Breeding Biology of Blue-Petrels Halobaena caerulea at the Prince Edward Islands

Abstract

Blue Petrels breed in dense, often large, colonies at the Prince Edward Islands. They are summer-breeding burrowing petrels and are absent from the islands during June to August. Moult occurs at sea after breeding and takes 83- 13 1 days. The mean laying and hatching dates were 23 October and 9 December respectively; chicks fledged between 25 January and 14 February. Wing, culmen and tarsus length growth curves are described for 43 chicks. The mean peak mass of the nestlings was c. 210 g at about 40 days of age. The distributions of Blue Petrel colonies are given for both Marion and Prince Edward Islands; the species is more abundant at the latter island, which is free of cats. Burrowing petrels have suffered severely from cat predation at Marion Island and the future of the Blue Petrel population is discussed.