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Seabirds are one of the most threatened avian groups. Viruses, including herpesvirus, represent considerable threats to marine avifauna. Herein, our goal was to survey herpesvirus in Procellariiformes that stranded in Brazil between June and July 2021. We analyzed 12 Cory's shearwaters (Calonectris borealis), two Great Shearwaters (Ardenna gravis, syn. Puffinus gravis) and one Yellow-nosed Albatross (Thalassarche chlororynchos) found in an unusual mortality event in Bahía state, northeastern Brazil. After necropsy, selected tissue samples were tested for herpesvirus using a broad-range nested PCR. Overall, 20% (3/15) of the birds were herpesvirus-positive, i.e., two Cory's Shearwaters and one Great Shearwater. One alphaherpesvirus sequence type was identified in each shearwater species, classified into the genus Mardivirus. This study describes two likely novel herpesviruses in shearwaters, contributing to the currently very scarce data regarding infectious agents in Procellariiformes. Further studies are necessary to evaluate the presence and characteristics of herpesvirus in Procellariiformes, and the presence (or not) of related disease in order to understand the epidemiology of this infectious agent and eventually contribute to the conservation of this endangered seabird group. [ABSTRACT FROM AUTHOR]

The yelkouan shearwater Puffinus yelkouan is endemic to the Mediterranean and Black Seas, and classified as Vulnerable in the IUCN Red List. Information on the species’ distribution and habitat use in the eastern Mediterranean is scant, and only a few studies were based on direct visual observations in offshore waters. Here, we provide information on 1) the occurrence of yelkouan shearwaters within a 3000 km² study area off the region of Veneto, Italy, in the northwestern Adriatic Sea, based on visual surveys conducted from small boats between April and October 2018-2022 (effort: 169 days, 23,836 km), and 2) the geographic, bathymetric and oceanographic variables likely to drive the species’ offshore distribution. Yelkouan shearwaters (238 sightings, 916 individuals) were observed in waters 9-33 m deep, between 2 and 24 km from the coast. Individual counts ranged between 1 and 100, with 95% of the encounters having less than 10 individuals. An Explainable Boosting Machine model-a machine learning technique based on generalized additive models-selected chlorophyll a as the most important variable to explain the species’ occurrence, followed by distance from the coast, and bottom depth. The model indicated a higher occurrence in waters with chlorophyll a less than ~2.3 mg/m³, farther than ~15 km from the coast, and deeper than ~22 m. The effects of SST, salinity, and day of the year were less clear. This study provides insight into the offshore distribution of yelkouan shearwaters, within one of the Mediterranean areas most exposed to cumulative human threats. [ABSTRACT FROM AUTHOR]

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As top predators, seabirds can be indirectly impacted by climate variability and commercial fishing activities through changes in marine communities. However, high mobility and foraging behavior enable seabirds to exploit prey distributed patchily in time and space. Despite this environmental adaptability, seabirds are the world’s most threatened birds and there is, therefore, an urge to acquire information about their ecological and foraging requirements through the study of their diet. Traditionally, the diet of seabirds is assessed through the morphological identification of prey remains in regurgitates. This sampling method is invasive for the bird and limited in terms of taxonomic resolution. However, the recent progress in DNA-based approaches is now providing a noninvasive means to more comprehensively and accurately characterize animal diets. We used a noninvasive metabarcoding approach to characterize the diet of the Westland Petrel (Procellaria westlandica), which is an endangered burrowing species, endemic to the South Island of New Zealand. We collected 99 fresh fecal samples in 2 different seasons and in 2 different subcolonies. Our aim was to describe the Westland Petrel’s diet and to investigate seasonal and spatial variations to their diet to understand the feeding requirements of this species. We also specifically investigated potential links with the New Zealand fishery industry to inform efficient conservation practices. Our noninvasive dietary DNA (dDNA) approach also highlighted significant differences in diet between seasons (incubation vs. chick-rearing season) and between sampling sites (two subcolonies 1.5 km apart). This suggests plasticity in the foraging strategy of the Westland Petrel. We found that amphipods were the most common prey, followed by cephalopods, and fish. Our findings could be the result of natural foraging behavior but also suggest a close link between the composition of prey items and New Zealand’s commercial fishing activities. In particular, the high abundance of amphipods could be the result of Westland Petrels feeding on discarded fisheries waste (fish guts). This close relationship to New Zealand’s fisheries may put stress on the resilience of the Westland Petrel. This valuable knowledge about Westland Petrel foraging needs is key to design efficient conservation plans for this iconic species. We illustrate how dDNA can inform the conservation of endangered or at-risk species that have elusive foraging behaviors.

Coastal seabirds serve as sentinels of ecosystem health due to their vulnerability to contamination from human activities. However, our understanding on how contaminant burdens affect the physiological and health condition of seabirds is still scarce, raising the uncertainty on the species' vulnerability vs tolerance to environmental contamination. Here, we quantified 15 Trace Elements (TE) in the blood of gull (yellow-legged gull Larus michahellis and Audouin's gull Ichthyaetus audouinii) and shearwater (Cory's shearwater Calonectris borealis) adults, breeding in five colonies along the Portuguese coastline. Additionally, stable isotopes of carbon (δ 13C) and nitrogen (δ 15N) were quantified to elucidate foraging habitat and trophic ecology of adults, to identify potential patterns of TE contamination among colonies. We used immuno-haematological parameters as response variables to assess the influence of TE concentrations, stable isotope values, and breeding colony on adults' physiological and health condition. Remarkably, we found blood mercury (Hg) and lead (Pb) concentrations to exceed reported toxicity thresholds in 25% and 13% of individuals, respectively, raising ecotoxicological concerns for these populations. The breeding colony was the primary factor explaining variation in five out of six models, underlining the influence of inherent species needs on immuno-haematological parameters. Model selection indicated a negative relationship between erythrocyte sedimentation rate and both Hg and selenium (Se) concentrations, but a positive relationship with δ 13C. The number of immature erythrocyte counts was positively related to Hg and Se, particularly in yellow-legged gulls from one colony, highlighting the colony-site context's influence on haematological parameters. Further research is needed to determine whether essential TE concentrations, particularly copper (Cu) and Se, are falling outside the normal range for seabirds or meet species-specific requirements. Continuous monitoring of non-essential TE concentrations like aluminium (Al), Hg, and Pb, is crucial due to their potential hazardous concentrations, as observed in our study colonies. [Display omitted] • Some individuals exceeded toxicity thresholds for blood Hg and Pb concentrations. • Se:Hg molar ratios suggest that these species might be protected from Hg toxicity. • Colony emerged as a primary factor of variation in seabird health parameters. • ESR and IE counts related to δ 13C values, and Hg and Se concentrations. • Further research to assess if essential TE levels meet species-specific needs. [ABSTRACT FROM AUTHOR]

