Breeding Cycle of Wedge-tailed Shearwaters Puffinus pacificus at Heron Island, Great Barrier Reef

Heron Island (23\u2727\u27S, 151°55\u27E), is a small coral cay of the southern Great Barrier Reef, one of several cays constituting the Capricorn Group of islands which supports a large breeding colony of Wedge-tailed Shearwater Puffinus pacificus. These birds excavate burrows for nesting in suitable ground, and nest colonially (Warham 1990). To date, only breeding population estimates, burrow incubation rates, and a preliminary investigation into hatching success have been made at this locality (Gillham 1963; Shipway 1969; Ogden 1979, 1994; Hulsman 1984a; Hill & Barnes 1989; Dyer 1992; Dyer & Hill 1992; Ogden 1994; Hill et al. 1995). This study was based at Heron Island during the 1993-94 breeding season and describes the timing of the breeding cycle, particularly the hatching and fledging phases