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Studies on sex-specific segregation in foraging and trophic niche have been focused on large and dimorphic seabirds, with less information on small monomorphic species. Here, we used mini-GPS loggers, habitat suitability models, and stable isotopes to assess the foraging movements, at-sea spatial distribution, and trophic ecology of male and female Boyd’s shearwaters Puffinus lherminieri boydi in Raso Islet (16°36’ N, 24°35’ W), Cabo Verde, during the breeding seasons of 2018–2019. The existence of sexual foraging segregation was tested in short and long foraging trips. Females engaged on longer foraging trips, travelling towards more distant and northward regions from the colony when compared to males, especially during long foraging excursions. Spatial overlap within and between sexes was generally low, indicating a sex-specific pattern in the foraging behaviour and spatial distribution of adult breeders. Habitat suitability models revealed a higher importance for chlorophyll a concentration in explaining females’ at-sea distribution during long foraging trips when compared to males, although the most important predictors in explaining adults’ distribution were sea surface temperature and height for short and long excursions, respectively. Stable isotope analysis revealed that both sexes occupied similar isotopic niches and stable isotope mixing models revealed no diet differences. This indicates that Boyd’s shearwaters segregate at the spatial level while foraging but rely on similar food resources. Our results suggest that female-biased nutritional requirements at the onset of chick-rearing may be driving sexual foraging segregation in this population, which depends upon resources from a rather oligotrophic environment.

In this paper we present a natural deposit in Marie-Galante island (French West Indies), Blanchard 2, where historical-period Audubon's shearwater remains dominate the vertebrate assemblage. We combined a study of sediment geometry, a taphonomic analysis of molluscs, crustaceans and vertebrate remains, and direct radiocarbon dating on bird bone to demonstrate that the cave was used as a nesting ground during the island's colonial period. This approach also allows the discussion of the causes leading to the desertion of the site by birds. Finally, we investigate hypotheses regarding the dynamics of Audubon's shearwater nesting during prehistoric and historical times and the impact of anthropogenic phenomenon on these birds.

Cryptic species are often difficult to count and thus protect. Audubon's Shearwater (Puffinus lherminieri) is a cryptic seabird that has disappeared from many colonies, but knowledge of the population's status is incomplete. This paper reviews the survey methods in detail and assesses the status. This species nests or once nested on at least 154 islands in the Caribbean and remains on 137 today, with most habitat just above sea level. Remaining colonies represent 1% of the former breeding area and are remote, with 98 sites lacking any estimate of density. In 16 plots searched on multiple nights using playback, the probability of detection of defended nests was 79 ± 5% (57 of 72 defended nests) in a single night of searching. Pairs were attempting to breed in 54 ± 6% (39 of 72) of defended nests. Average densities, adjusted for missed detections, ranged from 0.6 to 246 defended nests ha−1 (n = 21 colonies, median = 18.5 ha−1, area-weighted mean = 104 ha−1). Using the best data from every colony, a...

