbance from offshore wind farms and the associated ship traffic. Here, we use light-based geolocator tags, deployed during the summer breeding season, to determine the non-breeding winter location of RTDs from breeding locations in Scotland, Finland, and Iceland. We also use delta N-15 and delta C-13 isotope signatures, from feather samples, to link population-level differences in areas used in the molt period to population-level differences in isotope signatures. We found from geolocator data that RTDs from the three different breeding locations did not overlap in their winter distributions. Differences in isotope signatures suggested this spatial separation was also evident in the molting period, when geolocation data were unavailable. We also found that of the three populations, RTDs breeding in Iceland moved the shortest distance from their breeding grounds to their wintering grounds. In contrast, RTDs breeding in Finland moved the furthest, with a westward migration from the Baltic into the southern North Sea. Overall, these results suggest that RTDs breeding in Finland are likely to encounter anthropogenic activity during the winter period, where they currently overlap with areas of future planned developments. Icelandic and Scottish birds are less likely to be affected, due to less ship activity and few or no offshore wind farms in their wintering distributions. We also demonstrate that separating the three populations isotopically is possible and suggest further work to allocate breeding individuals to wintering areas based solely on feather samples.

The Antarctic and the surrounding Southern Ocean are currently subject to rapid environmental changes and increasing anthropogenic impacts. Seabird populations often reflect those changes and so act as indicators of environmental variability. Their population trends may provide information on a variety of environmental parameters on the scale of years or decades. We therefore provide long-term data on the cape petrel (Daption capense) population from a long-term monitoring program on Fildes Peninsula, South Shetland Islands, Maritime Antarctic, an area of considerable human activity. Our data, covering a period of 36 years, indicate some variability, but no clear trend in the number of breeding pairs between the breeding seasons 1985 and 2006. However, beginning in the 2008 season, the population decreased significantly and reached a minimum in the 2020 season. The mean annual decrease between 2008 and 2020 was 10.6%. We discuss possible causes of this strong negative population trend. Anthropogenic disturbance only affects a few breeding sites in the area and is therefore unable, on its own, to explain the consistent population decline at all the breeding sites studied. We think it more likely that reduced food availability was the main cause of the drastic decline in the cape petrel population.

Sexual competition is increasingly recognized as an important selective pressure driving species distributions. However, few studies have investigated the relative importance of interpopulation versus intrapopulation competition in relation to habitat availability and selection. To explain spatial segregation between sexes that often occurs in non-territorial and central place foragers, such as seabirds, two hypotheses are commonly used. The ‘competitive exclusion’ hypothesis states that dominant individuals should exclude subordinate individuals through direct competition, whereas the ‘niche divergence’ hypothesis states that segregation occurs due to past competition and habitat specialization. We tested these hypotheses in two populations of an extreme wide-ranging and sexually dimorphic seabird, investigating the relative role of intrapopulation and interpopulation competition in influencing sex-specific distribution and habitat preferences. Using GPS loggers, we tracked 192 wandering albatrosses Diomedea exulans during four consecutive years (2016–2019), from two neighbouring populations in the Southern Ocean (Prince Edward and Crozet archipelagos). We simulated pseudo-tracks to create a null spatial distribution and used Kernel Density Estimates (KDE) and Resource Selection Functions (RSF) to distinguish the relative importance of within- versus between-population competition. Kernel Density Estimates showed that only intrapopulation sexual segregation was significant for each monitoring year, and that tracks between the two colonies resulted in greater overlap than expected from the null distribution, especially for the females. RSF confirmed these results and highlighted key at-sea foraging areas, even if the estimated of at-sea densities were extremely low. These differences in selected areas between sites and sexes were, however, associated with high interannual variability in habitat preferences, with no clear specific preferences per site and sex. Our results suggest that even with low at-sea population densities, historic intrapopulation competition in wide-ranging seabirds may have led to sexual dimorphism and niche specialization, favouring the ‘niche divergence’ hypothesis. In this study, we provide a protocol to study competition within as well as between populations of central place foragers. This is relevant for understanding their distribution patterns and population regulation, which could potentially improve management of threatened populations.

In long-lived marine top-predators with delayed sexual maturity such as seabirds, adult survival is predicted to drive population dynamics. Major knowledge gaps exist for the cryptic sub-adult stages of the population. Yet as the oceans undergo dramatic change, investigating the trends of top-predator populations and their responses to environmental variability is key for a process-based understanding of climate change. Using integrated population models based on a longitudinal data set spanning nearly 2 decades, we investigated the demographic rates and environmental drivers shaping the dynamics of a longevous marine top-predator population, the black-browed albatross Thalassarche melanophris in the Falklands. We quantified the dynamics of the whole population, including its cryptic sub-adult stages, and examined the effects of candidate environmental covariates on adult survival and productivity parameters. We found that high survival rates of both adults and juveniles are the main contributors to the growth of this albatross population, the only one that is increasing in the South Atlantic. The breeding parameters were affected by environmental fluctuations through bottom-up processes, with a negative effect of higher sea surface temperatures and a positive effect of wind intensity. The relatively constant adult survival was influenced by deeper ecosystem changes, captured by large-scale indices (Southern Annular Mode). Approximately half of the total population is composed of sub-adults, and the population dynamics are highly sensitive to changes in juvenile survival; addressing current knowledge gaps in these cryptic life-history stages is therefore a conservation goal of primary importance.

