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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.

Two eggs (L29 and N28) were recovered in the Holocene site of Lobos 3, (Islote de Lobos, north Fuerteventura, Canary Islands), the site has been interpreted as a purple dye workshop from the Early Roman Empire Epoch. For the first time, eggs from a Holocene deposit of the Canary Islands have been analyzed in terms of size, shape, and biomineral structure, and studied on the basis of several thin sections and SEM analysis. The analysis of the remains allowed the assignation of both eggs to Procellariidae birds, thanks to the relative proportion of the eggshell layers and the vesiculation patterns. The size of the eggs allowed the assignation of L29 to cf. Calonectris/Puffinus, and to cf. Puffinus for N28. The absence of more structural analysis on Procellariiformes eggshells prevent a more specific assignation. The accumulation pattern of the eggs is compatible with a seasonal occupation pattern of the Roman site., CajaCanarias, European Union "NextGenerationEU"/PRTR, Ministry of Science and Innovation, Spain (MICINN) Spanish Government, Spanish Ministry of Science and Innovation through the Maria de Maeztu' program for Units of Excellence, NextGeneration EU/PRTR, Juan de la Cierva-Formacion

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.

Seabirds, particularly Procellariiformes, are highly mobile organisms with a great capacity for long dispersal, though simultaneously showing high philopatry, two conflicting life‐history traits that may lead to contrasted patterns of genetic population structure. Landmasses were suggested to explain differentiation patterns observed in seabirds, but philopatry, isolation by distance, segregation between breeding and nonbreeding zones, and oceanographic conditions (sea surface temperatures) may also contribute to differentiation patterns. To our knowledge, no study has simultaneously contrasted the multiple factors contributing to the diversification of seabird species, especially in the gray zone of speciation. We conducted a multilocus phylogeographic study on a widespread seabird species complex, the little shearwater complex, showing highly homogeneous morphology, which led to considerable taxonomic debate. We sequenced three mitochondrial and six nuclear markers on all extant populations from the Atlantic (lherminieri) and Indian Oceans (bailloni), that is, five nominal lineages from 13 populations, along with one population from the eastern Pacific Ocean (representing the dichrous lineage). We found sharp differentiation among populations separated by the African continent with both mitochondrial and nuclear markers, while only mitochondrial markers allowed characterizing the five nominal lineages. No differentiation could be detected within these five lineages, questioning the strong level of philopatry showed by these shearwaters. Finally, we propose that Atlantic populations likely originated from the Indian Ocean. Within the Atlantic, a stepping‐stone process accounts for the current distribution. Based on our divergence time estimates, we suggest that the observed pattern of differentiation mostly resulted from historical and current variation in sea surface temperatures., We conducted a multilocus phylogeographic study on a widespread shearwater and sequenced three mitochondrial and six nuclear markers on all extant populations. We found sharp differentiation among populations separated by the African continent with both markers, while only mitochondrial markers allowed characterizing the five nominal lineages. We propose that Atlantic populations originated from the Indian Ocean. Within the Atlantic, a stepping‐stone process accounts for the current distribution.

International audience; The eradication of invasive mammals on islands is important for protecting seabird populations and insular ecosystems. However, the impacts of such eradications are insufficiently known because monitoring of potentially beneficiary species is often sporadic and limited. We performed a survey of all seabird species on Saint-Paul Island, southern Indian Ocean, 20 years after successful eradication of invasive black rat (Rattus rattus) and European rabbit (Oryctolagus cuniculus). Using complementary sampling designs including adaptive cluster sampling, stratified random sampling and entire sampling, we estimated population changes and colonization by new seabird species. A total of 13 seabird species were found breeding on Saint-Paul post-eradication compared to six before the eradication. Among the seven species that colonized the island, five (MacGillivray’s prion Pachyptila macgillivrayi, fairy prion P. turtur, white-bellied storm petrel Fregetta grallaria, Antarctic tern Sterna vittata, sooty tern Onychoprion fuscatus) had relictual populations breeding on a nearby islet, and one (brown skua Catharacta antarctica) was a new breeding species. We also found breeding subantarctic little shearwaters Puffinus elegans. For species that were breeding on the Saint Paul pre-eradication, the mean annual population growth rate was 1.030 ± 0.093 (SE). Species known to be vulnerable to rat predation (prions, great-winged petrel Pterodroma macroptera, flesh-footed shearwater Puffinus carneipes, subantarctic little shearwater, white-bellied storm petrel, Antarctic tern) had the highest population growth rates. Two decades after the eradication of invasive mammals on a remote oceanic island, seabird populations were high beneficiaries. These findings further highlight the importance of invasive mammal eradication on islands as a conservation tool. Results are encouraging for the planned eradication of invasive mammals from nearby Amsterdam Island, and suggest this will mainly benefit terns and small burrowing petrels.

Erysipelothrix rhusiopathiae, the causative agent of the disease erysipelas, is a gram-positive bacillus, and an opportunistic pathogen in diverse species of animals. In New Zealand, E. rhusiopathiae has killed endangered birds on offshore islands, including Kākāpō (Strigops habroptilus), Takahē (Porphyrio hochstetteri), and Kiwi (Apteryx spp.). The source of infection is uncertain, and the prevalence of E. rhusiopathiae among wild birds is currently unknown. During October 2018 to December 2018, we surveyed dead and live seabirds that visit two of New Zealand's offshore islands used for Kākāpō conservation with the goal of determining the prevalence of E. rhusiopathiae. Bone marrow from dead birds was cultivated on selective agar, and organisms cultured were identified using matrix-assisted laser desorption/ionization with time-of-flight mass spectrometry. The prevalence of E. rhusiopathiae was calculated in different species for each island. We surveyed live birds using PCR with Erysipelothrix spp.-specific primers on blood samples. The prevalence of E. rhusiopathiae in dead seabirds on Whenua Hou and Te Hauturu-o-Toi was 3.4% (3/86) and 11.4% (5/44), respectively. On Whenua Hou, E. rhusiopathiae was detected in Sooty Shearwaters (Puffinus griseus; 5.9%, 2/34) and Mottled Petrels (Pterodroma inexpectata; 2.7%, 1/36) while it was detected only in Cook's Petrels (Pterodroma cookie; 13.5%, 5/37) on Te Hauturu-o-Toi. Blood samples were collected from two seabird species; only one of 50 Mottled Petrels (2.0%) was positive for the presence of Erysipelothrix spp. Our findings confirm that burrowing seabirds are possible reservoirs of E. rhusiopathiae on both islands studied and may be the source of spillover to other species on the island. The differences in observed prevalence suggest the species composition of the reservoir of E. rhusiopathiae may vary geographically.