A pardela-de-asa-larga (Puffinus lherminieri Lesson 1839) é uma ave marinha tropical que ocorre entre o sul do Canadá e a costa sudeste do Brasil. Puffinus lherminieri é considerado Criticamente Ameaçado na lista vermelha do Brasil principalmente porque ocorre somente em duas localidades, ambas contendo pequenas populações. Porém, muitas ilhas ao longo da costa Brasileira são pouco conhecidas e a descoberta de novas colônias pode ser significativa para a conservação desta espécie. O objetivo deste estudo foi estimar a distribuição geográfica potencial da pardela-de-asa-larga no Brasil, baseada em modelagem de nicho ecológico (MNE) usando o algorítimo Maxent com camadas obtidas do banco de dados ambientais AquaMaps. A MNE foi baseada em 37 registros de áreas de reprodução nas Américas do Norte e Sul. O modelo mostrou uma ampla distribuição potencial, cobrindo a maior parte da costa Atlântica do Brasil e EUA. Quando filtrada para as ilhas ao longo da costa Brasileira o modelo indicou altos níveis de adequação ambiental próximo aos estados de São Paulo, Rio de Janeiro, Espírito Santo e Bahia. Porém, P. lherminieri prefere ilhas em ambientes com água quente e salina. Então, baseado na influência das correntes que atuam na costa Brasileira nós podemos inferir que colônias são mais prováveis de ocorrer em ilhas da costa da Bahia, Espírito Santo e extremo norte do Rio de Janeiro. Estas devem ser intensamente pesquisadas enquanto as ilhas ao sul de Cabo Frio devem ser descartadas. A existência de novas populações pode ter profundos efeitos no estado de conservação desta ave marinha enigmática e raramente vista. Audubon's Shearwater (Puffinus lherminieri Lesson 1839) is a tropical seabird occurring mainly between southern Canada and the southeast coast of Brazil. Puffinus lherminieri is considered Critically Endangered on the Brazilian Red List because it only occurs in two known localities, both of which contain very small populations. However, many offshore islands along the Brazilian coast are poorly known and the discovery of new colonies would be of considerable significance for the conservation of this species. The aim of this study was to estimate the potential geographic distribution of Audubon's Shearwater in Brazil, based on ecological niche model (ENM) using Maxent algorithm with layers obtained from AquaMaps environmental dataset. The ENM was based on 37 records for reproduction areas in North and South America. The model yielded a very broad potential distribution, covering most of the Atlantic coast ranging from Brazil to the US. When filtered for islands along the Brazilian coast, the model indicates higher levels of environmental suitability near the states of São Paulo, Rio de Janeiro, Espírito Santo and Bahia. However, P. lherminieri prefers islands in environments with warm saline water. Thus, based on the influence of currents that act on the Brazilian coast we can infer undiscovered colonies are most likely to occur on islands on coast of Bahia, Espírito Santo and extreme north of the Rio de Janeiro. These should be intensively surveyed while the islands south of Cabo Frio should be discarded. The existence of new populations would have profound effects on the conservation status of this enigmatic and rarely seen seabird.

The extinct species Puffinus parvus Shufeldt of Bermuda is shown to be synonymous with the living taxon Puffinus boydi of the Cape Verde islands. This species occurred on Bermuda throughout the last 400 000 years, during both glacial and interglacial intervals, and into the Holocene up until the arrival of humans when introduced predators evidently caused its extirpation. Subsequently, the island was colonized briefly by the Caribbean species Puffinus lherminieri, which in turn was extirpated from the island in the 20th Century. The indications are that P. boydi successfully outcompeted P. lherminieri on Bermuda until it was removed through human agency, thus closely paralleling the situation documented for two species of Megadyptes penguins in New Zealand. Thus P. lherminieri and P. boydi have long functioned as biological species and should be considered as full species along with the cold-water species Puffinus baroli of the North Atlantic. Restoration efforts for small shearwaters on Bermuda should now focus on P. boydi rather than P. lherminieri. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 699–707.

The breeding success of burrow-nesting seabirds may be influenced by both nest site characteristics and oceanographic conditions influencing food availability at sea. In this study we describe the breeding biology of the winter-breeding Macaronesian shearwater (Puffinus lherminieri baroli), including nest site characteristics and interspecific competition. We also evaluate the possible effects of changing oceanographic conditions on breeding phenology and breeding success. The study was carried out over two breeding seasons on two islands in the North Atlantic Ocean, Cima Islet and Selvagem Grande. Oceanographic characteristics differed between years. On a regional scale, the North Atlantic Oscillation (NAO) index was low and negative in 2011, and on a local scale, birds used areas with significantly lower values of chlorophyll a concentration and significantly higher values of sea surface temperature anomalies. Hatching success was higher in 2012 than in 2011. At both colonies, egg cracking was the main cause of hatching failure, but in 2011 several eggs on Selvagem Grande were deserted. In 2012 birds laid earlier and chicks had longer wings and were heavier. At both colonies, nests that were deeper, were sheltered from prevailing winds and had small chambers and a soil substrate had a higher probability of being used successfully by the birds. Nests occupied solely by Macaronesian shearwaters were much deeper and had less volume than nests shared with other species. Our study suggests that the breeding success of Macaronesian shearwaters is strongly related to nest site characteristics and that at-sea environmental conditions exert a strong influence on reproductive parameters, with birds breeding in a poor year (evaluated in terms of lower marine productivity) laying much later and their chicks growing at a slower rate than in a good year. The influence of nest site characteristics and environmental conditions may be very important for understanding the breeding ecology of Procellariiformes and may help explain the negative population trend of Macaronesian shearwaters.