Interspecific introgression can occur between species that evolve rapidly within an adaptive radiation. Pachyptila petrels differ in bill size and are characterised by incomplete reproductive isolation, leading to interspecific gene flow. Salvin's prion (Pachyptila salvini), whose bill width is intermediate between broad-billed (P. vittata) and Antarctic (P. desolata) prions, evolved through homoploid hybrid speciation. MacGillivray's prion (P. macgillivrayi), known from a single population on St Paul (Indian Ocean), has a bill width intermediate between salvini and vittata and could also be the product of interspecies introgression or hybrid speciation. Recently, another prion population phenotypically similar to macgillivrayi was discovered on Gough (Atlantic Ocean), where it breeds 3 months later than vittata. The similarity in bill width between the medium-billed birds on Gough and macgillivrayi suggest that they could be closely related. In this study, we used genetic and morphological data to infer the phylogenetic position and evolutionary history of P. macgillivrayi and the Gough medium-billed prion relative other Pachyptila taxa, to determine whether species with medium bill widths evolved through common ancestry or convergence. We found that Gough medium-billed prions belong to the same evolutionary lineage as macgillivrayi, representing a new population of MacGillivray's prion that originated through a colonisation event from St Paul. We show that macgillivrayi's medium bill width evolved through divergence (genetic drift) and independently from that of salvini, which evolved through hybridisation (gene flow). This represents the independent convergence towards a similarly medium-billed phenotype. The newly discovered MacGillivray's prion population on Gough is of utmost conservation relevance, as the relict macgillivrayi population in the Indian Ocean is very small. [ABSTRACT FROM AUTHOR]

Abstract Population estimates are commonly generated and used in conservation science. All estimates carry inherent uncertainty, but little attention has been given to when and how this uncertainty limits their use. This requires an understanding of the specific purposes for which population estimates are intended, an assessment of the level of uncertainty each purpose can tolerate, and information on current uncertainty. We conducted a review and meta‐analysis for a widespread group of seabirds, the petrels, to better understand how and why population estimates are being used. Globally petrels are highly threatened, and aspects of their ecology make them difficult to survey, introducing high levels of uncertainty into population estimates. We found that by far the most common intended use of population estimates was to inform status and trend assessments, while less common uses were trialling methods to improve estimates and assessing threat impacts and conservation outcomes. The mean coefficient of variation for published estimates was 0.17 (SD = 0.14), with no evidence that uncertainty has been reduced through time. As a consequence of this high uncertainty, when we simulated declines equivalent to thresholds commonly used to trigger management, only 5% of studies could detect significant differences between population estimates collected 10 years apart for populations declining at a rate of 30% over three generations. Reporting of uncertainty was variable with no dispersion statistics reported with 38% of population estimates and most not reporting key underlying parameters: nest numbers/density and nest occupancy. We also found no correlation between uncertainty in petrel population estimates and either island size, body size or species threat status – potential predictors of uncertainty. Key recommendations for managers are to be mindful of uncertainty in past population estimates if aiming to collect contemporary estimates for comparison, to report uncertainty clearly for new estimates, and to give careful consideration to whether a proposed estimate is likely to achieve the requisite level of certainty for the investment in its generation to be warranted. We recommend a practitioner‐based value of information assessment to confirm where there is value in reducing uncertainty.

Species inventories and biodiversity assessments are critical to conservation. Yet cryptic species or recolonizing species can be challenging to detect. DNA metabarcoding provides an alternative tool to identify species that can be difficult to observe during field surveys. We test the efficacy of DNA analysis to identify burrowing petrel species in a rapidly changing landscape, on a remote sub‐Antarctic island following pest eradication. Discarded feathers and scats provided high quality DNA for species identification, assisting in detection of new species arrivals and new breeding sites across Macquarie Island. We highlight how DNA metabarcoding informs species inventories and is a valuable tool to complement seabird field surveys. [ABSTRACT FROM AUTHOR]

We describe a new Procellaria petrel species from the late Pliocene of Taranaki, New Zealand. The new species is most similar morphologically to the White-Chinned Petrel (P. aequinoctialis), Spectacled Petrel (P. conspicillata) and the Westland Petrel (P. westlandica). Compared with those taxa, the new species has a deeper and shorter premaxilla, longer coracoid and shorter wings, while its legs are a similar size. Today, New Zealand is the centre of global diversity of the genus, with four breeding species. This is the first fossil species of Procellaria to be described from New Zealand, attesting to a reasonably long history of this genus in the region. [ABSTRACT FROM AUTHOR]

Abstract Background In seabirds, the extent of population genetic and phylogeographic structure varies extensively among species. Genetic structure is lacking in some species, but present in others despite the absence of obvious physical barriers (landmarks), suggesting that other mechanisms restrict gene flow. It has been proposed that the extent of genetic structure in seabirds is best explained by relative overlap in non-breeding distributions of birds from different populations. We used results from the analysis of microsatellite DNA variation and geolocation (tracking) data to test this hypothesis. We studied three small (130–200 g), very abundant, zooplanktivorous petrels (Procellariiformes, Aves), each sampled at two breeding populations that were widely separated (Atlantic and Indian Ocean sectors of the Southern Ocean) but differed in the degree of overlap in non-breeding distributions; the wintering areas of the two Antarctic prion (Pachyptila desolata) populations are separated by over 5000 km, whereas those of the blue petrels (Halobaena caerulea) and thin-billed prions (P. belcheri) show considerable overlap. Therefore, we expected the breeding populations of blue petrels and thin-billed prions to show high connectivity despite their geographical distance, and those of Antarctic prions to be genetically differentiated. Results Microsatellite (at 18 loci) and cytochrome b sequence data suggested a lack of genetic structure in all three species. We thus found no relationship between genetic and spatial structure (relative overlap in non-breeding distributions) in these pelagic seabirds. Conclusions In line with other Southern Ocean taxa, geographic distance did not lead to genetic differences between widely spaced populations of Southern Ocean petrel species.