We investigated how foraging habits vary among three ecologically distinct wide-ranging seabirds. Using amino acid δ15N proxies for nutrient regime (δ15NPhe) and trophic position (Δδ15NGlu-Phe), we compared Newell’s shearwater (Puffinus newelli) and Laysan albatross (Phoebastria immutabilis) foraging habits over the past 50–100 years, respectively, to published records for the Hawaiian petrel (Pterodroma sandwichensis). Standard ellipses constructed from the isotope proxies show that inter-population and interspecific foraging segregation have persisted for several decades. We found no evidence of a shift in nutrient regime at the base of the food web for the three species. However, our data identify a trophic decline during the past century for Newell’s shearwater and Laysan albatross (probability ≥ 0.97), echoing a similar decline observed in the Hawaiian petrel. During this time, Newell’s shearwaters and Hawaiian petrels have experienced population declines and Laysan albatross has experienced range extension and apparent population stability. Counting other recent studies, a pattern of trophic decline over the past century has now been identified in eight species of pelagic seabirds that breed in the Hawaiian Islands. Because our study species forage broadly across the North Pacific Ocean and differ in morphological and behavioral traits and feeding methods, the identified trophic declines suggest a pervasive shift in food web architecture within the past century.

Seabirds care for their offspring in remote breeding colonies where foraging sites are distant and may be unpredictable, and where chicks are left unaccompanied for extended periods during their parents’ foraging trips, leaving them vulnerable to predation or starvation. One way to mitigate this risk is for individuals to coordinate parenting duties with their partner. Many biparental and cooperatively breeding species are now known to coordinate their care, though the mechanisms underlying this are not well understood. In Manx shearwaters (Puffinus puffinus), both parents alternate shifts of incubation in a coordinated manner. To resolve which processes may underlie this routine, we imposed a wing-loading handicap on parents to reduce their foraging efficiency, forcing them to choose between an extended foraging trip or to return to the nest before their condition has recovered to optimal levels. We found that handicapped parents took significantly longer trips than normal, to which their partner responded by lengthening their incubation shift, suggesting shift durations are not pre-determined. However, the duration of foraging trips and the mass at which foraging birds returned to the nest appeared to be mediated by the condition of the partner. These results suggest that while foraging trip duration is largely driven by the need for the foraging bird to recoup its own condition losses, information-transfer between the parents may facilitate a more cooperative mechanism whereby the decisions made by foraging birds still account for the condition of their partner.

10 pages, 4 figures.-- Data availability: All relevant data are publicly available in the Seabird Tracking Database: http://seabirdtracking.org/mapper/?dataset_id=879 and http://seabirdtracking.org/mapper/?dataset_id=1409, Foraging distribution of flying seabirds is constrained by environmental factors influencing individual decision-making. This must be particularly true during the breeding period, when individuals face additional limitations imposed by their central-place foraging behaviour. We used GPS data loggers and Argos PTTs to track the foraging flights of Balearic shearwaters (Puffinus mauretanicus) during the chick-rearing period of 2011–2014 in the Balearic Islands (Western Mediterranean). We identified main areas used by tracked birds and characterised their productivity patterns. Based on a spatial seascape approach of flight costs varying with time, shaped by environmental processes as winds, we also estimated flight costs to reach foraging grounds in outward and return trips from the colony. Individuals repeatedly used the closest areas on the Iberian continental shelf. However, sporadic and favourable wind conditions facilitated low-cost flight to more distant and equally productive areas of the western North African shelf, Funding support was provided to LPO and SEO/BirdLife through Interreg project FAME, LIFE + project INDEMARES, and the Ibiza Preservation Fund, and to the IEO through a Marie Curie Career Integration Grant (CONPELHAB; PCIG09-GA-2011-293774). ML was funded by a Juan de la Cierva (JCI-2010-07639) and a Ramón y Cajal (RYC-2012-09897) postdoctoral contract. FR was funded by a Juan de la Cierva (JCI-2015-24531) postdoctoral contract, With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)

Islands worldwide have sufered seabird extinctions after the arrival of humans and the alien species they introduced. On Santa Luzia (Cabo Verde), an uninhabited island of 35 km2 ,the presence of an impressive quantity of petrel bones in coastal dunes suggested the previous existence of an important seabird colony. Yet, these remains had not been identifed and no seabird extinctions have been reported for the island. This paper characterizes the extinct seabird colony of Santa Luzia and discusses the chronology and possible causes of its demise. A total of 130 grid points in a 5 km2 area and 38 supplementary points within and outside the main study area were excavated to collect bone remains. A total of 1318 anatomical elements, identifed as White-faced Storm Petrel Pelagodroma marina eadesorum (85.3% of the minimum number of individuals, MNI), Boyd’s Shearwater Pufnus lherminieri boydi (11.8% MNI) and Cape Verde Storm Petrel Hydrobates jabejabe (2.9% MNI), were found in 18% of the sampling points, within 1.25 km2 . Neither of the two former species currently breeds on Santa Luzia. In addition, two bones of the Cape Verde Shearwater Calonectris edwardsii and Pterodroma sp. were detected in the supplementary points. Radiocarbon dating of White-faced Storm Petrel (n=10) and Boyd’s Shearwater bones (n=13) suggests that the colony probably went extinct during the frst half of the twentieth century. The recent extinction of these species on Santa Luzia might be consequent on the arrival of humans and their domestic animals on the island. We estimate that the extinct seabird populations must have been at least hundreds of thousand strong, far larger than current populations of the same species in Cabo Verde. We suggest that, following feral cat eradication, Santa Luzia has a signifcant potential for seabird restoration Fundação para a Ciência e Tecnologia - FCT info:eu-repo/semantics/publishedVersion