Audubon’s Shearwater Pufhnus lherminieri is a little known species of petrel. The recent descriptions of a possibly new species (P. atrodorsalis) and a new subspecies (l? 1. colstoni) have suggested that the population breeding on Reunion Island, I! 1. bailloni, may represent a key taxon for understanding the phylogeography of this group in the Indian Ocean. We provide the first detailed information on distribution, abundance, habitat characteristics and breeding biology of the species on Reunion, and assess relationships between the Indian Ocean taxa based on biometrics, coloration characters and patterns of breeding phenology. We also studied the behaviour of the birds on Reunion, paying particular attention to vocalizations. Analysing the parameters that affect calling rate, such as moonlight, season and time, we show that calling activity can be used to estimate colony size. Using this method, we sampled more than half of Reunion Island habitats suitable for Audubon’s Shearwater, and estimate that the breeding population there is between 3000 and 5000 pairs in at least 235 colonies. Compared to other Indian Ocean populations (n = 136 specimens), the analysis of biometrics and coloration characters suggests that three main populations exist (Comoro, Reunion and Seychelles), with birds of Maldives and Amirantes being biometrically inseparable from those of Seychelles, and birds from Aldabra being intermediate between Seychelles and Reunion. The proposed new species, atrodorsalis, also falls in the overlap between Seychelles and Reunion birds, which argues against a full species taxonomic status.

Este artículo contiene 21 páginas, 6 figuras, 5 tablas., Seabirds inhabiting vast water masses provide numerous examples where opposing phenomena, such as natal and breeding philopatry vs. vagility have dug cryptic taxonomic boundaries among closely related taxa. The taxonomy of little shearwaters of the North Atlantic Ocean (Little–Audubon’s shearwater complex, Puffinus assimilis–lherminieri) still remains unclear, and complementary information on non-breeding distributions and at-sea behaviour becomes essential to unravel divergent local adaptations to specific habitats. Using miniaturized light-level geolocators from seven study areas in the North Atlantic, we evaluate the spatial and habitat segregation, estimate the timing of their key life-cycle events and describe the at-sea behaviour of three taxa of these little shearwaters year-round to distinguish ecological patterns and specializations that could ultimately unravel potential lineage divergences. We also assess morphometric data from birds that were breeding at each study area to further discuss potential adaptations to specific habitats. Our results show that, while birds from different taxa segregated in space and habitats, they share ecological plasticity, similar annual phenology and diel foraging behaviour. These ecological inconsistencies, while defining the evolutionary stressors faced by these taxa, do not suggest the existence of three Evolutionary Significant Units. However, they confirm the recent evolutionary divergence among the three little shearwaters of the North Atlantic., We acknowledge the Ministerio de Economía y Competitividad (MINECO), the Fondos FEDER (CGL2009-11278/BOS, CGL2013-42585-P), the EU LIFE Programme (LIFE09 NAT/PT/000041) and the British Ornithologists’ Union for funding.RR was supported by postdoctoral contracts of the Juan de la Cierva (JCI-2012–11848) and PLEAMAR (2017/2349) programs from the Spanish MINECO and the European Maritime and Fisheries Fund (EMFF), respectively, VHP by a postdoctoral fellowship of Fundação para a Ciência e a Tecnologia (FCT; SFRH/BPD/85024/2012) and ZZ by a PhD grant (APIF-2012) from Universitat de Barcelona (Spain).