In several species, the rusty color of hair or feathers is due to pheomelanin pigments, whose adaptive function is unknown. Pheomelanin may be costly because it is phototoxic and its production consumes a key intracellular antioxidant. Pheomelanin-based traits are, however, positively associated with individual quality in several bird species, where they have thus been suggested to have evolved through sexual selection. Here we investigated the signaling potential of the pheomelanin-based coloration of the crown feathers in the blue petrel. Although this pelagic seabird is nocturnal at the breeding colony and breeds within deep burrows, it might use visual communication when settled on the water during daytime. We tested the correlation between crown color and several fitness-related traits, and we found that higher-quality females displayed less-orange crown than poorer-quality females. This result is inconsistent with an adaptive function of pheomelanin-based coloration in inter-, or intra-, sexual selection in females. We suggest that it might, however, be in line with a signaling function of eumelanin-based coloration, if inter-individual variations in orange coloration are mainly due to eumelanin-to-pheomelanin ratio, rather than to pheomelanin quantity. In contrast to females, we did not find strong evidence for associations between melanin-based coloration and individual quality in males, suggesting sex-specific selective pressures on melanin-based traits in this species. [ABSTRACT FROM AUTHOR]

Skuas are top predator and scavenger seabirds in marine and terrestrial ecosystems and monitoring their diet can provide valuable insights on the abundance and distribution of prey. The diet of the brown skua was studied at Mayes Island, Kerguelen archipelago, by collection of prey remains during their breeding cycle in 2013. We investigated a potential diet shift by comparing our results to those obtained two decades ago at the same colony. Our results confirmed the high specialisation of this skua colony in active predation of two burrowing petrels: the blue petrel and the thin-billed prion. We observed a shift in the diet of the brown skua with the importance of the thin-billed prion dropping significantly by 15%. Concomitantly, we observed a decreasing trend of burrow occupancy of the two main preys, with a more severe decline for the thin-billed prion. We suspected a dietary shift of brown skuas at Mayes Island related to a change in the relative abundance of blue petrels and thin-billed prions. Diet of brown skuas appears to be a valuable indicator of the relative abundance of burrowing petrels when they constitute the main food resource during breeding. [ABSTRACT FROM AUTHOR]

Reproductive synchrony is a widespread phenomenon that is predicted to be adaptive for prey with specialist predators but not for those with generalist ones. I tested this prediction in three polar seabird species characterized by different levels of predator specialization. In the Antarctic petrel, for which the only predator was highly specialized, hatching dates were highly synchronous and chicks that hatched close to the mean hatching date had a higher survival. In black‐legged kittiwakes and Brünnich's guillemots, whose predators were generalists, breeding was less synchronous and there was no fitness advantage in hatching close to the mean. This study emphasizes the potential importance of the relative timing of reproduction for individual fitness and supports the hypothesis that the adaptive value of breeding synchrony depends on the predator functional response. Reproductive synchrony is a widespread phenomenon, and its adaptive significance is predicted to depend on the predator functional response. I tested this prediction in three polar seabird species characterized by different levels of predator specialization. My results emphasize the importance of the relative timing of reproduction for individual fitness and support the hypothesis that the adaptive value of breeding synchrony depends on the predator functional response. [ABSTRACT FROM AUTHOR]

The Southern Giant Petrel Macronectes giganteus is the largest Procellariidae around the world. Beyond the most striking features on the skull, the strong hooked bill with tubular, dorsally-placed, external nostrils, these petrels have been the focus of diverse studies, except osteological ones. Even less is known about the osteology in juveniles and chicks. A comparative description of the skull anatomy of the Southern Giant Petrel M. giganteus, highlighting the differences along each postnatal ontogenetic stage, is given here. As a result, we found that the shape of the skull does not vary among the compared stages and that there is a progression in the fusion of the elements of the skull and mandible. Besides, less obvious results show a little intraspecific variation among specimens of the same ontogenetic stage, involving osteological features such as the quantity and shape of foramina within pneumatic bone surfaces, and the fact that general size is not associated with sexual dimorphism. The beak acquires its characteristic development and sturdiness from early stages. Conversely, the fossae glandulae nasalis is only developed in juveniles and adults, being absent in earlier stages. [ABSTRACT FROM AUTHOR]

Pelagic seabirds that breed colonially are central-place foragers; their spatial distribution is restricted to marine areas around their colonies during the chick-rearing period, when attendance and food provision to their chicks has to be intense. In this study we analyzed the foraging trips of 11 Scopoli's shearwater Calonectris diomedea breeders that were tagged with GPS data loggers during 2014 in oligotrophic waters (Ionian Sea, western Greece), and assessed the range and oceanographic parameters of their foraging habitat. Contrary to previous findings suggesting a varying foraging strategy depending on the breeding stage, the tracked shearwaters made short trips, less than 4 days long, in the vicinity of the colony. By applying the Adaptive Kernel method, their 50% and 95% foraging range was estimated at 6871 km2 and 23 014 km2 respectively. In addition, generalized additive models showed that sea surface temperature (<25.5°C), minimum distance from the colony (<100 km), fishing pressure index from small scale fisheries (medium values) along with a two-dimensional soap film smoother for space (easting, northing) were the most significant factors affecting at-sea distribution of this marine top predator during the early chick-rearing period (i.e. 99.9% of the final model deviance). Our study will contribute to the revision of the boundaries of the local Special Protection Area (SPA) of Strofades. It will also address the implementation of specific conservation measures for the species at regional and national scale, and the development of a management plan for the protection of the study area. [ABSTRACT FROM AUTHOR]

