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Foraging partitioning between giant petrels Macronectes spp. and its relationship with breeding population changes at Bird Island, South Georgia

2000; Inter-Research; Volume: 204; Linguagem: Inglês

10.3354/meps204279

1616-1599

Jacob González‐Solís, J. P. Croxall, AG Wood,

Genetic and phenotypic traits in livestock

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 204:279-288 (2000) - doi:10.3354/meps204279 Foraging partitioning between giant petrels Macronectes spp. and its relationship with breeding population changes at Bird Island, South Georgia Jacob González-Solís*, John P. Croxall, Andy G. Wood British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 OET, United Kingdom *Present address: Dept Biologia Animal (Vertebrats), Universitat de Barcelona, Av. Diagonal 645, 08028 Barcelona, Spain. E-mail: jacob@porthos.bio.ub.es ABSTRACT: We satellite-tracked the foraging trips of males and females of the 2 sibling species of giant petrels, Macronectes halli and M. giganteus, breeding sympatrically at Bird Island (South Georgia, Antarctica), during the incubation period (November-December). Size of the activity range in addition to speed and distance covered on foraging trips were similar between the species, but were lower for males than for females in both species. Sex-specific differences agree with previous observations on diets and on attendance at seal carcasses, suggesting that females mainly forage at sea, whereas males mainly scavenge on the coast. Overall, however, the foraging ecology of both species seems very similar. Interspecific and intersexual competition may be reduced by the limited overlap in the at-sea range, with southern giant petrels foraging further south than did northern giant petrels, and females further west than males, suggesting some spatial partitioning in foraging areas. Male northern giant petrels foraged almost exclusively on the South Georgia coast; their strong dependence during the brooding and chick-rearing period on Antarctic fur seals, whose population has increased exponentially in recent years, may be reflected in the recent population increase of northern giant petrels at South Georgia. Foraging areas of giant petrels overlapped extensively with longline fishery distribution, highlighting their susceptibility to being caught on longline hooks. Females were at higher risk during the study period since they made longer trips and foraged further west than males, into areas where local longline fisheries are more active. KEY WORDS: Spatial segregation · Activity range overlap · Satellite tracking · Kernel analysis · Longline fishery · Seabird-fisheries interactions Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 204. Online publication date: October 05, 2000 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2000 Inter-Research.