International audience; An understanding of how environmental changes affect life history traits and populationdynamics is essential for predicting the effects of climate change, managing ecosystems, and determininghow species and habitats can best be preserved. This applies particularly to seabirds, which, as topmarinepredators, are often considered as indicators of marine ecosystem changes. Most studies have sofar been conducted in polar or temperate regions. However, important changes in the functioning of tropicalmarineecosystems have been reported, but the responses of top predators remain poorly known. Thisstudy focused on a tropical seabird, Audubon’s shearwater Puffinus lherminieri, analyzing the relationshipsbetween climate change and the survival of adults, nesting success, and population dynamics. The populationstudied breeds in Martinique, in the south of the Caribbean region, which is strongly influenced by theAmazon and Orinoco rivers. A data set for the period 1995 to 2014 was used to estimate the survival by ageclasses and breeding success and to determine which climate variables most affected demographic parameters.The population dynamics were modeled to predict the future population growth rates in responseto climate change. The annual adult survival rate increased over the last 20 years, currently standing at94% for adult birds more than 6 years old. Adult survival increased with sea surface temperature (SST)during the nonbreeding season as well as with Amazon River discharge, although the latter with a lag of1 year. The effect of SST was explained by the positive relationship between SST and chlorophyll a duringyears of high discharge from the Amazon and Orinoco. The population decreased between 1995 and 2007at a rate of 3% per year and then increased between 2008 and 2014 at a rate of 7% per year. The increasein adult survival observed should continue as temperatures increase in the future, and the populationmodels predicted a stable or increasing population over the next 50 years (λ = 1.018). These results contrastwith the negative effect of increasing SST on seabird populations found in temperate and polar regions,emphasizing the need to study the impact of climate change on tropical seabirds.

As top predators of pelagic food webs, marine birds naturally bioaccumulate essential and non-essential elements. Levels of arsenic (As), cadmium (Cd), copper (Cu), iron (Fe), mercury (Hg), manganese (Mn), selenium (Se) and zinc (Zn) were determined in the liver, kidneys and muscles of three species of marine birds found on Réunion Island: Barau's Petrel (Pterodroma baraui), Audubon's Shearwater (Puffinus lherminieri bailloni) and the White-tailed Tropicbird (Phaethon lepturus). The study of the 89 birds sampled put forth variations of the elemental levels between organs, age groups (juveniles versus adults) and species. Adult Barau's Petrels showed the highest values of Hg and Cd. This study offers a first glimpse of the levels of impregnation of eight trace elements in top predators of the western Indian Ocean and brings answers to certain questions related to the processes of bioaccumulation in marine top predators of the tropical Indian Ocean.Situés au sommet des réseaux trophiques pélagiques, les oiseaux marins bioaccumulent naturellement des éléments essentiels et non-essentiels tout au long de leur vie. La mesure des teneurs en arsenic (As), cadmium (Cd), cuivre (Cu), fer (Fe), mercure (Hg), manganèse (Mn), sélénium (Se) et zinc (Zn) a été effectuée dans le foie, les reins et les muscles de trois espèces d'oiseaux de l'île de La Réunion, le pétrel de Barau (Pterodroma baraui), le puffin de baillon (Puffinus lherminieri bailloni) et le paille-en-queue à brins blancs (Phaethon lepturus). L'étude des 89 oiseaux échantillonnés fait apparaître des variations des teneurs métalliques entre les organes, les classes d'âge (juvéniles vs adultes), ainsi qu'entre les espèces, les pétrels de Barau adultes ayant les plus fortes teneurs en Hg et Cd. Cette étude offre ainsi, un premier aperçu des niveaux d'imprégnation de 8 éléments traces chez des prédateurs supérieurs de l'Océan Indien occidental tropical et propose des éléments de réponses quant aux processus de bioaccumulation chez ces espèces.Ostrich 2007, 78(2): 435–441