As an individual moves through its life cycle, it passes through a series of states (age classes, size classes, reproductive states, spatial locations, health statuses, etc.) before its eventual death. The occupancy time in a state is the time spent in that state over the individual’s life. Depending on the life cycle description, the occupancy times describe different demographic variables, for example, lifetime breeding success, lifetime habitat utilisation, or healthy longevity. Models based on absorbing Markov chains provide a powerful framework for the analysis of occupancy times. Current theory, however, can completely analyse only the occupancy of single states, although the occupancy time in a set of states is often desired. For example, a range of sizes in a size-classified model, an age class in an age × stage model, and a group of locations in a spatial stage model are all sets of states. We present a new mathematical approach to absorbing Markov chains that extends the analysis of life histories by providing a comprehensive theory for the occupancy of arbitrary sets of states, and for other demographic variables related to these sets (e.g., reaching time, return time). We apply this approach to a matrix population model of the Southern Fulmar ( Fulmarus glacialoides ). The analysis of this model provides interesting insight into the lifetime number of breeding attempts of this species. Our new approach to absorbing Markov chains, and its implementation in matrix oriented software, makes the analysis of occupancy times more accessible to population ecologists, and directly applicable to any matrix population models. [ABSTRACT FROM AUTHOR]

Delta15N values and associated N concentrations may be useful nutrient cycling metrics for assessing restoration progress, and complement biodiversity assessment. We tested this hypothesis at Pūtaringamotu Riccarton Bush (‘Pūtaringamotu’), a low-rainfall urban forest fragment under restoration since 1974. Foliar and soil measurements came from four indigenous forests (Pūtaringamotu; Saltwater, high rainfall, logged until 2002; Ōkārito, high rainfall, never logged; Scotchman’s Creek, high rainfall, burrowing seabirds present). Despite different disturbance histories, Pūtaringamotu, Ōkārito and Saltwater results all fitted globalδ15N regressions between rainfall and foliar N concentration. Enhanced foliar N concentrations accompanying low rainfall at Pūtaringamotu were similar to seabird-affected Scotchman’s Creek. Although Pūtaringamotu foliarδ15N values showed differences between taxa, they were less pronounced than for Ōkārito; Saltwater showed no effect. Further investigation of nutrient cycling restoration metrics at Pūtaringamotu should therefore emphasise progressive development of differences in foliarδ15N between plant taxa, pooled values being insufficiently sensitive. [ABSTRACT FROM AUTHOR]

The late-Holocene bird remains retrieved during archaeological excavations on pelagic island of Palagruža, Croatia, were analysed. The results of the analysis revealed presence of representatives of nine families: Procellariidae, Sulidae, Ardeidae, Accipitridae, Phasianidae, Rallidae, Laridae, Strigidae and Corvidae. Among the bird remains, the most numerous were remains of the Northern Gannet, Morus bassanus, which were widely distributed in the Mediterranean during the late Pleistocene. The finding of the Northern Gannet bones on Palagruža represents the first fossil record of this species in the Adriatic Sea and indicates a possible breeding site on the island. The direct Accelerator Mass Spectrometry (AMS) radiocarbon dating on two gannet bones revealed the age of 2878 ± 34 and 2694 ± 45 yr BP. Gannet bones from Palagruža were some 6000 years younger than other fossil records of that species from the Mediterranean. It is possible that during the gannet’s northward distributional shift, probably caused by centennial climatic variability and human pressure, gannet colony on that remote island in the Adriatic lasted longer than in the rest of the Mediterranean and existed until the late-Holocene. Lower sea-surface temperatures compared with the eastern Mediterranean, higher nutritive productivity and remoteness of Palagruža provided adequate breeding opportunities during that period. [ABSTRACT FROM AUTHOR]

Background: In seabirds, the extent of population genetic and phylogeographic structure varies extensively among species. Genetic structure is lacking in some species, but present in others despite the absence of obvious physical barriers (landmarks), suggesting that other mechanisms restrict gene flow. It has been proposed that the extent of genetic structure in seabirds is best explained by relative overlap in non-breeding distributions of birds from different populations. We used results from the analysis of microsatellite DNA variation and geolocation (tracking) data to test this hypothesis. We studied three small (130-200 g), very abundant, zooplanktivorous petrels (Procellariiformes, Aves), each sampled at two breeding populations that were widely separated (Atlantic and Indian Ocean sectors of the Southern Ocean) but differed in the degree of overlap in non-breeding distributions; the wintering areas of the two Antarctic prion (Pachyptila desolata) populations are separated by over 5000 km, whereas those of the blue petrels (Halobaena caerulea) and thin-billed prions (P. belcheri) show considerable overlap. Therefore, we expected the breeding populations of blue petrels and thin-billed prions to show high connectivity despite their geographical distance, and those of Antarctic prions to be genetically differentiated. Results: Microsatellite (at 18 loci) and cytochrome b sequence data suggested a lack of genetic structure in all three species. We thus found no relationship between genetic and spatial structure (relative overlap in non-breeding distributions) in these pelagic seabirds. Conclusions: In line with other Southern Ocean taxa, geographic distance did not lead to genetic differences between widely spaced populations of Southern Ocean petrel species. [ABSTRACT FROM AUTHOR]

Seabirds can interact with marine litter, mainly by entanglement or ingestion. The ingestion of plastics can lead to starvation or physical damage to the digestive tract. For chicks, it could additionally lead to reduced growth, affecting survival and fledging. This study quantified the ingestion of plastics by seabird chicks via an opportunistic sampling strategy. When ringing is carried out at colonies, birds may spontaneously regurgitate their stomach contents due to the stress or as a defence mechanism. Regurgitates were collected from nestlings of three different species: Black-legged Kittiwake ( Rissa tridactyla , n = 38), Northern Fulmar ( Fulmarus glacialis , n = 14) and Great Cormorant ( Phalacrocorax carbo , n = 28). Plastic was present in all species, with the highest frequency of occurrence (FO) in Northern Fulmar chicks (28.6%), followed by Black-legged Kittiwakes (7.9%) and Great Cormorants (7.1%). The observed load of plastics on chicks, which have not yet left the nest, highlights the pervasive nature of plastic pollution. [ABSTRACT FROM AUTHOR]

