Diet of grey-headed albatrosses at the Diego Ramírez Islands, Chile: ecological implications
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Date
2004
Journal Title
Journal ISSN
Volume Title
Publisher
Cambridge Universty Press
Abstract
The diet of grey-headed albatrosses at Diego Ramírez was analysed and compared to that of the
sympatric black-browed albatross. Diet composition was inferred from an analysis of prey hard parts present
in 103 chick regurgitates obtained during breeding seasons 2000, 2001 and 2002. The squid Martialia
hyadesi predominated in the diet samples in 2001 and 2002 (89% and 81% of reconstituted mass), but was
absent from the 2000 samples. Reconstituted mean mass per sample in 2000 was significantly lower than in
2001 and 2002. Chick growth rate during 2000 was also the lowest recorded. This suggests that M. hyadesi
plays an important role in the breeding performance of grey-headed albatrosses at Diego Ramírez. Low
presence of M. hyadesi in grey-headed albatrosses’ diet at South Georgia in 2000, a year with significant low
breeding success, suggests ocean-wide processes affecting the availability of this prey to both populations
simultaneously. Overlap in diet composition, and inferred feeding areas, between the sympatric albatross
species at Diego Ramírez was minimal. Grey-headed albatrosses fed mainly on species associated with the
Antarctic Polar Front, whereas black-browed albatrosses consumed benthopelagic species frequently caught
in fishing operations in southern Chile.
Description
Keywords
Ciencia, Grey-headed albatrosses, Albatros
Citation
Antarctic Science 16 (3): 263–275 (2004)