SummaryPelagic seabird populations have declined strongly worldwide. In the North Atlantic there was a huge reduction in seabird populations following the European colonization of the Azores, Madeira and Canary archipelagos but information on seabird status and distribution for the subtropical region of Cabo Verde is scarce, unavailable or dispersed in grey literature. We compiled and compared the historical and current distribution of all seabird species breeding in the Cabo Verde archipelago, updated their relative abundance, investigated their inland habitat preferences, and reviewed their threats. Currently, the breeding seabird community in Cabo Verde is composed of Bulwer’s Petrel Bulweria bulwerii, White-faced Storm-petrel Pelagodroma marina aedesorum, Cape Verde Shearwater Calonectris edwardsii, Cape Verde Storm-petrel Hydrobates jabejabe, Cape Verde Petrel Pterodroma feae, Boyd's Shearwater Puffinus lherminieri boydi, Brown Booby Sula leucogaster, and Red-billed Tropicbird Phaethon aethereus. One breeding species is currently extinct, the Magnificent Frigatebird Fregata magnificens. The relative abundance of Cape Verde Shearwater, Boyd’s Shearwater, Cape Verde Petrel, and Cape Verde Storm-petrel was determined from counts of their nocturnal calls in Santo Antão, São Vicente, Santa Luzia, Branco, Raso and São Nicolau. Cape Verde Petrel occurred only on mountainous islands (Santo Antão, São Nicolau, Santiago, and Fogo) from mid-to high elevations. Larger species such as the Cape Verde Shearwater and Boyd’s Shearwater exhibited a wider distribution in the archipelago, occurring close to the coastline but at lower densities on populated islands. Small procellariforms such as the Cape Verde Storm-petrel occurred at high densities only on rat-free islets and in steep areas of main islands where introduced cats and rats are unlikely to occur. The main threats to seabird populations in Cabo Verde range from predation by introduced predators, habitat alteration or destruction, and some residual human persecution.

In recent decades, several seabird populations have declined globally due to anthropogenic activities. In Brazil, 14 seabird species breed at four oceanic islands and one atoll: the Abrolhos, Fernando de Noronha, and Sao Pedro and Sao Paulo (SPSPA) archipelagos; the Trindade/Martin Vaz Islands; and the Atol das Rocas. Seven species are listed as nationally threatened by extinction. This study aimed to present new information on breeding seabird populations in Brazilian oceanic islands, compile all available data previously published and, when possible, to provide updated information on population estimates from censuses carried out sporadically at different islands between 2006 and 2013. Based on new data and the thorough review provided here, of the 35 seabird breeding populations analysed, 14% were increasing (as Red-billed Tropicbird Phaethon aethereus , Magnificent Frigatebird Fregata magnificens and Brown Noddy Anous stolidus in Abrolhos), 11% were decreasing (as Brown Booby Sula leucogaster in Atol das Rocas and Great Frigatebird Fregata minor in Trindade Island), 23% were stable (as White-tailed Tropicbird Phaethon lepturus in Fernando de Noronha and Brown Noddy and Black Noddy Anous minutus in Sao Pedro and Sao Paulo Archipelago), and the remaining 49% were unknown or not possible to evaluate. The Red-footed Booby ( Sula sula ) is locally extinct in Trindade Island, however there are colonies of only a few individuals of other species, such as the Audubon's Shearwater Puffinus lherminieri and Red- billed Tropicbird in Noronha, Black Noddy in Martin Vaz, and Great ( Fregata ariel trinitatis ) and Lesser ( F. m. nicoll i) Frigatebirds in Trindade, that may become extinct soon. Censuses at distinct periods of the breeding cycles and protocols were highly variable, making temporal comparisons difficult. These results indicate an urgent need for long-term studies to improve the scenario to assess seabird population trends based on comparable methodologies, in order to determine trends in the future.

The Cay Sal Bank in The Bahamas is one of the Caribbean region's most important areas for breeding seabirds, but the colonies previously lacked solid estimates. This paper describes results of four visits between 2010 and 2012. The Santaren Channel, used to transit to and from Cay Sal Bank, contained high numbers (6.1 ± 0.4 birds per km2) of seabirds. The Cay Say Bank has at least 117 detectable islands with 484 ha of land area; the most numerous colony was at Elbow Cay (23 ha). Audubon's Shearwaters (Puffinus lherminieri) were breeding at 97 pairs per ha (total: 2,200; 95% CI = 1,650–2,800 pairs), Sooty Terns (Onychoprion fuscatus) at 382 pairs per ha (total: 8,800; 95% CI = 6,900–10,700 pairs), Bridled Terns (Onychoprion anaethetus) at 38 pairs per km coastline (5,829 m coastline; total: 220; 95% CI = 145–295 pairs) and Brown Noddies (Anous stolidus) at 72 pairs per ha (total: 1,609; 95% CI = 1,070–2,250 pairs). The population of Audubon's Shearwaters is among the largest in the world while po...

