Academic literature on the topic 'Pelecanoides'

The difference between the larvae of Eurypharynx pelecanoides and Saccopharynx ampullaceus, both belonging to the suborder Saccopharyngoidei (formerly Lyomeri), does not consist only of different numbers in myomeres but also of the structure of the suspensorium of the lower jaw. In E. pelecanoides it consists of two separate bones, the hyomandibulare and the quadratum. According to Orton (1963) in S. ampullaceus the suspensorium consists of only one piece of bone.

Although there is increasing evidence that climatic variations during the non-breeding season shape population dynamics of seabirds, most aspects of their winter distribution and ecology remain essentially unknown. We used stable isotope signatures in feathers to infer and compare the moulting (wintering) habitat of subantarctic petrels breeding at two distant localities (South Georgia and Kerguelen). Petrels showed species-specific wintering habitat preferences, with a similar pattern of latitudinal segregation for all but one taxon. At both localities, δ 13 C values indicated that blue petrels ( Halobaena caerulea ) moult in Antarctic waters, South Georgian diving petrels ( Pelecanoides georgicus ) in the vicinity of the archipelagos and/or in the Polar Frontal Zone and Antarctic prions ( Pachyptila desolata ) in warmer waters. In contrast, common diving petrels ( Pelecanoides urinatrix ) showed divergent strategies, with low and high intrapopulation variation at South Georgia and Kerguelen, respectively. Birds from Kerguelen dispersed over a much wider range of habitats, from coastal to oceanic waters and from Antarctica to the subtropics, whereas those from South Georgia wintered mainly in waters around the archipelago. This study is the first to show such striking between-population heterogeneity in individual wintering strategies, which could have important implications for likely demographic responses to environmental perturbation.

The Peruvian diving petrel Pelecanoides garnotii is endemic to the Peruvian or Humboldt Current. Descriptions of past colonies suggest that the species was once abundant in Peru, but harvesting guano on its nesting islands and killing the birds for their meat caused a drastic decline in the population. Fishing activities and direct exploitation threaten the only two remaining breeding colonies in Peru. There are an estimated 4000 breeding individuals left, but unless they are protected the species will continue to decline.

Chick feeding in common diving petrels (Pelecanoides urinatrix exsul) and South Georgia diving petrels (P. georgicus) was studied on Bird Island, South Georgia. Complete chick meals removed from the proventriculus of adults averaged 25.5 g (n = 32) for common diving petrels (17.6% of adult mass) and 23.3 g (n = 24) for South Georgia diving petrels (20.2% of adult mass); neither contained stomach oils. The sum of the positive mass increments during overnight weighings (SUM) averaged 48.6 g for common diving petrel chicks (n = 78 chick nights) and 41.6 g for South Georgia diving petrel chicks (n = 78 chick nights). Average adult feeding frequencies were 0.95 meals day−1 and 0.92 meals day−1, respectively. Relative meal size in diving petrels was similar to that of other procellariiforms, but SUM averaged about twice that of other petrels. The lower conversion efficiency of meals to body mass in diving petrel chicks reflects the absence of stomach oils in the diet. Higher chick feeding frequency and lower variance in SUM are consistent with the hypothesis that diving petrels forage nearshore on reliable food supply compared with other procellariiforms.

L'exploration de la niche écologique d'une espèce implique une analyse à plusieurs échelles, car différentes contraintes environnementales peuvent avoir des conséquences écologiques importantes. Cependant, l'absence d'informations précises sur l'écologie des petites espèces de procellariiformes a considérablement limité leur étude, impactant notre capacité à définir une planification de conservation appropriée. Les avancées technologiques dans la miniaturisation des enregistreurs de données permettent depuis peu de collecter des données écologiques sur ces espèces. Dans cette étude, une approche multidisciplinaire a été utilisée pour étudier la niche écologique des pétrels plongeurs communs et de Géorgie du Sud. Les principaux objectifs étaient de : 1) décrire leur écologie alimentaire pendant les périodes de reproduction et de non-reproduction, et étudier leurs variations interannuelles ; 2) déterminer les différences écologiques entre les populations de l'Océan Austral ; et 3) étudier les variations de leur écologie tout au long du cycle annuel dans un contexte de ségrégation écologique entre ces deux espèces sœurs. Les résultats ont démontré que les pétrels plongeurs présentent des capacités de vol remarquables malgré leur charge alaire élevée, se nourrissant sur de vastes zones pendant la reproduction et migrant à plusieurs milliers de kilomètres de leur colonie pendant la période post-reproduction. Ces analyses ont révélé d'importantes différences écologiques au sein des espèces, notamment en termes de phénologie et de zone de migration. La collecte de données sur plusieurs années a considérablement renforcé ces résultats et fournit des informations précieuses pour comprendre les limites des niches écologiques des pétrels plongeurs. Enfin, la variation de ségrégation en fonction du stade de reproduction a démontré l'importance d'une approche multi-outils pour mieux décrire et comprendre la coexistence d'espèces écologiquement similaires
Exploring a species’ ecological niche entails investigating at multiple scales, as different environmental threats and niche constraints between intra-species levels may lead to important ecological and conservation consequences. However, the absence of precise information about small procellariiform species ecology has greatly limited ecological niche modelling studies, directly impacting our ability to delineate proper conservation planning. Technological advancements in the miniaturisation of data loggers have made it possible to collect ecological data of such species. In the present study, a multi-tooled approach was used to investigate the ecological niche of the common and the South-Georgian diving petrels. The primary objectives were to: 1) describe their foraging ecology during the breeding and non-breeding periods, and investigate their inter-annual variations; 2) determine the ecological differences between populations throughout the Southern Ocean; and 3) study the variations in their foraging ecology throughout the entire annual-cycle in the context of niche segregation between two sibling species. The results demonstrated that diving petrels exhibit remarkable flying abilities despite their high wing loading, foraging over large areas during the breeding season, and migrating several thousands of kilometres from their colony during the post-breeding period. These analyses revealed important ecological differences throughout the species distribution, particularly in terms of phenology and migration area. Collecting data over several years substantially strengthens results and provides valuable information to understand the variations and the limits of diving petrel ecological niches. Finally, a stage-dependent and context-dependent niche segregation analysis demonstrated the importance of a multi-tooled approach to better describe and understand the co-existence of ecologically similar species