Increasing human activities have detrimental consequences on marine ecosystems and their impact can have cumulative effects. Within marine ecosystems, seabirds respond to ecosystem variability and face multiple human pressures, especially threatened species. In long-lived species, juveniles and immatures could represent up to 50% of the total population, but their migratory movements remain largely unknown. Here, we depict the migratory patterns of juvenile Balearic shearwaters Puffinus mauretanicus, the most threatened European seabird, using miniaturised satellite transmitters. At the end of the 2012 breeding season, five tagged juveniles left the breeding colonies of Eivissa Island (western Mediterranean) the first week of July. They moved westwards to reach the Atlantic Ocean between 3 and 13 days afterwards. Juveniles showed a twophase migratory pattern: they first travelled slower close to the breeding colonies, and then moved towards their wintering areas in the Atlantic Ocean by rapid directional movements. Environmental cues (e.g.,marine productivity, water mass distribution, frontal systems) might have a prominent role in driving the migratory patterns of juvenile Balearic shearwaters, moving from warm and poor marine areas in the Mediterranean Sea to cooler and rich non-breeding grounds in the Atlantic Ocean. Based on observational findings, we observed certain spatial overlap of juvenile Balearic shearwaters with areas of high human impact, but the relationship between flying travel speed and both fishing effort and cumulative human impacts were not statistically significant. These results suggest that more research is needed to assess whether the movement patterns of migrating juveniles are affected by human activities. Therefore, understanding the at-sea spatial ecology of juveniles should be a priority for research and conservation due to the importance of this population component in long-lived species, as well as assessing their vulnerability to multiple anthropogenic pressures

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).

Aim Europe's only globally critically endangered seabird, the Balearic shearwater (Puffinus mauretanicus), is thought to have expanded its postbreeding range northwards into UK waters, though its at sea distribution there is not yet well understood. This study aims to identify environmental factors associated with the species’ presence, map the probability of presence of the species across the western English Channel and southern Celtic Sea, and estimate the number of individuals in this area. Location The western English Channel and southern Celtic Sea. Methods This study analyses strip transect data collected between 2013 and 2017 from vessel‐based surveys in the western English Channel and southern Celtic Sea during the Balearic shearwater's postbreeding period. Using environmental data collected directly and from remote sensors both Generalized Additive Models and the Random Forest machine learning model were used to determine shearwater presence at different locations. Abundance was estimated separately using a density multiplication approach. Results Both models indicated that oceanographic features were better predictors of shearwater presence than fish abundance. Seafloor aspect, sea surface temperature, depth, salinity, and maximum current speed were the most important predictors. The estimated number of Balearic shearwaters in the prediction area ranged from 652 birds in 2017 to 6,904 birds in 2014. Main conclusions Areas with consistently high probabilities of shearwater presence were identified at the Celtic Sea front. Our estimates suggest that the study area in southwest Britain supports between 2% and 23% of the global population of Balearic shearwaters. Based on the timing of the surveys (mainly in October), it is probable that most of the sighted shearwaters were immatures. This study provides the most complete understanding of Balearic shearwater distribution in UK waters available to date, information that will help inform any future conservation actions concerning this endangered species., Areas with consistently high probabilities of shearwater presence were identified at the Celtic Sea front. Our estimates suggest that the study area in southwest Britain supports between 2% and 23% of the global population of Balearic shearwaters. This study provides the most complete understanding of Balearic shearwater distribution in UK waters available to date, information that will help inform any future UK conservation actions concerning this endangered species.

In migratory animals for whom post-natal care is limited, it is essential that there are inherited mechanisms whereby an individual can navigate—first, to the terminus of their migration, and second, back to a suitable breeding site. In birds, empirical evidence suggests that orientation on first migration is controlled by an inherited navigational vector, a direction and a distance in which to move (the “clock and compass” model) [1, 2, 3, 4, 5]. The mechanism and information that underlie the return to the natal breeding site are, however, almost entirely unknown. A potential solution to this problem would be for an animal to learn the values for spatially and temporally stable gradient cues that specifically indicate the location of the natal site [6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16]. One potential cue for latitude is magnetic inclination. Here, we use ringing recoveries made over the last 80 years to investigate whether magnetic inclination might be used as a navigational cue to control the latitude of recruitment in a trans-global migrant, the Manx shearwater (Puffinus puffinus). We find that small changes in inclination between when a bird fledges and when it returns from first migration correlate with probabilistic changes in latitude at recruitment, in doing so quantitatively fulfilling a priori predictions as to the magnitude and direction of latitudinal shift. This, we believe, suggests that (1) natal magnetic inclination is learnt prior to fledging and (2) is used to provide latitudinal information when making the first return trip from the wintering grounds.

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.

The endangered Hawaiian petrel (Pterodroma sandwichensis) is endemic to the main Hawaiian Islands and has undergone a breeding range contraction since the arrival of humans. Using abiotic and biotic environmental variables, we developed a terrestrial habitat suitability model for the species on the island of Kauai based on contemporary sites where the species is known (or strongly suspected) to nest, as well as a habitat/threat-isolation index that combined predictions from this suitability model with spatial information on two anthropogenic threats to the species. After accounting for large-scale relative spatial positioning of sites in modeling procedures, the habitat suitability model suggests that the probability that a location on Kauai could be suitable for Hawaiian petrel nesting activity increases with increasing mean annual wind speed, and may also increase somewhat with increasing slope and native vegetation cover. The habitat suitability model (which does not incorporate spatial information on anthropogenic threats to the species) predicts approximately 74 km2 of Kauai, mostly in the interior of the island, as being potentially suitable with predicted probability > 0.7 for Hawaiian petrel terrestrial activity, and about 35 km2 with predicted probability > 0.9. Encouragingly, almost 50 km2 of land with predicted probability > 0.7 and almost 24 km2 with predicted probability > 0.9 is currently protected, being located on either government or private reserve land. Based on the habitat/threat-isolation index, most land predicted to be both suitable (based on environmental variables) and as isolated from threats as a large number of the known contemporary Hawaiian petrel sites, is found in government and private reserves. Some degree of predicted habitat overlap between the Hawaiian petrel and Newell’s shearwater (Puffinus newelli), another Hawaiian seabird of conservation concern, suggests that some of the same larger tracts of land could potentially be managed jointly for both species, as currently done in Upper Limahuli Preserve and Hono O Na Pali Natural Area Reserve on Kauai.