Sexual size dimorphism and geographic variability in external measurements of the Grey-faced Petrel ( Pterodroma gouldi) were investigated on the west and east coasts of the North Island of New Zealand. The applicability of morphometrics to distinguish the sex of individuals in the two geographic areas and assign a geographic origin to individuals was evaluated. Low geographic variation in morphometry was found, with discriminant function analysis failing to develop an efficient function to assign a geographic origin (55.9% accuracy). In contrast, sexual size dimorphism was marked (up to 6.6% different), with males being significantly larger than females in all measurements but wing length. A discriminant function combining bill depth at nostrils and head length correctly predicted sex of adult breeders with 80.9% accuracy (78.9% for males, 82.7% for females). Despite its apparent applicability across the entire range of the species, this discriminant function was not sufficiently accurate on its own. Alternatively, the use of bill depth at the base or a bill size index increased sexing accuracy to 92.1% when both mates of pairs were considered. Thus, Grey-faced Petrels can be reliably sexed by taking only one measurement on both mates of a pair. [ABSTRACT FROM AUTHOR]

Collared Petrel Pterodroma brevipes and Gould's Petrel P. leucoptera are two closely related gadfly petrels that breed on islands in the Pacific Ocean. Pale individuals of the polymorphic Collared Petrel are remarkably similar to Gould's Petrel, so it is unsurprising that published descriptions of differences between the two species are incomplete or misleading. Museum specimens of both species and live Gould's Petrels were examined to identify diagnostic plumage characteristics. Pale Collared Petrels were most reliably distinguished from Gould's Petrels by their proportionally longer and tapered tail and by a clear contrast between the grey primaries and white primary coverts on the underwing. Pale Collared Petrels also exhibited a different pigment pattern on the side of the head; a subtle contrast between the breast sides and crown, which is absent in Gould's Petrel; a thicker dark trailing edge on the underwing; and a usually diffuse, rather than abrupt (as in Gould's Petrel), posterior edge of the breast patch. The presence of a collar across the upper breast was not diagnostic of intermediate Collared Petrels. Additional characteristics that may facilitate identification of some Gould's Petrels include a thinner dark ulnar-carpal bar on the underwing, prominent white blotches within the dark ulnar-carpal bar, and conspicuous white sides to the spread tail. [ABSTRACT FROM AUTHOR]

Endemic Westland petrels ( Procellaria westlandica ) are a remnant of extensive seabird populations that occupied the forested hill country of prehuman New Zealand. Because seabird guano is rich in Se, an often-deficient essential element, we proposed that Westland petrels enhance Se concentrations in ecosystems associated with their breeding grounds. We sampled terrestrial (soil, plants, riparian spiders) and freshwater (benthic invertebrates, fish) components from Westland petrel-enriched and non-seabird forests on the western coast of New Zealand's South Island, an area characterised by highly leached, nutrient-poor soils. Median seabird soil Se was an order of magnitude higher than soil from non-seabird sites (2.2 mg kg − 1 compared to 0.2 mg kg − 1 ), but corresponding plant foliage concentrations (0.06 mg kg − 1 ; 0.05 mg kg − 1 ) showed no difference between seabird and non-seabird sites. In streams, Se ranged from 0.05 mg kg − 1 (riparian foliage) to 3.1 mg kg − 1 (riparian spiders and freshwater mussels). However, there was no difference between seabird and non-seabird streams. Stoichiometric ratios (N:Se, P:Se) showed Se loss across all ecosystem components relative to seabird guano, except in seabird colony soil where N was lost preferentially. Seabirds therefore did not enrich the terrestrial plants and associated stream ecosystems in Se. We conclude that incorporation of trace elements brought ashore by seabirds cannot be assumed, even though seabirds are a significant source of marine-derived nutrients and trace elements to coastal ecosystems world-wide. [ABSTRACT FROM AUTHOR]

Here are proposed two automatic detectors of Barau's petrel ( Pterodroma baraui ) and tropical shearwater ( Puffinus bailloni ) vocalisations in noisy audio recordings (1) trained with a low number of positive training instances, and (2) whose performances would be the highest possible. To do so, acoustic recordings were performed in one Barau's petrel colony between February and May 2014 (85 h) and in two tropical shearwater colonies in March and April (21 h). Manual and automatic methods of segmentation were combined. Manual segmentation allowed (1) to miss a very few number of positive segments and (2) to avoid introducing false positive instances. Automatic segmentation provided quickly a diversified set of negative instances. Manual labelling must be regarded as an investment, for current and future works. A random forest classifier and classical methods of acoustic signal characterisation (cepstral coefficients, spectral moments, etc.) were tested. Best models were able to discriminate each target species calls from other sounds of its colony with F1 scores of 88% (Barau's petrel, 1015 samples) and 85% (tropical shearwater, 1217 samples). The acoustic monitoring of nocturnal burrow-nesting seabirds based on (1) data collected by autonomous recording units in harsh, windy and wet environments and (2) automatic analysis tools is feasible. The size of our database was limited. Consequently further works will be necessary to study robustness of models on long time-series data. [ABSTRACT FROM AUTHOR]

The southern giant petrel ( Macronectes giganteus) has a circumpolar distribution and breeds on subantarctic islands and a few continental Antarctic sites. Although this species has recently been down-listed to 'Least Concern' by the World Conservation Union (IUCN), there are strong fluctuations in abundance and variable long-term trends recorded at different sites. Systematic, long-term monitoring is essential to determine drivers underlying its population dynamics. Here, we examine long-term changes in population size and productivity of southern giant petrels at Signy Island, South Orkney Islands. Comparing estimated numbers of breeding pairs over the whole island in 2000/2001, 2005/2006, 2009/2010 and 2014/2015 with historical data revealed several phases of population change: a 64 % decline (6.2 % per annum) from 1968/1969 to 1984/1985, a 162 % increase (6.2 % per annum) to 2000/2001, stability until 2005/2006, a 56 % decline (18.3 % per annum) to 2009/2010 and stability until 2014/2015. This represents a 1.8 % decline per annum between 1968/1969 and 2014/2015. Annual counts within focal study areas suggested a more rapid increase from 1996/1997 to 2006/2007, but the same downward trend from 2006/2007 to present, underlining potential pitfalls in inferring trends from part-island counts. There was also a 20 % decline in breeding success from 1996/1997 to 2014/2015. Our results indicate substantial fluctuations in southern giant petrel abundance at Signy Island over 4-5 decades and a recent decline in breeding numbers and success. As the southern giant petrels breeding at the South Orkney Islands represents ~5-10 % of the global population, continuation of these declines would be of high conservation concern. [ABSTRACT FROM AUTHOR]