Ocean mesoscale and submesoscale features, such as eddies and filaments, play a key role in the foraging ecology of marine predators, by concentrating nutrients and acting as aggregative structures for pelagic organisms. Highly pelagic seabirds may exploit these features to find profitable food patches in a dynamic and complex 3-dimensional spatial environment. Using miniaturized GPS loggers, we investigated whether foraging habitat selection of the Mediterranean storm petrel Hydrobates pelagicus melitensis, one of the smallest (ca. 28 g) seabirds worldwide, was affected by different static and dynamic oceanographic features during the breeding period. Individuals performed long foraging trips (up to 1113 km) in a relatively short time (1 to 2 d), covering large home ranges (up to 34370 km2), particularly during incubation. Different oceanographic features affected the at-sea distribution of storm petrels at different spatio-temporal scales. During incubation, individuals selected areas characterized by shallow waters and strong currents, conditions that may enhance vertical water mixing and increase food availability. During chick-rearing, they foraged closer to the colony, selecting shallow and productive areas, where increasing Lagrangian coherent structures and eddy kinetic energy enhanced foraging probability. These features could play an important role in storm petrels’ foraging habitat selection, especially during chick-rearing, given their need to find predictable food patches in a short timespan. Overall, our results suggest that marine circulation processes are key drivers of the at-sea distribution of this small pelagic surface predator.

形態: カラー図版あり, Physical characteristics: Original contains color illustrations, Accepted: 2021-03-10, 資料番号: PA2120030000

There is an absence of quantitative criteria and definitions for unusual or anomalous mortality events involving birds, often referred to as “wrecks”. These events most commonly involve seabirds, although terrestrial bird wrecks have also been documented. Typically, the peer-reviewed literature investigating wreck events lacks the details necessary to further our understanding of the circumstances and potential causes of these events. This study reviewed the peer-reviewed literature for wrecks involving Ardenna seabirds (shearwaters), and included grey literature and data collected by citizen science (community) groups. Our results showed a significant time-lag between wreck events and when the data was published in the peer-reviewed literature, which did not occur in the grey literature. Both the grey and peer-reviewed literature were often skewed towards reporting larger wreck events, with only the citizen science dataset capturing smaller wrecks. We outline a proposed framework for reporting mortality events, including the use of quantitative categories to document the numbers of birds involved and taxon-specific thresholds. In doing so, we aim to establish a framework to aid in the quantitative reporting and analyses of future seabird wrecks.

The seabird tick, Ixodes uriae, is a significant ectoparasite of penguins in Antarctica and of other seabirds, mainly in coastal, polar regions of the Northern and Southern hemispheres, but the tick’s distribution extends into more temperate regions as well. The expansive range of this tick suggests that it is exposed to a wide range of abiotic stresses, including dehydration, heat, and cold. To better understand how I. uriae responds to stress exposure, we examined cross-tolerance between dehydration and thermal stress based on survival analyses and used RNA-seq to monitor transcriptional responses to cold, heat, and dehydration. Slight dehydration improved cold, but not heat tolerance, whereas severe dehydration reduced subsequent thermal tolerance. Dehydration exposure prompted transcript-level shifts underlying protein metabolism, recovery from stress, and processes allowing subsequent rehydration by water vapor uptake. Both cold and heat stress yielded expression changes involved in cuticle modification. One gene increased in expression (enzyme P450) and one decreased (transcription factor Hairy) in response to all three stresses. This study provides the groundwork for assessing stress tolerance in this bipolar ectoparasite.

The tufted puffin Fratercula cirrhata (Charadriiformes: Alcidae) is distributed throughout the boreal and low Arctic areas of the North Pacific, from California, USA to Hokkaido, Japan. Few studies have investigated the genetic diversity of this species. Therefore, we analyzed the genetic diversity of two captive populations using nucleotide sequences of two mitochondrial loci (COX1 and D-loop) and one nuclear locus (RHBG). We sequenced these loci for birds from Tokyo Sea Life Park (Kasai Rinkai Suizokuen), originally from Alaska, and birds from Aqua World Oarai, originally from far eastern Russia. We found five COX1 haplotypes and 17 D-loop haplotypes for the mitochondrial loci, and obtained 14 predicted haplotypes for the nuclear RHBG locus. The major haplotypes of all three loci occurred in individuals from both populations. Thus, there were no clear genetic differences between the populations with respect to these three loci. Although the breeding range of the tufted puffin covers the boreal and low Arctic from California to Hokkaido, our results suggest that the species has not genetically diverged within its breeding range.