The island of Kaua‘i, Hawaii, USA, holds a large breeding populations of the endangered Hawaiian Petrel (Pterodroma sandwichensis) and a majority of the world population of the threatened Newell's Shearwater (Puffinus newelli). We evaluated island-wide population trends of both species. For Newell's Shearwaters, we considered radar counts at 13 sites between 1993 and 2013 and annual island-wide tallies of fledglings retrieved after being grounded by light attraction in 1979–2015 (Save Our Shearwaters [SOS] program). For Hawaiian Petrels, we considered radar counts alone. Radar data indicated a 78% decline overall in numbers of Hawaiian Petrels (at an average rate of ∼6% per year) and a 94% decline overall in numbers of Newell's Shearwaters (at an average rate of ∼13% per year) during the survey period. Most (92%) radar sites showed significant declines of Newell's Shearwaters across the entire survey period, as did 62% of sites for Hawaiian Petrels. The SOS recovery effort collected 30,522 Newell...

Capsule: Playback with dual-sex calls increases the response rate of Manx Shearwaters Puffinus puffinus by 40–60% and reduces its daily variability, which would improve the precision of population estimates.Aims: To test whether playing male and female calls would elicit more responses to playback than male-only calls, reduce daily variability and the length of response rate calibration trials, and give more precise estimates. We also measured response times to playback and assessed the reliability of visual signs of occupancy at burrow entrances.Methods: Responses to four playback call-types (male-only and three variants of dual-sex calls) were compared in repeated trials at two colonies (Ramsey and Rum, UK) during May–June 2014.Results: Dual-sex calls gave higher response rates with lower variance than male-only calls, because females frequently replied to female calls but rarely to male calls. In simulated 3–5-day calibration trials, response rates and correction factors were up to 50% more pre...

Moku‘ae‘ae Rock Islet is located off the north shore of Kaua‘i and is protected as a Hawai‘i State Seabird Sanctuary. In the late 1970s it was also the site of a cross-fostering project for the endangered Newell’s Shearwater, Puffinus newelli . Few avifauna surveys have been undertaken on the islet, and none since 2007. In 2013 and 2015, we conducted burrow searches across the entire islet to obtain breeding population estimates for each species and to evaluate whether the Newell’s Shearwater had become established as a breeding species after the cross-fostering project. Auditory surveys were also conducted for 2 hr after sunset and 1.5 hr before sunrise, which are the peak calling periods for the Newell’s Shearwater on Kaua‘i. A total of seven seabird species was recorded on the islet, of which three, Bulwer’s Petrel, Bulweria bulwerii ; Wedge-tailed Shearwater, Ardenna pacifica ; and Red-tailed Tropicbird, Phaethon rubricauda , were confirmed breeding. This is the first time Bulwer’s Petrel has been confirmed breeding on Moku‘ae‘ae. Searches for Newell’s Shearwater did not produce evidence that this species breeds on the islet, suggesting that the cross-fostering project was not successful. Although the islet is small, it represents an important refuge for seabird species. However, high levels of depredation were recorded on Bulwer’s Petrel; we conclude that these were all killed by the introduced Barn Owl, Tyto alba , based on disposition of the bodies and the injuries they had sustained. Management recommendations for the islet include creation of a management plan, annual breeding bird surveys, annual rat monitoring, and Barn Owl control.

Este artículo contiene 13 páginas, 5 figuras, 1 tabla., Patterns of behavioural variation and migratory connectivity are important characteristics of populations, particularly at the edges of species distributions, where processes involved in influencing evolutionary trajectories, such as divergence, mutual persistence, and natural hybridization, can occur. Here, we focused on two closely related seabird species that breed in the Mediterranean: Balearic shearwaters (Puffinus mauretanicus) and Yelkouan shearwaters (Puffinus yelkouan). Genetic and phenotypic evidence of hybridization between the two species on Menorca (the eastern and westernmost island in the breeding ranges of the two shearwaters, respectively) has provided important insights into relationships between these recently diverged species. Nevertheless, levels of behavioural and ecological differentiation amongst these populations remain largely unknown. Using geolocation and stable isotopes, we compared the at-sea movement behaviour of birds from the Menorcan ‘hybrid’ population with the nearest neighbouring populations of Balearic and Yelkouan shearwaters. The Menorcan population displayed a suite of behavioural features intermediate to those seen in the two species (including migration strategies, breeding season movements and limited data on phenology). Our findings provide new evidence to support suggestions that the Menorcan population is admixed, and indicate a role of non-breeding behaviours in the evolutionary trajectories of Puffinus shearwaters in the Mediterranean., This study was funded by the Natural Environment Research Council, UK (grant numbers: NE/J500227/1, EK192-02/12).The National Oceanography Centre, the Total Foundation and Merton College – University of Oxford provided additional support. The Yelkouan shearwater project was funded by the French Biodiversity Agency for Marine Protected Areas within the ‘Programme PACOMM, Natura2000 en mer’. MG is supported by the Spanish Ministry of Science (CGL2017-85210).

The global phylogenetic relationships of the extinct Scarlett’s Shearwater (Puffinus spelaeus) from New Zealand are examined using ancient DNA sequencing and phylogenetic analyses. The cytochrome b sequences obtained confirm the distinctiveness of this taxon. It forms a strongly-supported clade with two other New Zealand species, suggesting a radiation of similar-sized species in this region. Molecular dating suggests Pleistocene divergences within this clade.

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...

This study presents the first data on trace element and organic pollutant concentrations in the Critically Endangered Balearic shearwater Puffinus mauretanicus collected in 2010 and 2011 in Portugal. Trace element levels were below the threshold levels for adverse effects on birds, despite the Hg concentrations in feathers (4.35μg·g-1ww). No significant differences were detected between individuals from 2010 and 2011 except for Se concentrations in liver, feathers and muscle (higher in 2010) and Ag in liver and muscle (higher in 2011). No significant differences were detected in total concentrations of organochlorine compounds in Balearic shearwaters between years, although PCB congeners -101 and -180 presented higher concentrations in individuals from 2010. The PCB congeners -138, -153 and -180, and 4.4-DDE were detected in all individuals. This study on toxic elements and organic pollutants in wintering Balearic shearwaters provides baseline data from which deviations can be detected in the future.