We analysed mercury levels in the breast feathers of several breeding seabirds – White-tailed Tropicbird (Phaethon lepturus), Audubon’s Shearwater (Puffinus lherminieri), Lesser Noddy (Anous tenuirostris), White Tern (Gygis alba), Sooty Tern (Onychoprion fuscata) and Roseate Tern (Sterna dougallii) – on Aride Island in the Seychelles during three periods between 1996 and 2005. Mercury concentrations tended to be higher in the second sampling period (2002–03) than the first (1996–97), particularly for inshore-feeding species. El Nino events in 1997–99 and 2002–03 might help to explain this pattern, through an increase in mercury bioavailability for seabirds that forage inshore. However, levels of mercury in tissue decreased significantly from the first period (1996–97) to the third period (2004–05) for inshore-foraging species (Lesser Noddy mean ± s.e.: 0.82 ± 0.02 μg g–1 v. 0.53 ± 0.06 μg g–1 respectively) and more wide-ranging, offshore-feeding species (Sooty Tern: 1.16 ± 0.05 v. 0.59 ± 0.04; White-tailed Tropicbird: 1.82 ± 0.05 v. 1.43 ± 0.09). Wide-ranging species of seabirds are more likely to be useful bioindicators at large spatial scales, with such species suggesting a decreasing trend in mercury pollution in the western Indian Ocean.

Summary More extensive collections of subfossil bird bones from Ascension Island in the South Atlantic further confirm that the former seabird populations of the main island were composed of tropical species still present in greatly reduced numbers, mostly on offshore islets. A single specimen of Puffinus lherminieri provides the first fossil evidence of that species from the island. The extinct flightless rail Atlantisia elpenor was the only land bird certainly known to have been native. A femur, apparently from a vagrant individual, is referred to Porphyrula alleni, A specimen of Nycticorax, much smaller than any recent examples of N. nycticorax seen, is either from an unusually small vagrant or possibly indicates an undescribed endemic species.

The Bonin Islands provide breeding habitat for many species of seabird, but detailed information on breeding sites is unavailable. Here, we describe the recent species composition of breeding seabirds on 66 islands. A total of 15 species (Diomedea immutabilis, D. nigripes, Pterodroma hypoleuca, Bulweria bulwerii, Puffinus pacificus, Oceanodroma tristrami, O. matsudairae, Phaethon rubricauda, Sula leucogaster, S. dactylatra, S. sula, Thalasseus bergii, Sterna fuscata, Anous stolidus and A. minutus) was recorded breeding in the Bonin Islands based on field and literature surveys. The sole nesting record of S. sula was on a small island near Haha-jima, where it has failed to breed since a typhoon struck the island. We did not detect Puffinus lherminieri bannermani, although it bred on Kitaiwo-jima before World War II. S. leucogaster was the most widespread species and bred on 39 islands. The second most widespread species was P. pacificus, which bred on 35 islands. There was a positive relationship between species richness and island area. The distribution of breeding sites may be affected by human settlement and introduced species such as feral goats Capra aegagrus. Introduced animals should be controlled to protect the seabird fauna on the islands.

We report the results of a study of light-induced mortality of petrels at Reunion Island which holds two endemic endangered species, Barau’s petrel ( Pterodroma baraui ) and Mascarene petrel ( Pseudobulweria aterrima ), together with an endemic non threatened subspecies of Audubon’s shearwater ( Puffinus lherminieri bailloni ). We collected 2348 birds attracted to lights between January 1996 and December 1999, among which 70% were Barau’s petrels and 29% were Audubon’s shearwaters. We found also three specimens of the very rare Mascarene petrel. Most grounded birds were fledglings (94%). Light-induced mortality was seasonal and linked with the breeding schedule of each species. At least 20–40% of the fledglings of Barau’s petrels produced annually are attracted by lights. Light-induced mortality is a recent perturbation at Reunion Island. Thus, the effects of this disturbance on the population dynamics of these long lived seabirds may be hard to detect at the present time, but they are likely to occur in the near future. Conservation actions are proposed to limit the light-induced mortality together with other actions and long-term studies focused on the most endangered species.