Determining the year-round distribution and behaviour of birds is necessary for a better understanding of their ecology and foraging strategies. Petrels form an important component of the high-latitude seabird assemblages in terms of species and individuals. The distribution and foraging ecology of three sympatric fulmarine petrels (Southern Fulmar Fulmarus glacialoides, Cape Petrel Daption capense and Snow Petrel Pagodroma nivea) were studied at Adélie Land, East Antarctica, by combining information from miniaturized saltwater immersion geolocators and stable isotopes from feathers. During the breeding season at a large spatial scale ( c. 200 km), the three species overlapped in their foraging areas located in the vicinity of the colonies but were segregated by their diet and trophic level, as indicated by the different chick δ15N values that increased in the order Cape Petrel < Southern Fulmar < Snow Petrel. During the non-breeding season, the three fulmarines showed species-specific migration strategies along a wide latitudinal gradient. Snow Petrels largely remained in ice-associated Antarctic waters, Southern Fulmars targeted primarily the sub-Antarctic zone and Cape Petrels migrated further north. Overall, birds spent less time in flight during the non-breeding period than during the breeding season, with the highest percentage of time spent sitting on the water occurring during the breeding season and at the beginning of the non-breeding period before migration. This activity pattern, together with the δ13C values of most feathers, strongly suggests that moult of the three fulmarine petrels occurred at that time in the very productive high Antarctic waters, where birds fed on a combination of crustaceans and fish. The study highlights different segregating mechanisms that allow the coexistence of closely related species, specifically, prey partitioning during the breeding season and spatial segregation at sea during the non-breeding season. [ABSTRACT FROM AUTHOR]

The diving capabilities of the Procellariformes remain the least understood component of avian diving physiology. Due to their relatively small size, shearwaters may have high oxygen consumption rates during diving relative to their available oxygen stores. Dive performance in this group should be strongly limited by the trade-off between oxygen consumption and oxygen stores, and shearwaters could be a good model group for testing predictions of dive theory. Many earlier measurements of shearwater dive behaviour relied on observations from the surface or potentially biased technology, and it is only recently that diving behaviour has been observed using electronic recorders for many of the clades within the family. The diving behaviour of Manx Shearwaters Puffinus puffinus breeding in Wales, UK, was studied on a large sample of birds using time-depth-temperature recorders deployed on chick-rearing shearwaters in July and August over 3 years (2009-2011). Light availability apparently limited diving as dives only occurred between 04:00 and 19:00 h GMT. All individuals routinely dived deeper than traditionally assumed, to a mean maximum depth of 31 m and occasionally down to nearly 55 m. We compiled all available data for a comparison of the dive depth across shearwater species. There was a positive allometric relationship between maximum dive depth and body mass across Puffinus and Ardenna shearwater species, as expected, but only if samples of fewer than two individuals were excluded. The large intra-specific range in maximum dive depth in our study illustrates that apparent diversity in diving performance across species must be interpreted cautiously. [ABSTRACT FROM AUTHOR]

Background: The flight patterns of albatrosses and shearwaters have become a touchstone for much of Lévy flight research, spawning an extensive field of enquiry. There is now compelling evidence that the flight patterns of these seabirds would have been appreciated by Paul Lévy, the mathematician after whom Lévy flights are named. Here we show that Lévy patterns (here taken to mean spatial or temporal patterns characterized by distributions with power-law tails) are, in fact, multifaceted in shearwaters being evident in both spatial and temporal patterns of activity. Results: We tested for Lévy patterns in the at-sea behaviours of two species of shearwater breeding in the North Atlantic Ocean (Calonectris borealis) and the Mediterranean sea (C. diomedea) during their incubating and chick-provisioning periods. We found that distributions of flight durations, on/in water durations and inter-dive time-intervals have power-law tails and so bear the hallmarks of Lévy patterns. Conclusions: The occurrence of these statistical laws is remarkable given that bird behaviours are strongly shaped by an individual's motivational state and by complex environmental interactions. Our observations could take Lévy patterns as models of animal behaviour to a new level by going beyond the characterisation of spatial movements to characterise how different behaviours are interwoven throughout daily animal life. [ABSTRACT FROM AUTHOR]

Polar Regions are experiencing environmental changes at unprecedented rates. These changes can spread throughout entire food webs from lower trophic levels to apex predators. As many top predators forage over large areas, these indirect effects may be associated with large-scale patterns of climate variability. Using global climate indices that are known to impact the Southern Ocean ecosystem (the El Niño Southern Oscillation and Antarctic Oscillation Indices) we assessed their efficacy to predict variation in the demographic parameters of Antarctic seabirds. First, we used a long-term dataset on adult survival (estimated from capture-mark-recapture data) and reproduction of Antarctic petrel Thalassoica antarctica, from the largest known breeding colony (Svarthamaren, Dronning Maud Land) and examined whether large-scale oceanographic fluctuations impact survival and reproduction. Second, we conducted an exhaustive literature review to determine whether the effects of large-scale environmental variability on Antarctic seabirds have a coherent fingerprint across the Antarctic continent and nearby islands. We found that most of the variation in both reproductive success, timing of hatching, and survival of Antarctic petrels can be accurately modeled using the two modes of large-scale climate variability in Antarctica. The literature review, combined with the results from our field study, suggests that while the anticipated trends in the global patterns of climatic variability will generally have detrimental effects on populations of top predators in the Southwest Atlantic, these conclusions cannot be extrapolated to all seabird populations in Antarctica without additional data. [ABSTRACT FROM AUTHOR]

The ingestion of plastic by seabirds has been used as an indicator of population and ocean health. However, few studies have examined adults and juveniles of the same species concurrent with the availability of plastic in the local marine environment. In King George Sound (KGS), Western Australia, 13% of adult flesh-footed shearwaters ( Ardenna carneipes ) and 90% of fledglings contained plastic items in their digestive tract. On Lord Howe Island (LHI), New South Wales, 75% of adult shearwaters and 100% of fledglings contained plastic. Ingested items were assessed using Jaccard's Index (where J = 0 indicates complete dissimilarity and J = 1 complete similarity). The colour of items ingested by self- and chick-provisioning shearwaters from KGS exhibited broad overlap with plastic available in the local environment ( J = 0.78–0.80), and plastic in adults and fledglings from LHI were less similar to those available ( J = 0.31–0.58). Additional data on seabird colour selection would improve our understanding of the factors influencing the behaviour of ingesting plastic, and its contribution to the decline of some species. [ABSTRACT FROM AUTHOR]