Small-scale environmental characteristics associated with nesting burrows of the Newell's Shearwater (Puffinus newelli) and Hawaiian Petrel (Pterodroma sandwichensis) were documented in mesic and wet montane forest on the island of Kauai, Hawaii, USA. Most plots containing burrows were located on steep slopes, ranging from 28° to 48° (median = 39°) for the Newell's Shearwater and 0° to 67° (median = 34.5°) for the Hawaiian Petrel. Plots generally contained > 20% to 40% up to > 80% to 100% estimated vegetation cover 0–1 m above ground and > 0% to 20% up to > 60% to 80% cover 1–2 m above ground. Plots were also associated with estimated canopy cover from > 0% to 10% up to > 80% to 90% for the Newell's Shearwater and 0% up to > 70% to 80% for the Hawaiian Petrel. Soil in Newell's Shearwater plots tended to be harder 7.62–22.86 cm below ground, which might provide increased burrow stability. Additionally, maximum vegetation height tended to be greater above Newell's Shearwater plots (median = 6.00 m...

Sea ice now forms later and melts earlier than it did 4 decades years ago, and it now melts completely in all parts of the Chukchi Sea. This decline in sea ice is expected to have repercussions on the trophic structure in this environment, and there are indications that changes already have taken place in the seabird community. We compared boat-based densities of seabirds in the eastern Chukchi Sea between July and October during 1975–1981 (historical data) with densities during 2007–2012 (recent data). We related the composition of the seabird community to sea-ice cover to explore how the community may be responding to changes in oceanography. The seabird community historically was composed predominantly of piscivorous Black-legged Kittiwakes (Rissa tridactyla) and murres (Uria spp.). In contrast, the seabird community now is composed predominantly of planktivorous seabirds such as Crested Auklets (Aethia cristatella) and Short-tailed Shearwaters (Puffinus tenuirostris). Total abundance of seabirds declined in three of four strata in the eastern Chukchi Sea, largely due to declines in densities of piscivorous and omnivorous species. These changes in the abundance and community composition of seabirds were associated with changes in ice cover. Earlier ice retreat appears to contribute to an environment that is more favorable to the sustained production of large oceanic copepods and euphausiids. We propose that long-term changes (4 decades) in the abundance and composition of the seabird community reflect an increase in the availability of large zooplankton prey in the region.

The effects of the fishing industry on the marine environment have been studied and described over the past two decades. Trawl-netting is a common but non-selective method of fishing that often captures non-target specimens of no commercial value that are discarded at sea. We discovered an unreported threat caused by fisheries discards on seabirds attending fishing activities in Brazilian waters: choking by feeding on discarded Atlantic Midshipman (Porichthys porosissimus). Over 6 years of monitoring (2007–13), we recorded five procellariiform species – Atlantic Yellow-nosed Albatross (Thalassarche chlororhynchos), Cory’s Shearwater (Calonectris diomedea), Sooty Shearwater (Ardenna grisea), Great Shearwater (Ardenna gravis) and Manx Shearwater (Puffinus puffinus) – dead on beaches with Atlantic Midshipman stuck in their throats and showing evidence of death by suffocation as a result of blockage of the airways through choking. This phenomenon has not been consistently described, and the consequences of the consumption of fishery discards by seabirds in Brazilian waters remain poorly understood.

Understanding links between habitat characteristics and foraging efficiency helps predict how environmental changes influence populations of top predators. This study examines whether measurements of prey (clupeids) availability varied over stratification gradients, and determined if any of those measurements coincided with aggregations of foraging seabirds (common guillemot Uria aalge and Manx shearwater Puffinus puffinus ) in the Celtic Sea, UK. The probability of encountering foraging seabirds was highest around fronts between mixed and stratified water. Prey were denser and shallower in mixed water, whilst encounters with prey were most frequent in stratified water. Therefore, no single measurement of increased prey availability coincided with the location of fronts. However, when considered in combination, overall prey availability was highest in these areas. These results show that top predators may select foraging habitats by trading-off several measurements of prey availability. By showing that top predators select areas where prey switch between behaviours, these results also identify a mechanism that could explain the wider importance of edge habitats for these taxa. As offshore developments (e.g. marine renewable energy installations) change patterns of stratification, their construction may have consequences on the foraging efficiency of seabirds.

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...

Changes in oceanographic conditions, shaped by changes in large-scale atmospheric phenomena such as the North Atlantic Oscillation (NAO), alters the structure and functioning of marine ecosystems. Such signals are readily captured by marine top predators, given that their use of foraging habitats and diets change when the NAO changes. In this study we assessed sexual, seasonal and annual (2010/11–2012/13) differences in diet, trophic and isotopic niche (using δ15N and δ13C values of whole blood, 1st primary, 8th secondary and breast feathers), foraging locations and oceanographic variation within foraging areas for Macaronesian shearwaters' (Puffinus baroli) during two years of contrasting NAO values, and between two sub-tropical islands 330 km apart in the North Atlantic Ocean, Cima Islet and Selvagem Grande. These two locations provide contrasting oceanographic foraging regimes for the birds, because the second colony is much closer to the African coast (375 vs 650 km), and, therefore, to the upwelling area of the Canary Current. There was a marked environmental perturbation in 2010/2011, related with a negative NAO Index and lower marine productivity (lower concentration of Chlorophyll a). This event corresponded to the Macaronesian shearwaters feeding farther north and west, which was readily seen in change of both δ15N and δ13C values, and in a higher intake of cephalopods. Diet and stable isotopes did not differ between sexes. Regurgitation analysis indicate a dominance of cephalopods in both islands, but prey fish were important for Selvagem Grande in 2012 and cephalopods for Cima Islet in 2011. Both δ15N and δ13C values were significantly higher for Cima Islet than for Selvagem Grande, irrespective of year, season and tissue sampled. SIBER analysis showed smaller isotopic niches for the breeding period. Our study suggests that during years of poor environmental conditions Macaronesian shearwaters shift their foraging location to more pelagic waters, take more cephalopods and overall present a narrower isotopic niche.

The island of Kaua‘i, Hawai‘i has several remaining populations of endangered, endemic Hawaiian petrels (Pterodroma sandwichensis) and Newell's shearwaters (Puffinus newelli) that would be threatened by the presence of predatory mongooses (Herpestes javanicus). Despite over 200 putative sightings, 1 road-kill and 2 recent captures, it is not clear if mongooses have actually become established on Kaua‘i. Comparing road transects on three Hawaiian islands, we found mongooses present on O‘ahu and Maui where they are known to occur and no evidence of significant populations on Kaua‘i. Three population scenarios are presented that would account for the three specimens, the past sightings, and the absence of sightings on our transects on Kaua‘i.