Tropical seabirds have evolved a wide range of breeding regimes to fit with their local environment. The western Indian Ocean shows various oceanic situations, providing opportunities to link variations in breeding phenology with variations of the environment. The breeding seasons of seabirds at Europa Island (Mozambique Channel, western Indian Ocean) are analysed. Three oceanic, tuna-associated species (the sooty tern Sterna fuscata, the red-footed booby Sula sula, and Audubon's shearwater Puffinus lherminieri) breed during austral winter (June–October), whereas the red-tailed tropicbird Phaethon rubricauda breeds during austral summer (November–April). During winter, sea-surface temperatures are the lowest, subtropical waters are the closest to the island, and long-line catches of tunas are important. Thermal fronts occur during winter, in relation to the northward shift of subtropical waters. This is known to be favourable to tunas, and I suggest that the winter breeding of sooty terns, red-footed boobies and Audubon's shearwaters is because of an increase in the abundance of tunas. Geographic variations in the breeding phenology of sooty terns in the western Indian Ocean largely support the hypothesis that sooty terns take advantage of cool subtropical waters, when those waters are within their foraging range. The red-tailed tropicbird is a solitary forager, not associated with tunas. During the chick-rearing period, 40% of the mass of food brought to the chicks consists of dolphin-fishes Coryphaena spp. Those warm water, surface dwelling fishes are known to migrate in relation to sea-surface temperatures. Seasonal changes in the occurrence or vulnerability of dolphin-fish in the Mozambique Channel may have favoured a summer breeding regime in red-tailed tropicbirds at Europa Island. Further studies of the marine life of seabirds are needed to test these hypotheses and to learn more about the foraging ecology of tropical seabirds.

Oceanographic features, such as fronts, eddies, and upwellings, provide important foraging areas for marine predators. These areas serve as important "hotspots" of marine life, by aggregating weakly swimming lower and mid-trophic level species which, in turn, attract foraging predators. Despite the importance of these dynamic features, we lack a comprehensive understanding of how they create foraging habitat for seabirds and other marine predators. In the first part of this dissertation, I review current knowledge of how seabirds use oceanographic features with an emphasis on developing a more mechanistic understanding of these features, and identify important considerations for future studies. I use the findings of this review to inform two field research projects in the Bay of Fundy, Canada and Onslow Bay, North Carolina. In these two projects, I examined seabird abundance and distribution in relation to oceanographic features that occur at different spatial and temporal scales. In the first project, I examined foraging habitat of red-necked phalaropes (Phalaropus lobatus) in relation fine-scale tidal forcing near the Brier Island ledges in the Bay of Fundy. This research demonstrated the importance of biophysical interactions in creating phalarope habitat, and characterized red-necked phalarope habitat in both space and time. In Onslow Bay, I investigated the effects of Gulf Stream fronts and eddies on the abundance and distribution of seabirds using both remotely sensed and in situ data. I used fisheries acoustics surveys to investigate prey distribution within Gulf Stream frontal eddies. I then developed habitat models for the six most commonly sighted species or species groups (Cory's shearwaters, Calonectris diomedea; greater shearwaters (Puffinus gravis; Wilson's storm petrel, Oceanites oceanicus; Audubon's shearwaters, Puffinus lherminieri; black-capped petrels, Pterodrama hasitata; and red and red-necked phalaropes, grouped together as Phalaropus spp.) using multivariate modeling techniques. Gulf Stream frontal eddies influenced the abundance and distribution of seabirds in Onslow Bay, although frontal features were not as important in predicting seabird habitat as demonstrated in previous studies in the South Atlantic Bight. Prey availability in Gulf Stream frontal eddies was highest in eddy cold core regions, particularly in those regions close to the Gulf Stream. Taken together, the results of my dissertation: underscore the importance of conducting standardized surveys to assess dynamic environmental variables; demonstrate the use of multivariate methods to examine seabird foraging in relation to oceanographic features; emphasize the need to evaluate both prey distributions and physical regimes within oceanographic features at depth; and highlight the importance of temporal aspects of oceanographic features, such as the persistence and age of the features, when assessing the role that these features play in creating seabird foraging habitat.

