Field characters and behaviour at sea of giant petrels in relation to their oceanic distribution

Abstract

The distinctive field characters of Macronectes halli and M. giganteus are described. Records of giant petrels observed from ships travelling between Australia, Macquarie Island and Antarctica in summer show that halli tends to follow ships whereas giganteus tends not to do so. With this difference in behaviour as an aid to identifying these otherwise similar species, it is shown that from November to March, halli occurs mostly to the north of the Antarctic Convergence and giganteus mostly to the south. Earlier literature is reviewed in relation to these findings.