Identifying the overlap of commercial fishing grounds and seabird habitat can suggest areas of high bycatch risk and inform management and mitigation measures. We used Bayesian state space modeling to describe the movements of 10 satellite-tagged Great Shearwaters and a bivariate kernel density technique to investigate spatial overlap with commercial fishing effort to predict areas of high bycatch in the Gulf of Maine. We then used contemporaneous fishery observer data to test the validity of our predictions, highlighting an area constituting 1% of the Gulf of Maine as having the highest bycatch risk that accounted for 50% of observed takes. Fishery observer data also provided insights into characteristics of the seabird-fishery interactions. Our results indicate that a relatively small number of satellite-tagged seabirds, when combined with fishery-dependent data, can lead to identifying high-bycatch areas, particular fishing practices that might increase risk, and fishing communities that could be targeted for education/mitigation.

Since 2004 there has been mounting evidence of the severe impact of introduced house mice (Mus musculusL.) killing chicks of burrow-nesting petrels at Gough Island. We monitored seven species of burrow-nesting petrels in 2014 using a combination of infra-red video cameras augmented by burrowscope nest inspections. All seven camera-monitored Atlantic petrel (Pterodroma incertaSchlegel) chicks were killed by mice within hours of hatching (average 7.2±4.0 hours) with an 87% chick failure rate (n=83 hatchlings). Several grey petrel (Procellaria cinereaGmelin) chicks were found with mouse wounds and 60% of chicks failed (n=35 hatchlings). Video surveillance revealed one (of seven nests filmed) fatal attack on a great shearwater (Puffinus gravisO’Reilly) chick and two (of nine) on soft-plumaged petrel (Pterodroma mollisGould) chicks. Mice killed the chicks of the recently discovered summer-breeding MacGillivray’s prion (Pachyptila macgillivrayiMathews), with a chick mortality rate of 82% in 2013/14 and 100% in 2014/15. The closely-related broad-billed prion (P. vittataForster) breeds in late winter and also had a chick mortality rate of 100% in 2014. The results provide further evidence of the dire situation for seabirds nesting on Gough Island and the urgent need for mouse eradication.

Seabird bycatch in commercial fisheries has been a growing conservation concern over the past 25 years. Large-scale fisheries employing gears known to incidentally catch seabirds operate off eastern Canada, however, regional bycatch information is limited. Using data collected from 1998–2011 by observers onboard Canadian domestic and foreign vessels, fishery sectors and target fisheries taking seabirds were identified, as were the seabirds most frequently taken. In addition, maps of seabird bycatch rates were used to identify localized areas where catch rates were high. Seabird bycatch was widespread. Despite generally low observer coverage, > 5000 bird deaths were recorded; most observed mortalities occurred in gillnet and longline sectors during summer and autumn. While the overall magnitude of seabird bycatch has likely decreased substantially since closure of the Atlantic cod Gadus morhua and Atlantic salmon Salmo salar gillnet fisheries in 1992, localized areas with high bycatch rates persist. For example, in Baffin Bay and Davis Strait, bycatch rates of northern fulmars Fulmarus glacialis were high in gillnet and longline fisheries targeting Greenland halibut Reinhardtius hippoglossoides near breeding colonies. In offshore areas of the Grand Bank, catch rates of migrant shearwaters (Puffinus and Calonectris spp.) were high in deep-set gillnet fisheries for Greenland halibut and monkfish Lophius americanus during summer. In inshore regions of eastern Newfoundland, gillnets set for Atlantic cod near breeding colonies resulted in high bycatch rates of murres Uria spp. and shearwaters during summer. High bycatch rates were also observed in pelagic longline fisheries along the Scotian Shelf. While the observer data have highlighted several localized areas with high bycatch rates, information for inshore gillnet fisheries, which take seabirds but are poorly covered by the observer programme, and regional information on fishing effort must both be considered for comprehensive assessment of seabird risk areas and consequent management needs in eastern Canada. Copyright © 2015 John Wiley & Sons, Ltd.

Townsend’s Shearwater (Puffinus auricularis auricularis) is a highly threatened bird and currently breeds on Socorro and Clarion Islands, Mexico. This subspecies has minor differences in plumage patterns when compared to Newell’s Shearwater of Hawaii (USA) (Puffinus auricularis newelli). These two forms are recognized as subspecies by the American Ornithologist’s Union. However, some authors consider them as distinct species based on subtle plumage differences and different breeding chronologies. We used Bayesian and Maximum Likelihood methods to compare the cytochrome b and cytochrome oxidase I sequences from Townsend’s Shearwaters with archived mitochondrial sequences from other taxa in the genus Puffinus. Townsend’s and Newell’s Shearwaters show little genetic differentiation; hence, there is no justification to consider them as different species. Additionally, differences in morphology and ecology might be the result of founder effects and phenotypic plasticity; proven migratory potential provides support to the current taxonomic assessment that considers these birds as conspecifics. We recommend the continued treatment of Townsend’s and Newell’s Shearwaters as two subspecies of P. auricularis. We also advocate treating the Rapa Shearwater (P. myrtae) as a distinct species.

Within breath-hold diving endotherms, procellariiform seabirds present an intriguing anomaly as they regularly dive to depths not predicted by allometric models. How this is achieved is not known as even basic measures of physiological diving capacity have not been undertaken in this group. To remedy this we combined time depth recorder (TDR) measurements of dive behaviour with haematology and oxygen store estimates for 3 procellariiform species (common diving petrels Pelecanoides urinatrix urinatrix; grey-faced petrels Pterodroma macro ptera gouldi; and sooty shearwaters Puffinus griseus) during their incubation phase. Among species, we found distinct differences in dive depth (average and maximal), dive duration and dives h �1 , with sooty shearwaters diving deeper and for longer than grey-faced petrels and common diving petrels. Conversely, common diving petrels dove much more frequently, albeit to shallow depths, whereas grey-faced petrels rarely dived whatsoever. Such differences in dive behaviour were reflected in haematological parameters, with sooty shearwaters having higher red blood cell counts and haematocrit (Hct) values compared to common diving and grey-faced petrels; whereas common diving petrels had significantly lower Hct but possessed higher haemoglobin concentrations per cell and greater respiratory oxygen stores than both sooty shearwaters and grey-faced petrels. Such results provide the first insights into the physiological traits underpinning procellariiform dive behaviour, and confirm the trend for deep-diving seabirds to have proportionally lower blood and respiratory oxygen stores than shallow divers.

