Search

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 13 C) and nitrogen (δ 15 N) 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 13 C. 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., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

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., (© 2024. The Author(s).)

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., (© 2021. The Author(s).)

This study reports the case of a Manx shearwater (Puffinus puffinus) that died from avian malaria while under care at a rehabilitation center in Espírito Santo, Brazil. The bird was rescued on October 2018, and remained under care until it died suddenly on January 2019. A blood smear produced 8 days before death was negative for parasites, whereas a blood smear produced post-mortem revealed a high parasitemia by a parasite resembling Plasmodium cathemerium. The sequence of a 412 bp segment of the cyt-b gene was identical to that of lineage PADOM09, and phylogenetic analysis corroborated that this parasite was closely-related to known lineages of P. cathemerium. The acuteness and severity of the infection documented in this case suggest that seabirds of the order Procellariiformes might be highly susceptible to Plasmodium infections, raising the concern that avian malaria may present a significant threat to their conservation., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

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.

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 (2.2mgkg -1 compared to 0.2mgkg -1 ), but corresponding plant foliage concentrations (0.06mgkg -1 ; 0.05mgkg -1 ) showed no difference between seabird and non-seabird sites. In streams, Se ranged from 0.05mgkg -1 (riparian foliage) to 3.1mgkg -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., (Copyright © 2016 Elsevier B.V. All rights reserved.)