Diet and feeding ecology of blue petrels Halobaena caerulea at Iles Kerguelen, Southern Indian Ocean

Abstract

The food and feeding ecology of the blue petrel Halobaena caerulea was investigated over 4 consecutive chick-rearing periods at Iles Kerguelen. In all years, blue petrels fed on a large diversity of crustaceans and fish, with a small proportion of squid and other organisms. Crustaceans ranked first by number (98%) and second by reconstituted mass (37%). The hyperiid Themisto gaudichaudii and the euphausiid Thysanoessa sp. were the dominant prey items, accounting each for 42% by number, and for 12 and 4% by mass of the diet, respectively. Other important crustacean prey were the Antarctic krill Euphausia superba (2% by number and 10% by mass) and the large shrimp Pasiphaea scotiae ( 1000 km from the breeding colonies, but blue petrels also foraged on their way back to Iles Kerguelen from these distant foraging grounds to feed their chicks. A comparison of the stable carbon and nitrogen isotopic compositions of chick and adult feathers reveals that adult blue petrels fed at the same trophic level during the chick-rearing and moulting period, and that they renew their flight feathers in Antarctic waters.