In the 1980s, penguins dominated the prey remains of sub-Antarctic skuas Stercorarius antarcticus breeding on Marion Island, whereas on neighbouring Prince Edward Island burrowing petrels made up >95% of prey remains in nest middens. This difference resulted at least in part from the impact of introduced cats Felis catus on Marion Island’s burrowing petrel populations. Cats were introduced to Marion Island in 1949, and prior to their eradication in 1991, they killed an estimated 450 000 petrels each year, greatly reducing the densities of petrels breeding on the island. A repeat survey of skua prey remains showed that penguins still dominated the prey of breeding sub-Antarctic skuas on Marion Island in the summer of 2010–11, two decades after cats were eradicated from the island. The proportion of penguin remains decreased slightly compared to 1987–88, but this might be expected given the decreases in penguin numbers on Marion Island over this period. Regurgitated pellets confirmed the dominance of penguin prey on Marion Island. Taken together with the decrease in skua numbers on Marion Island over the last two decades, our results suggest that there has been little recovery in the population of at least summer-breeding burrowing petrels since cats were eradicated. [ABSTRACT FROM AUTHOR]

The Soft-plumaged Petrel is a gadfly petrel that occurs widely across the southern oceans and exhibits plumage polymorphism. Palebellied individuals make up the vast majority of the species, while dark individuals are relatively rare. Intermediate forms are rarer still and, according to some authors, known only from museum specimens. We describe a number of at-sea records of intermediate-plumaged individuals seen off southwest Western Australia, including a previously undocumented streaked variant. Our observations indicate that plumage polymorphism within the species covers a continuous spectrum of variation between typical pale and wholly dark individuals. [ABSTRACT FROM AUTHOR]

Burrow-nesting seabird populations are vulnerable to predation by introduced rats, because of their nesting habits and slow life histories. We investigated whether control of kiore (Pacific rats,Rattus exulans) by removal trapping, and during an unsuccessful community-led island-wide eradication attempt, had any effects on nest survival of grey-faced petrels (Pterodroma gouldi) on Ririwha (Stephenson Island), northeastern New Zealand. We compared nest survival between two plots at which rats were trapped and six un-trapped plots in 2010, as well as at all plots during and after the poisoning programme in 2011–2012. Neither mean rates of breeding burrow occupancy nor nest survival differed between trapped and un-trapped plots in 2010. We found no significant differences between years or between plots throughout the poisoning programme. Extrapolation of daily nest survival rates to the full 172-day combined egg and chick period gave an estimate of mean annual productivity for all plots combined of 0.285 (95% confidence interval 0.252–0.318), which is higher than on comparable predator-free islands. Although the absence of a detectable effect of kiore on breeding grey-faced petrels on Ririwha is reassuring, we can be less sure that smaller burrow-nesting seabirds on the island are secure. [ABSTRACT FROM PUBLISHER]

The paucity of leaf litter in seabird forest is usually explained by litter burial in burrows, but burial by itself fails to address the processes controlling decomposition. We measured soil microbial C in samples from a Westland petrel ( Procellaria westlandica ) colony both within and outside the breeding season, and compared the results with two non-seabird forests. From the few studies of seabird soil microbial C, we initially hypothesised a soil microbial C concentration sequence of occupied burrows > unoccupied burrows > adjacent forest floor > non-seabird forest. Instead, the highest values came from non-seabird forest, a pattern consistent with published meta-analyses on the effects of N addition. Within the colony, highest concentrations were in forest floor soil and there was no burrow occupation effect. However, seabird forest soil microbial C followed a strong inverse relationship with soil δ 13 C ( r = −0.58; P < 0.001) as well as the expected relationship with total soil C ( r = 0.75); the relationship with soil δ 13 C in non-seabird forest was not significant ( P = 0.29). We propose that soil microbes in seabird forest repeatedly process a single pool of increasingly refractory terrestrial soil C, facilitated by seabird guano priming of organic matter mineralisation. In this context, the paucity of leaf litter in seabird forest can be seen as a consequence of microbial C limitation in a nutrient-saturated system, an explanation consistent with recent theory. [ABSTRACT FROM AUTHOR]

Background and aims: Although the nutrient enrichment literature emphasises anthropogenic sources, seabirds deposit large quantities of marine detritus at breeding and roosting sites. Little is known of the chemical fractions and plant availability of seabird soil nutrients and their relationship to nutrient limitation patterns. Methods: Nutrients in mineral soil from a breeding colony of burrowing seabirds were progressively depleted by growing radiata pine ( Pinus radiata D. Don.) and wheat ( Triticum aestivum) separately in small pots over 4-10 months. Soil from destructively sampled pots was analysed using a version of the Hedley fractionation scheme; foliage was analysed for C, N and δN using isotope ratio mass spectrometry, and for P using microwave assisted digestion and ICP-OES. Results: Foliar C:N and δN increased with plant mass for both species, but N:P remained constant within plants of each species. As total soil P was progressively depleted, concentrations of bicarbonate-extractable soil P were maintained. This occurred mainly by depletion of non-labile inorganic P forms, thus demonstrating potential mobilisation of all refractory P (as defined by our chemical fractionation method) into plants growing at the seabird site. The increasing foliar δN was consistent with the progressive mobilisation of more highly recycled forms of N. Conclusions: We infer a species-specific stoichiometric homeostasis for N and P in plants grown in seabird soil, facilitated by mobilisation of recalcitrant forms of soil N and P. [ABSTRACT FROM AUTHOR]

