Breeding biology of the Flesh-footed Shearwater (Puffinus carneipes) on Woody Island, Western Australia

Abstract

The Flesh-footed Shearwater (Puffinus carneipes) is a pelagic seabird that breeds predominantly around southern Australia and New Zealand. Its breeding biology is poorly known, particularly in Western Australia where the species is known to have suffered mortality during long-line fishing operations. We studied the breeding biology of the Flesh-footed Shearwater on Woody Island, off the southern coast of Western Australia, between 2000 and 2003, from the post-migratory return of adults to the colony until the departure of the last fledglings 7 months later. Shearwaters dug single-tunnelled burrows slightly over 1 m long (1050 ± 16 mm (s.e.)) in soil >350 mm deep, during October, before embarking on an unsynchronised pre-laying exodus through November. Eggs were laid in the last week of November, and incubated over 54 ± 7 days during December and January, before hatching in mid- to late January. The fledglings left in late April–early May after spending an average 101 ± 0.9 days in the burrow. A logistic growth model, fitted to weekly measurements of skeletal body components, determined that the head, bill and tarsus grew rapidly during early burrow life, while growth of the wing was slow initially and remained incomplete at fledging. Breeding success was measured as 40% and 53% for two successive seasons, and was greater from burrows on a medium gradient than those on slighter gradients in both seasons. Although baseline data are provided here, longer term studies addressing specific demographic parameters, such as adult survival, juvenile recruitment and fecundity, are needed to assess the population status and guide management actions.