This study is based upon the identification of 336 bird bones from the Fa'ahia archaeological site, Huahine, French Polynesia. The bones represent birds that were killed for their flesh, feathers, or bones by prehistoric Polynesians. The radiocarbon ages of excavated strata at Fa'ahia range from about 1140 ± 90 to 770 ± 90 yr B.P. The bird bones represent 15 species of resident seabirds, 15 species of resident landbirds, four migrant species, and one introduced species. The only extinct seabird is a gull, Larus new species, although locally extirpated seabirds are Puffinus pacificus, Puffinus nativitatis, Puffinus lherminieri, Pterodroma rostrata, Pterodroma alba, Pterodroma arminjoniana, Sula leucogaster, Sula sula, Fregata minor, Fregata ariel, and Anous minutus. Extinct landbirds are Gallirallus new species, Gallicolumba nui, Macropygia arevarevauupa, Vini vidivici, Vini cf. sinotoi, and Aplonis diluvialis. Locally extirpated landbirds are Ardeola striata, Porzana tabuensis, Gallicolumba erythroptera, Ducula galeata, Ducula aurorae, and Acrocephalus caffer. The bones from Fa'ahia increase the seabird and landbird fauna of Huahine, from the historically known 3 to 15 species and from 7 to 18 species, respectively. Thus the number of species from Huahine is even greater than those from nearby Tahiti, which has a much greater land area and elevation. The occurrence of so many extinct or extirpated species of birds at the Fa'ahia site suggests that this site represents a very early phase of human occupation on Huahine, probably no more than 500 years after the first arrival of people on this previously undisturbed island ecosystem.

Breast feathers were used to estimate mercury levels in six marine birds nesting in the tropical western Indian Ocean, i.e. Sooty Tern (Sterna fuscata), Brown Noddy (Anous stolidus), Lesser Noddy (Anous tenuirostris), Audubon Shearwater (Puffinus lherminieri bailloni), Barau's Petrel (Pterodroma baraui) and the White-tailed Tropicbird (Phaethon lepturus). Juveniles consistently showed lower plumage mercury than adults. The lowest mean level was noted in juvenile Sooty Terns from the Glorioso Archipelago (0.05 mu g g(-1)). The highest levels were obtained for adult Barau's Petrels from Reunion Island (0.96 mu g g(-1)). An inter-site analysis of Sooty Tern showed higher mercury levels in birds nesting on Juan de Nova Island. Levels were low in comparison with values reported in the plumage of seabirds worldwide. The potential impacts of the size, the type (fish/ cephalopod) and the origin (epi-/meso-pelagic) of prey on mercury intake in birds are discussed. Although the diet composition of individuals within a species appeared to be quite variable, combining results on mercury levels with common knowledge of each species allowed additional information on their dietary and foraging habits to be unraveled. (C) 2007 Elsevier B.V. All rights reserved.

International audience; Seabird tissues collected between 2002 and 2004 from Barau's Petrel (Pterodroma baraui), Audubon's Shearwater (Puffinus lherminieri bailloni) and White-tailed Tropicbird (Phaethon lepturus) colonies on Reunion Island were analyzed for metallothioneins (MTs) and trace element content. The subcellular distribution between soluble and insoluble fractions of Cd, Cu, Fe, Mn, Se and Zn was determined in liver and kidney tissues. In both tissues, the soluble fraction of the cell concentrated most of the Cd and Se, whereas Fe, Mn and Zn were preferentially accumulated in the insoluble fraction. The distribution of these elements varied with the tissue, the age of the bird and the species. Furthermore, the distributions of Fe and Mn were somewhat influenced by the bird's physical condition. Metallothionein levels were measured in the soluble fraction after heat denaturation. The levels of these proteins varied from 5.5 ± 2.7 mg.g−1 d.w. to 11.4 ± 6.2 mg.g−1 d.w., depending on the species and the tissue considered. Metallothionein levels were significantly different between liver and kidney only in the White-tailed Tropicbird. In the three species, MT levels in kidney were significantly higher in adults than in juveniles. The bird's weight also had an influence on hepatic and renal MT levels, but not the gender nor the reproductive status. The implication of MTs in Cu and Zn homeostasis, and Cd and Hg detoxification are discussed. In addition, clues on Hg regulation by Se were found, especially in Barau's Petrel, where the levels of these two elements were very significantly correlated.