In recent years, there have been increasing reports of ingestion of marine plastic debris in seabirds. Our aim was to assess the frequency and effects of ingested plastic debris in pre-fledging Short-tailed Shearwaters (Puffinus tenuirostris) in Tasmania. We conducted necropsies of 171 Shearwater chicks, confiscated after illegal poaching, to determine the presence of plastic debris in the proventriculus and ventriculus. We also examined whether there was a correlation between body condition (based on body mass and fat-scores) and quantity of plastic ingested (by count and weight). We recorded 1032 ingested plastic particles, consisting of industrial plastic (31%) and user plastic (69%). Most of the Shearwater chicks (96%) contained plastic debris with a mean of 148.1 mg per bird (s.e. 8.1). Most plastic was found in the ventriculus. Light-coloured plastic dominated (63.8%), with the rest medium (22.1%) and dark (14.1%) plastics. We found that total mass of ingested plastic was not significantly related to body condition, or fat-scores or mass individually. Our study highlights the prevalence of plastic pollution in apparently healthy Shearwater chicks and underscores concern regarding the effects of increasing marine pollution on a global scale.

Following breeding, sooty shearwaters Puffinus griseus leave New Zealand waters and migrate to 1 of 3 distinct areas in the North Pacific Ocean, effectively exploiting environmen- tal resources across a large proportion of this northern ocean basin. In this study, we combined electronic tracking technology with stable isotope analyses (δ 15 N and δ 13 C) of feathers grown dur- ing the non-breeding period in order to evaluate whether isotope signatures can be used to iden- tify specific non-breeding areas used by sooty shearwaters. A region to the east of Japan was utilised by the majority of tracked birds, whereas others used areas off the west coast of North America. Stable isotope values of feathers allowed the discrimination of individuals that used each of the 3 different non-breeding areas, and suggested that birds off Japan can be further separated into 'coastal' and 'offshore' groups. Our results confirm the utility of using stable isotope analysis, validated by tracking devices, as a tool to determine distribution and habitat use of a long-range oceanic migrant, the sooty shearwater. These results also highlight the resource connectivity between the northern and southern Pacific Ocean basin.

In long-lived species, care-giving parents are expected to balance their own condition with that of their offspring. Many species of seabirds display a unique behavioural adaptation for managing these conflicting demands known as dual foraging, in which long trips, largely for self-maintenance, are alternated with short trips, which are primarily for offspring care. While dual foraging is a widely studied behaviour, it entails a complication that is seldom discussed: if parents independently employ a dual-foraging strategy, chicks might be abandoned for extended periods when the long trips of both partners coincide. Whether partners coordinate their dual-foraging strategies, however, is largely unknown. To investigate this possibility, we used radiofrequency identification readers coupled with passive integrated transponder tags to record extended sequences of foraging trips for breeding Manx shearwaters, Puffinus puffinus. Our results show a pattern of foraging trips that indicates a high level of coordination between parents, which facilitates consistent provisioning. Additionally, we show that the propensity for pairs to coordinate declines across the chick-rearing period. Given the potential costs of not coordinating, we expect this behaviour to be widely spread among dual-foraging species.

Indices calculated from “muttonbirding” diaries collected by the Rakiura Māori of New Zealand were correlated with future values of the Southern Oscillation Index (SOI), and the Pacific Decadal Oscillation (PDO) from 1957 to 2010. Spearman correlations showed that La Nina events tended to occur after those harvest seasons with relatively high success and chick size, whereas El Nino events tended to occur after harvest seasons with relatively low success and chick size. Generalized boosted regression models show that chick size alone is able to predict shifts in SOI from 0 to 12 months after the harvest. A model that included chick size, 2-year average PDO (prior to the harvest), and one year averages of SOI (prior to the harvest), was able to predict shifts in SOI 13–20 months after the harvest. It is likely that sooty shearwater adults (and therefore chick size and quantity) are being affected by oceanographic conditions that are also precursors to shifts in SOI, and that there is a complex interaction between PDO prior to the harvest, the harvest indices and SOI. The location and timing of adult birds at the time they are provisioning chicks could lead to potential mechanisms and requires further study.

Seabirds are marine top predators and accumulate high levels of metals and metalloids in their tissues. Contamination by metals in the highly productive offshore region has become a matter of public concern. It is home to 80% of the seabird population in the U.S.A., 95% of northern fur seals (Callorhinus ursinus), and major populations of Steller sea lions (Eumetopias jubatus), walruses (Odobenus rosmarus) and whales. Here, the concentrations of eight heavy metals (Hg, Cd, Cr, Co, Ni, Cu, Zn and Pb) and a metalloid (As) in the liver and kidneys of the northern fulmar (Fulmarus glacialis), thick-billed murre (Uria lomvia), short-tailed shearwater (Puffinus tenuirostris), tufted puffin (Fratercula cirrhata) and horned puffin (Fratercula corniculata) collected in the Bering Sea were measured. As proxies of trophic level and habitat, nitrogen (delta N-15) and carbon (delta C-13) stable isotope ratios of breast muscles were also measured. Hepatic Hg concentration was high in northern fulmar, whereas Cd level was high in tufted puffin and northern fulmar. The Hg concentration and d15N value were positively correlated across individual birds, suggesting that Hg uptake was linked to the trophic status of consumed prey. Furthermore, Hg concentration in our study was higher than those of the same species of seabirds collected in 1990.