Parent–offspring recognition (POR) is fundamental in colonial birds when the potential intermingling of chicks is higher due to the large number and proximity of nests. In species with isolated nests, where chick presence in the nest is strong contextual evidence of kinship, there might be circumstances when the parent might doubt the identity of the chick, but not enough to reject it. Olfactory-based recognition of conspecifics and nest sites in birds has gained strong evidence suggesting a potential role of olfaction in POR. Despite that, there are no studies testing it. We used Scopoli's shearwater (Calonectris diomedea) as model colonial single-brooded species with a developed olfactory sense, usually breeding in well-spaced nests with low probability of chicks mixing. We tested the parent's ability to selectively respond to their own chick as opposed to a simpler rule of feeding any chick found in the nest by means of chick-fostering experiments. We designed two cross-fostering experiments using chicks of different ages to test whether the ability of parents to recognize a related chick develops over time, possibly after acquiring an own distinctive odour. Finally, we also manipulated nests’ odour to disentangle the confounding effect of nest site recognition from POR when parents return at night. All experimental chicks were adopted by parents as the weight and bill growth of cross-fostered chicks did not differ significantly from the control group. We recorded a small difference in weight when foster chicks were inside an odour-manipulated nest; although we did not record weight loss in experimental chicks, only a steeper increase in weight was observed in control chicks. In conclusion, adoption in Scopoli's shearwater seems to follow the rule "if the young is in my nest, accept it" proposed by Beecher (1991) for species with spatially separated nests and low chick mobility. Fundação para a Ciência e Tecnologia - FCT info:eu-repo/semantics/acceptedVersion

Albatross bycatch has been increasing over the past decade in the US tuna longline fishery of the central North Pacific. A controlled field experiment was used to assess the efficacy of bird scaring or tori lines as a seabird bycatch mitigation measure for this fishery in a 3-factor sampling design with other mitigation methods (blue-dyed bait, offal discharge). A multilevel geoadditive Bayesian regression modeling approach was used to assess 3 albatross-gear interaction metrics (attempted contacts, contacts, captures) recorded for each longline set using an electronic monitoring system. We found albatross contacts with baited hooks were ca. 3 times (95% highest posterior density interval [HDI] 1–7) less likely for sets equipped with tori lines rather than without tori lines. Attempts to contact baited hooks were ca. 2 times (95% HDI 1–4) less likely for tori line-equipped sets. Albatrosses were also less likely to be captured in tori line sets but captures were too few to support strong inference compared with the contact rates. Tori lines were therefore found to be an effective management measure to mitigate albatross interactions in this fishery. Offal discharge during setting, however, was associated with higher seabird interactions—but that inference was not strong since offal discharge and blue-dyed bait were confounded treatments in some sets. Nonetheless, it was apparent that neither offal discharge nor blue-dyed bait was helpful in reducing albatross interactions in this trial and so the efficacy of those measures warrants further experimental investigation.

The stability of individual acoustic features is fundamental in social species, and more importantly in monogamous and territorial species, showing long-term fidelity both to the partner and the breeding site. In this study, the stability over time of two discrete vocal types was investigated in the African penguin (Spheniscus demersus), a monogamous and territorial seabird. Contact calls and ecstatic display songs were recorded from an ex situ colony in 2017 and in 2020. For each vocalisation, we measured 14 spectral and temporal acoustic parameters related to both source and filter components. Two separate leave-one-out cross-validated Discriminant Function Analyses (DFA) were then performed, generating the discriminant functions from the vocalisations collected in 2017 to classify those recorded in 2020. The DFA correctly classified 62% of the contact calls (10 subjects) and 80.9% of the ecstatic display songs (seven subjects) according to the correct emitter, showing that acoustic cues to individuality encoded in both vocal types remained unchanged over four consecutive breeding seasons. We suggest that, in this monogamous and territorial bird species, individual acoustic stability could be selected for to identify groupmates and neighbours over the years and to help couples to reunite in consecutive breeding seasons, increasing individual fitness.

9 pages, 2 figures, 1 table, supporting information https://doi.org/10.1002/ece3.7431.-- Data availability statement: Raw and analyzed data supporting the results are stored at the official repository of Monash University and are available at https://doi.org/10.26180/12847661, The extrinsic and intrinsic factors affecting differing reproductive strategies among populations are central to understanding population and evolutionary ecology. To evaluate whether individual reproductive strategies responded to annual patterns in marine productivity and age-related processes in a seabird we used a long term (2003–2013), a continuous dataset on nest occupancy and attendance at the colony by little penguins (Eudyptula minor) at Phillip Island (Victoria, Australia). We found that concurrent with a secondary annual peak of marine productivity, a secondary peak in colony attendance and nest occupancy was observed in Autumn (out of the regular breeding season in spring/summer) with individuals showing mating-like behavior. Individuals attending this autumn peak averaged 2.5 years older than those individuals that exclusively bred during spring/summer. Rather than being a naïve response by younger and inexperienced birds misreading environmental cues, our data indicate that the autumn peak attendance is an earlier attempt to breed by older and more experienced penguins. Therefore, we provide strong support for the fundamental prediction of the life-history theory of increasing investment in reproduction with age to maximize lifetime fitness as future survival prospects diminish and experience increases, Funding for the project came from the Australian Research Council Linkage Project grant LP140100404 to AC and RR. FR institution received funding from the Spanish government through the 'Severo Ochoa Centre of Excellence' accreditation (CEX2019-000928-S)