Search

The objective of this work is to estimate the size of the colony of wedge-tailed shearwaters Ardenna pacifica on the Pindaï peninsula on the west coast of Grande Terre (New Caledonia’s main island, Coral Sea), based on 12 census operations by the local ornithological association between 2002 and 2016. Each census operation consisted of a systematic count of burrows along multiple transects crossing the colony. The colony extended along the 1.24 km of the southern beach of the peninsula and its total estimated area was 16.5 ha. Estimated number of burrows in the colony varied across breeding seasons from 10,700±1,300 to 26,100±2,700. Colony size was strongly correlated with mean burrow density but not with the surface occupied by active burrows. The colony harbours >1% of the known global numbers of this species. Fluctuations in colony size from one season to the next are explained by fluctuations in the proportion of breeding individuals. This proportion possibly depends on the abundance of available prey. The numerical importance of the Pindaï colony engages the responsibility of the competent authorities with regard to the conservation of the species. Suggestions are proposed to managers., L’objectif du présent travail est l’estimation de la taille de la colonie de puffins du Pacifique Ardenna pacifica de la péninsule de Pindaï sur la côte ouest de la Grande Terre de la Nouvelle-Calédonie (mer de Corail), à partir de douze opérations de recensement effectuées entre 2002 et 2016 par l’association ornithologique locale. Chaque opération de recensement consistait en un comptage systématique des terriers le long de multiples transects traversant la colonie. Celle-ci s’étendait tout au long des 1,24 km de la plage sud de la péninsule et sa surface totale estimée était 16.5 ha. L’estimation du nombre de terriers de la colonie variait, d’une saison de reproduction à l’autre, de 10 700 ± 1 300 à 26 100 ± 2 700. La taille de la colonie était fortement corrélée à la densité moyenne de terriers mais pas à la surface occupée par les terriers actifs. La taille maximale de la colonie représente > 1 % des effectifs mondiaux connus de cette espèce. Les fluctuations, d’une saison à l’autre, de la taille de la colonie s’expliquent par des fluctuations dans la proportion d’individus capables de se reproduire, cette proportion dépendant possiblement de l’abondance des proies disponibles. L’importance numérique de la colonie de Pindaï engage la responsabilité des autorités compétentes vis-àvis de la conservation de l’espèce. Des recommandations sont proposées à l’attention des gestionnaires.

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.

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

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.

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.

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 clea

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.

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.

Ten novel polymorphic microsatellite loci were isolated and characterized from the Balearic shearwater (Puffinus mauretanicus), a critically endangered seabird. The developed loci revealed a relatively low number of alleles per locus, as well as low levels of polymorphism (HO = 0.377 ± 0.241). One of the loci appeared to be W-linked. All polymorphic loci were successfully amplified in its closely related species, the Yelkouan shearwater (Puffinus yelkouan). These microsatellite markers would be useful for assessing population structure in the Balearic shearwater and the possible hybridization process between both shearwaters species

Breeding strategies of two closely related fulmarine petrels were studied on Ardery Island, on the continental coast of East Antarctica, where short summers are expected to narrow the time-window for reproduction. Both species had a similar breeding period (97 days from laying to fledging) but Antarctic Petrels Thalassoica antarctica bred up to 16 days earlier than Southern Fulmars. During the pre-laying exodus, all Antarctic Petrels deserted the colony, whereas some Southern Fulmars Fulmarus glacialoides remained. Antarctic Petrels exhibited stronger synchronization in breeding, made longer foraging trips and spent less time guarding their chicks than Southern Fulmars. Overall breeding success of both species was similar but failures of Antarctic Petrels were concentrated in the early egg-phase and after hatching, when parents ceased guarding. Southern Fulmars lost eggs and chicks later in the breeding cycle and so wasted more parental investment in failed breeding attempts. Different breeding strategies may be imposed by flight characteristics; Southern Fulmars are less capable of crossing large expanses of pack ice and need to delay breeding until the sea ice retreats and breaks up. However, due to the short summer they risk chick failure when weather conditions deteriorate late in the season.

Wekas were considered to have a deleterious effect on the petrels on Codfish Island. Wekas were captured and taken to Stewart Island, the method for which is outlined in the report. The removal of a few birds may be insignificant in the long term but may be enough to help diminish the toll of mottled petrels by weka predation. Additional notes to the report by Walls and Walker 1978 on bird activities is included along with some information on bats. Three aspects on vegetation were found; 1) further areas of Stilbocarpa with no possum damage were found, 2) possums appear to have damaged southern rata trees, 3) burrowing seabirds appear to cause unfavourable conditions for trees. It is recommended that Codfish Island be modified as little as possible by humans. (auth)

Beknopte informatie over het broedgedrag en voedering van Antarctische- (Thalassoica antarctica) en grijze stormvogels (Fulmares glacialoides)

Beknopte informatie van Wageningen UR over het eetgedrag van de Kaapse Stormvogel (Dapsion Capense) en de Sneeuwstormvogel (pagodroma nivea)