Breeding parameters of the Sooty Shearwater (Ardenna grisea) on Long Island, New Zealand

Abstract

The Sooty Shearwater (Ardenna grisea) is one of the better studied petrels of New Zealand. Although one of New Zealand's most abundant seabirds, smaller populations of Sooty Shearwaters may be less resilient to stochastic events in the long term. We investigated aspects of the breeding biology of Sooty Shearwaters and burrow dynamics on Long Island, in the Marlborough Sounds, New Zealand, from November 2008 to May 2009. Burrows were usually simple and unbranched, with an average length of 83.6 cm (s.e. 4.3 cm). The incubation period was 54.3 days (s.e. 1 day) and the nestling period 104.5 days (s.e. 2 days). Breeding success was 40.1%, within the range expected based on published studies of other populations of Sooty Shearwaters and of congeners. This study paves the way for further investigation into the viability and persistence of a small island population.