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Foraging strategies of grey-headed albatrosses Thalassarche chrysostoma: Integration of movements, activity and feeding events
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Orientador(es)
Resumo(s)
We identified a range of foraging strategies adopted by grey-headed albatrosses Thalassarche
chrysostoma rearing chicks at Bird Island, South Georgia, by simultaneously using satellite
telemetry, wet/dry activity recorders and stomach temperature loggers. The albatrosses foraged
mostly over oceanic waters, probably associated with the Polar Front north of South Georgia, and also
over shelf-slope waters around the Antarctic Peninsula. After leaving the colony, birds commuted to
areas with predictable prey concentrations, where they remained for several days. During search
periods, birds landed more often and had a higher intake rate, but spent the same proportion of time
in flight as on commuting days. Although intake rates were particularly high in shelf-break waters
around the Antarctic Peninsula (only one individual foraged in this area), prey were also consumed
in reasonable quantities during commuting flights. While at sea, birds spent most (81%) of the day
flying, and most (94%) of the night resting on the water. A considerable proportion (26% by mass) of
prey was consumed during darkness. The majority of prey were detected and captured during search
flights, but 35% were located while sitting on the sea surface. Many ingestion events (up to 27% of
the overall food intake) showed temperature signatures characteristic of fluids, suggesting that albatrosses
may feed on gelatinous and rapidly digested prey (e.g. salps and jellyfish) much more often
than previously suspected. Diet samples delivered to the chicks comprised mostly squid (particularly
Martialia hyadesi) and Antarctic krill Euphausia superba.
Descrição
Palavras-chave
Seabird Feeding behaviour Stomach temperature Salp Jellyfish South Georgia
Contexto Educativo
Citação
Marine Ecology Progress Series, 280, 261-273