Control of bird-lime trees Pisonia umbellifera and pied currawongs Strepera graculina reduces mortality of Gould's petrel Pterodroma leucoptera nesting on Cabbage Tree Island, New South Wales, Australia
This study is summarised as evidence for the following.
Remove problematic vegetationAction Link
Control avian predators on islandsAction Link
Remove problematic vegetation
A before-and-after study on Cabbage Tree Island, south east Australia (Priddel & Carlile 1995) found that of 122 adult Gould’s petrels Pterodroma leucoptera leucoptera specimens in the Australian National Wildlife Collection, Canberra, 48% were thought to have been killed by becoming entangled in the fruits of the bird-lime tree Pisonia umbellifera. In addition, between 1989 and 1991, several petrels were seen entangled and dying in P. umbellifera fruits every year. However, following the eradication of most of the population of P. umbellifera trees in 1992 and their failure to flower in 1993, no petrels were found dead due to entanglement in the 1992-3 or 1993-4 breeding seasons. This study is also discussed in ‘Control avian predators on islands’.
Control avian predators on islands
A before-and-after study on Cabbage Tree Island, Australia, between 1992 and 1994 (Priddel & Carlile 1995) found that fewer Gould’s petrels Pterodroma leucoptera leucoptera were killed by pied currawongs Strepera graculina following intensive control at the start of the 1993-4 breeding season. Twenty petrels were killed by currawongs in October-November 1992 and 43 more were found (83% of all adult mortalities recorded) over the 1992-3 breeding season, despite the destruction of seven currawong nests. However, only four petrel mortalities (25% of the total) could be attributed to currawongs in 1993-4 following the killing of 22 currawongs, leaving a population of four to six individuals of which none bred. This study is also discussed in ‘Remove problematic vegetation’.