International audience; Marine protected areas (MPAs) are considered one of the main tools in both fisheries and conservation management to protect threatened species and their habitats around the globe. However, MPAs are underrepresented in marine environments compared to terrestrial environments. Within this context, we studied the Atlantic non-breeding distribution of the southern population of Balearic shearwaters (Puffinus mauretanicus) breeding in Ibiza during the 2011-2012 period based on global location sensing (GLS) devices. Our objectives were (1) to identify overall Important Atlantic Areas (IAAs) from a southern population, (2) to describe spatio-temporal patterns of oceanographic habitat use, and (3) to assess whether existing conservation areas (Natura 2000 sites and marine Important Bird Areas (IBAs)) cover the main IAAs of Balearic shearwaters. Our results highlighted that the Atlantic staging (from June to October in 2011) dynamic of the southern population was driven by individual segregation at both spatial and temporal scales. Individuals ranged in the North-East Atlantic over four main IAAs (Bay of Biscay: BoB, Western Iberian shelf: WIS, Gulf of Cadiz: GoC, West of Morocco: WoM). While most individuals spent more time on the WIS or in the GoC, a small number of birds visited IAAs at the extremes of their Atlantic distribution range (i.e., BoB and WoM). The chronology of the arrivals to the IAAs showed a latitudinal gradient with northern areas reached earlier during the Atlantic staging. The IAAs coincided with the most productive areas (higher chlorophyll a values) in the NE Atlantic between July and October. The spatial overlap between IAAs and conservation areas was higher for Natura 2000 sites than marine IBAs (areas with and without legal protection, respectively). Concerning the use of these areas, a slightly higher proportion of estimated positions fell within marine IBAs compared to designated Natura 2000 sites, with Spanish and Portuguese conservation areas being the most visited. Our results support the current design of conservation areas in Spain and Portugal regarding the protection of adult breeders of this highly mobile species.

SummaryThe Balearic Shearwater Puffinus mauretanicus is considered one of the most threatened seabirds in the world, with the breeding population thought to be in the range of 2,000–3,200 breeding pairs, from which global population has been inferred as 10,000 to 15,000 birds. To test whether the actual population of Balearic Shearwaters is larger than presently thought, we analysed the data from four land-based census campaigns of Balearic Shearwater post-breeding migration through the Strait of Gibraltar (mid-May to mid-July 2007–2010). The raw results of the counts, covering from 37% to 67% of the daylight time throughout the migratory period, all revealed figures in excess of 12,000 birds, and went up to almost 18,000 in two years. Generalised Additive Models were used to estimate the numbers of birds passing during the time periods in which counts were not undertaken (count gaps), and their associated error. The addition of both counted and estimated birds reveals figures of between 23,780 and 26,535 Balearic Shearwaters migrating along the north coast of the Strait of Gibraltar in each of the four years of our study. The effects of several sources of bias suggest a slight potential underestimation in our results. These figures reveal the urgent need to reformulate the population viability analysis for the species, and then if necessary reconsider its conservation status.

Rakiura Māori (New Zealand's southernmost group of indigenous peoples) have harvested the chicks of burrow-nesting Sooty Shearwaters (Tītī; Puffinus griseus) for generations. As part of the harvest process, some families have maintained annual harvest diaries, some dating back to the 1950s. We used generalized boosted regression models, a machine-learning algorithm, to calculate a harvest index that takes into account factors that could impact the numbers of birds taken on any given hunt. For predicted vs. observed values, r2 was between 0.59 and 0.90 for the nanao (first half of the season, when chicks are harvested from burrows during the day) and 0.67 and 0.88 for the rama (second half of the season, during which chicks are harvested from the surface at night). Exploration of the controlling factors of the models revealed that “day of season” plays an important role in predicting daily harvest during the second half of the season (the rama). The nightly tally in the rama peaked approximately halfway through (10–15 days in), which is probably related to the timing of birds emerging from burrows to fledge. The models also suggested that data from the rama (when chicks are 100–120 days old) may be the most suitable for long-term monitoring of populations of Sooty Shearwaters due to consistencies in calculated harvest indices between diaries. Nanao harvest indices, although less consistent, showed patterns similar to those of the rama. When comparing these data to the harvest indices calculated by general linear models by Clucas and colleagues, we found that the agreement between both indices was r2 = 0.31 and r2 = 0.59 for the nanao and rama, respectively. The use of machine learning to correct for extraneous factors (e.g., hunting effort, skill level, or weather) and to create standardized measures could be applied to other systems such as fisheries or terrestrial resource management.

The marine ecosystems of the Bering Sea and adjacent southern Chukchi Sea are experiencing rapid changes due to recent reductions in sea ice. Short-tailed shearwaters Puffinus tenuirostris visit this region in huge numbers between the boreal summer and autumn during non-breeding season, and represent one of the dominant top predators. To understand the implications for this species of ongoing environmental change in the Pacific sub-Arctic and Arctic seas, we tracked the migratory movements of 19 and 24 birds in 2010 and 2011, respectively, using light-level geolocators. In both years, tracked birds occupied the western (Okhotsk Sea and Kuril Islands) and eastern (southeast Bering Sea) North Pacific from May to July. In August–September of 2010, but not 2011, a substantial proportion (68 % of the tracked individuals in 2010 compared to 38 % in 2011) moved through the Bering Strait to feed in the Chukchi Sea. Based on the correlation with oceanographic variables, the probability of shearwater occurrence was highest in waters with sea surface temperatures (SSTs) of 8–10 °C over shallow depths. Furthermore, shearwaters spent more time flying when SST was warmer than 9 °C, suggesting increased search effort for prey. We hypothesized that the northward shift in the distribution of shearwaters may have been related to temperature-driven changes in the abundance of their dominant prey, krill (Euphausiacea), as the timing of krill spawning coincides with the seasonal increase in water temperature. Our results indicate a flexible response of foraging birds to ongoing changes in the sub-Arctic and Arctic ecosystems.

In this study, we report the (210)Po and (210)Pb concentrations of bone, muscle and liver samples that were obtained from twelve different marine bird species stranded on beaches in the central-north region of Rio de Janeiro State. Both radionuclides were highly concentrated in the liver samples; however, the lowest mean (210)Po/(210)Pb activity ratio (1.3) was observed in bones compared with liver and muscle (16.8 and 13.8, respectively). Among the species that were studied, Fregata magnificens, with a diet based exclusively on fish, had the lowest (210)Pb and (210)Po concentrations and the lowest (210)Po/(210)Pb activity ratio. The (210)Po concentrations in Puffinus spp. liver samples followed a log-normal distribution, with a geometric mean of 300 Bq kg(-1)wet weight. Only two references pertaining to (210)Po in marine birds were found in a Web of Science search of the literature, and each study reported a different concentration value. The values determined in this experiment are consistent with those in one of the previous studies, which also included one of the species studied in this work. No values for (210)Pb in marine birds have been published previously.