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Owning a nest is a prerequisite for breeding in Procellariiform seabirds, which can leave their single egg and/or chick unattended for long periods and show high nest fidelity. However, the determinants of nest fidelity vary among species. Amongst them, Bulwer’s Petrel Bulweria bulwerii lays the biggest egg relative to body size within the Family Procellariidae. Therefore, individuals should choose their nests carefully and change essentially if they can improve their reproductive performances. This study conducted on Vila islet, Azores, aimed to determine why Bulwer’s Petrels actually change nest. Nest fidelity exceeded 85%. Nest changes were most likely to occur after a breeding failure or a non-breeding year, but they did not allow improving breeding success and they often resulted in missed breeding years. On average, the new nests were not of higher quality than the old ones, except for the individuals whose first breeding attempt in the new nest was successful. In addition, the quality of the new nest was unrelated to the number of skipped years and to the distance moved. Almost half of changes occurred towards neighbouring nests. They were associated with a lower probability to skip years. Therefore, Bulwer’s Petrels might prioritize proximity over nest quality to reduce the costs of nest changes. communities. This study was part of the project PTDC/BIA-BDE/67286/2006 funded by FCT and by FEDER through the Programme COMPETE (Ref: FCOMP-01-0124-FEDER-007061). The Programmes ‘MARE’ (Integrated Management of Coastal and Marine Sites of the Azores, Life contract B4-3200/98-509), ‘OGAMP’ (Planning and Management of Marine Protected Areas, Interreg IIIB-MAC/4.2/A2), ‘MARMAC’ (Knowledge, Promotion and Valorization for a Sustainable Utilization of Marine Protected Areas in Macaronesia, Interreg IIIB/FEDER/MARMAC/003-4/2005-6 and Interreg IIIB-05/MAC/4.2/A4), and MoniAves, all coordinated by R.S. Santos, also provided support for fieldwork. IMAR-DOP/UAc is funded by FCT and DRCT-Azores as Research Unit 531 and Associate Laboratory 9 (ISR-Lisbon). info:eu-repo/semantics/publishedVersion

Trophic networks in small isolated islands are in a fragile balance, and their disturbance can easily contribute toward the extinction vortex of species. Here, we show, in a small Atlantic island (Raso) in the Cabo Verde Archipelago, using DNA metabarcoding, the extent of trophic dependence of the Endangered giant wall gecko Tarentola gigas on endemic populations of vertebrates, including one of the rarest bird species of the world, the Critically Endangered Raso lark Alauda razae. We found that the Raso lark (27%), Iago sparrow Passer iagoensis (12%), Bulwer's petrel Bulweria bulwerii (15%), and the Cabo Verde shearwater Calonectris edwardsii (10%) are the most frequent vertebrate signatures found in the feces of the giant wall gecko. This work provides the first integrative assessment of their trophic links, an important issue to be considered for the long‐term conservation of these small and isolated island ecosystems.

Invasive ants have the potential to cause severe impacts on the structure and composition of native invertebrate communities and interfere with the natural processes of pollination and seed dispersal. Less frequently reported, direct and indirect impacts on vertebrates, namely birds, are also known to occur. The Argentine ant Linepithema humile is one of the worst invasive species worldwide, and is responsible for economic and ecological impacts in Madeira since its introduction. Previous reports indicated that Argentine ants may be a frequent predator of nestlings on the Desertas Islands which harbour internationally important seabird colonies. Here, we provide a survey of the records of bird predation by Argentine ants in the Desertas. Furthermore, we also assessed if these invasive ants affected the most abundant crevice-nesting seabird on Deserta Grande, the Bulwer’s petrel Bulweria bulwerii, by nest monitoring in the years of 2014–2016. We found that breeding success varied annually between 0.56 and 0.63 chicks produced per nesting attempt. Ant predation of chicks was observed in only two out of 294 study nests. Furthermore, no relationship was found between local abundance of Argentine ants and breeding success of Bulwer’s petrels. We conclude that Argentine ants do not seem to pose a major threat to nesting petrels on the Desertas, although we acknowledge the possibility that environmental changes and episodic population explosions of this invasive species may lead to a greater impact on seabirds’ reproductive success. European Regional Development Fund through Program LIFE Recover Natura; Fundação para a Ciência e a Tecnologia (FCT) info:eu-repo/semantics/publishedVersion

Existe informação suplementar disponível na versão online. The lunar cycle is believed to strongly influence the vertical distribution of many oceanic taxa, with implications for the foraging behaviour of nocturnal marine predators. Most studies to date testing lunar effects on foraging have focused on predator activity at-sea, with some birds and marine mammals demonstrating contrasting behavioural patterns, depending on the lunar-phase. However, to date no study has focused on how the lunar cycle might actually affect predator-prey interactions in the upper layers of the ocean. Here, we tested whether the diet of the predominantly nocturnal pelagic predator, the Bulwer's petrel (Bulweria bulwerii) would change throughout the lunar cycle, using molecular analysis to augment detection and taxonomic resolution of prey collected from stomach-contents. We found no evidence of dietary shifts in species composition or diversity, with Bulwer's petrel always consuming a wide range of mesopelagic species. Other co-variables potentially affecting light availability at-sea, such as percentage of cloud cover, did not confound our results. Moreover, many of the species found are thought not to reach the sea-surface. Our findings reveal that nocturnal predators are probably more specialized than previously assumed, irrespective of ambient-light, but also reveal deficiencies in our current understanding of species vertical distribution and predation-dynamics at-sea. Fundação para a Ciência e a Tecnologia (FCT); FEDER info:eu-repo/semantics/publishedVersion

