Diet of grey-headed albatrosses at the Diego Ramirez Islands, Chile: ecological implications

The diet of grey-headed albatrosses at Diego Ramirez 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 Martiali...

Full description

Bibliographic Details
Published in:Antarctic Science
Main Authors: Arata, Javier, Robertson, Graham, Valencia, José, Xavier, José C., Moreno, Carlos A.
Format: Article in Journal/Newspaper
Language:English
Published: Cambridge University Press 2004
Subjects:
Online Access:http://nora.nerc.ac.uk/id/eprint/12095/
https://nora.nerc.ac.uk/id/eprint/12095/1/download.pdf
http://journals.cambridge.org/download.php?file=%2FANS%2FANS16_03%2FS095410200400207Xa.pdf&code=4821bb1ae6129c42c3e652438a6bb5dd
Description
Summary:The diet of grey-headed albatrosses at Diego Ramirez 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 Ramirez. 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 Ramirez 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.