Until recent decades, details of the migratory movements of seabirds remained largely unknown owing to the difficulties in following individuals at sea. Subsequent advances in biologging technology have greatly increased our knowledge of seabird migration and distribution, particularly of highly pelagic species. Short-tailed Shearwaters (Ardenna tenuirostris) (~500 g) have been studied extensively during their breeding season but our understanding of their movements outside this period remains poor. Here, we present the first tracks of the trans-equatorial migration of Short-tailed Shearwaters from a colony on Great Dog Island, Tasmania, Australia. Data were obtained from global location sensors (GLS loggers or geolocators), which enable the estimation of location twice per day based on ambient light levels. After breeding, tracked Shearwaters flew south of the Antarctic Polar Front to a previously unknown stopover site, where they remained for several weeks, before travelling rapidly northward through the western Pacific Ocean to coastal waters off Japan. Short-tailed Shearwaters spent the bulk of the northern hemisphere summer, either in this region or further north in the Bering Sea, before returning south through the central Pacific to their breeding sites. Our results, for the first time, describe in detail the complete migration of this long-lived seabird, reveal individual variation in timing and distribution, and describe the environmental characteristics of their key non-breeding habitats. [ABSTRACT FROM AUTHOR]

Light pollution is increasing around the world and altering natural nightscapes with potential ecological and evolutionary consequences. A severe ecological perturbation caused by artificial lights is mass mortalities of organisms, including seabird fledglings that are attracted to lights at night on their first flights to the sea. Here, we report on the number of fledging short-tailed shearwaters Ardenna tenuirostris found grounded in evening and morning rescue patrols conducted at Phillip Island, Australia, during a 15-year period (1999–2013). We assessed factors affecting numbers of grounded birds and mortality including date, moon phase, wind direction and speed, number of visitors and holiday periods. We also tested experimentally if birds were attracted to lights by turning the lights off on a section of the road. Of 8871 fledglings found, 39% were dead or dying. This mortality rate was 4–8 times higher than reported elsewhere for other shearwater species, probably because searching for fledglings was part of our systematic rescue effort rather than the opportunistic rescue used elsewhere. Thus, it suggests that light-induced mortality of seabirds is usually underestimated. We rescued more birds (dead and alive) in peak fledging, moonless and windy nights. Mortality increased through the fledging period, in the mornings and with increased traffic on holiday periods. Turning the road lights off decreased the number of grounded birds (dead and alive). While moon, wind and time are uncontrolled natural constraints, we demonstrated that reduction of light pollution and better traffic management can mitigate artificial light-induced mortality. [ABSTRACT FROM AUTHOR]

To study habitat use and at-sea movements of southern giant petrels (SGP) during non-breeding period, we deployed 15 satellite transmitters (six adults, nine juveniles) at Isla Arce and Isla Gran Robredo colonies in Patagonia, Argentina. Birds were instrumented during 81.4 ± 37 days. Adult birds used 74% of the Argentine shelf concentrating mainly at the shelf break, middle shelf waters, and the surroundings of the colony. After fledging, juveniles spread to the Argentine, Uruguayan and Brazilian shelves within the South Atlantic. Adults alternated at-sea excursions (12 ± 5 days) with periods at the colony of 3 ± 0.3 days. Contrarily, juveniles moved first to the shelf break and then traveled northwards reaching the south of Brazil. There was some spatial overlap between age classes, but only during the first 30 days after juveniles had fledged; thereafter there was not overlap between the areas used by both age classes. The Argentine shelf is widely used by different species offering a suitable environment for foraging; this may be why adults SGP from Patagonian colonies spend all year-round within the Argentine shelf. The identification of used areas of non-breeding SGP fills a gap in the species knowledge contributing not only to the preservation the species, but also to the management of marine areas globally recognized as important for many other Procellariiformes. [ABSTRACT FROM AUTHOR]

Many procellariiforms use olfactory cues to locate food patches over the seemingly featureless ocean surface. In particular, some of them are able to detect and are attracted by dimethylsulphide (DMS), a volatile compound naturally occurring over worldwide oceans in correspondence with productive feeding areas. However, current knowledge is restricted to sub-Antarctic species and to only one study realized under natural conditions at sea. Here, for the first time, we investigated the response to DMS in parallel in two different environments in temperate waters, the Atlantic Ocean and the Mediterranean Sea, employing Cory's (Calonectris borealis) and Scopoli's (Calonectris diomedea) shearwaters as models. To test whether these birds can detect and respond to DMS, we presented them with this substance in a Y-maze. Then, to determine whether they use this molecule in natural conditions, we tested the response to DMS at sea. The number of birds that chose DMS in the Y-maze and that were recruited at DMS-scented slicks at sea suggests that these shearwaters are attracted to DMS in both non-foraging and natural contexts. Our findings show that the use of DMS as a foraging cue may be a strategy adopted by procellariiforms across oceans but that regional differences may exist, giving a worldwide perspective to previous hypotheses concerning the use of DMS as a chemical cue. [ABSTRACT FROM AUTHOR]

Palaeontological studies show that three endemic procellariid seabird species became extinct on the remote island of St Helena in the South Atlantic Ocean. At least one of these, Pterodroma rupinarum Olson, 1975, is likely to have survived until human colonization of the island, although it is known only from subfossil bones. Several species of Pterodroma are distributed across the Atlantic, but the skull and bill of Pt. rupinarum were judged to be more similar to the Indo- Pacific Pterodroma rostrata group, which was recently split into the separate genus Pseudobulweria. We used ancient DNA techniques to sequence the mitochondrial cytochrome b gene of the extinct Pt. rupinarum, and conducted phylogenetic analyses to investigate the placement of this enigmatic taxon. In trees constructed using maximum likelihood and Bayesian inference, Pt. rupinarum did not group with Pseudobulweria, but instead fell within a strongly supported clade of Atlantic Pterodroma, including the endangered Black-capped [ Pterodroma hasitata ( Kuhl, 1820)] and Bermuda [ Pterodroma cahow ( Nichols & Mowbray, 1916)] petrels, as well as the Macaronesian petrels [ Pterodroma madeira Mathews, 1934, Pterodroma feae (Salvadori, 1899) and Pterodroma deserta Mathews, 1934]. Pterodroma rupinarum shared a particularly close relationship with Pt. feae of the Cape Verde Islands, which is also the geographically closest species within the clade. Considering the osteological distinctiveness of Pt. rupinarum it was probably a separate species, or at least a highly diverged population that was isolated for a substantial period of time prior to its extinction. © 2013 The Linnean Society of London [ABSTRACT FROM AUTHOR]