AIM: Our current understanding of migratory strategies and the reasons for their high variability along the phylogenetic tree remains relatively poor. Most of the hypotheses relating to migration have been formulated for terrestrial taxa; classically, oceanic migrations were considered as merely dispersive because of the scarcity of observations in the open ocean. We describe for the first time, the migration strategy of a small seabird, the Bulwer's petrel (Bulweria bulwerii), and provide new insights into the ecology and evolution of long-distance marine migrations. LOCATION: Subtropical and tropical Atlantic Ocean. METHODS: Using cutting-edge geolocators, we examined the year-round distribution and at-sea activity patterns of adult Bulwer's petrels sampled at five localities throughout the species' breeding range in the Atlantic, within the Azores, Salvages, Canary and Cape Verde archipelagos. We assessed the migratory connectivity of the species and its habitat use at population and metapopulation scales. RESULTS: Our results provide the first evidence of an oriented leapfrog migration in oceanic seabirds. Ecological niche models based on breeding-season data effectively predicted that subtropical waters of the South Atlantic would be the preferred habitat for the northern populations of Bulwer's petrels during the non-breeding season. Habitat modelling also highlighted similarities in distributions between the breeding and non-breeding periods for the southern populations. Data on at-sea activity patterns suggested that birds from the northern and southern populations behave differently during the breeding season, as well as in the northern and southern non-breeding ranges during the non-breeding period. MAIN CONCLUSIONS: These results indicate that specific habitat preferences, presumably related to differences in prey availability, explain the observed distributions and hence the pattern of leapfrog migration described for Bulwer's petrel. Our study demonstrates the utility of integrating diverse tracking data from multiple populations across international boundaries, and habitat modelling, for identifying important areas common to many marine species in the vast oceanic environments. FEDER (CGL2009-11278/BOS); SEO/BirdLife (project LIFE+INDEMARES: LIFE07NAT/E/000732) info:eu-repo/semantics/publishedVersion

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La croissance pondérale et staturale des poussins de Pétrels de Bulwer, Bulweria bulwerii, de Selvagem Grande (30º09’N, 15°52’W) ne diffère en rien de ce qui est habituel chez les Procellariidés. A partir d’un poids à la naissance un peu inférieur au poids de l’oeuf. Une croissance rapide puis ralentie amène les poussins à un poids maximum supérieur au poids de l’adulte. Par la suite, le poids corporel s’abaisse et, à l’envol, ii est un peu inférieur à celui des adultes. La croissance de l’aile, lente avant la pousse des rémiges, puis rapide. Ne s’achève qu’au moment de l’envol. La croissance du culmen et celle du tarse, d’abord rapides puis ralenties s’achèvent respectivement aux environs des deux-tiers et de la moitié du séjour au nid des poussins. La fréquence des repas est à peu près constante pendant toute la période d’accroissement pondéral. Il est probable qu’elle diminue par la suite. Le poids du repas augmente rapidement pendant la première décade de la vie, puis diminue très lentement. Dans ces conditions, la quantité de nourriture consommée quotidiennement augmente pendant la première décade, reste à peu près constante pendant les trois suivantes, puis décroit. Au total, un poussin aura consommé au cours de sa croissance un peu plus de 0,5 kg de nourriture, dont une partie sous forme d’huile stomacale, ce qui semble correspondre à un prélèvement en mer de 1,5 kg, soit environ 17% de la consommation familiale pendant la même période. ABSTRACT: The growth of the chicks of the Bulwer’s Petrel, Bulweria bulwerii, on Selvagem Grande (30º09’N, 15°52’W) shows no differences with what is usual among Procellariidae. The weight at birth is slightly lower than that of the egg. The subsequent increase, rapid at the beginning, slows down, and a maximum weight higher than the adult weight is reached. Later on the body weight lowers and, at fledging, is slightly lower than that of the adult. The wing grows slowly before the appearance of the remiges, then rapidly, and stops at fledging. The growth of the culmen and tarsus, rapid at first, slows down and stops respectively at the two thirds and at half of the chick sojourn on the nest. The feeding frequency, is almost constant during the period of weight gain, and probably lessens afterwards. In these conditions the amount of food eaten daily increases during the first decade of life, remains constant during the following three, and lessens afterwords. On the whole, a chick eats during its growth a little more than 0.5 kg of food, part of which as stomach oil, which seems to correspond to a catch of 1.5 kg, or about 17% of the family intake during the same period.