Survey and monitoring of black petrels on Great Barrier Island 2003/04

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Black petrel survey 2003/04 (PDF, 325K)

Summary

This report is part of an ongoing long-term study of the black petrel, Procellaria parkinsoni, on Great Barrier Island begun in the 1995/96 breeding season. During the 2003/04 breeding season, 327 burrows were checked and intensively monitored over summer; however only 324 burrows were included in the long-term study.

Of these study burrows, 208 were used by breeding pairs, 57 by non-breeding adults and the remaining 59 burrows were empty. By 10 May 2004, 108 chicks were still present in the study burrows and 50 others were presumed to have already fledged, corresponding to a breeding success of 76%.

Nine census grids were monitored within the study area and accounted for 134 of the inspected burrows, with 78 burrows being used for breeding. Two extra burrows were found in the grids, both of which were newly dug this season. Extrapolating from these grid burrows, we estimated that the black petrel population around the peak of Mount Hobson ranged from 2935 to 4690 birds.

There were 12 chicks from earlier breeding seasons recaptured within the Mount Hobson colony area this season. Of these, three paired and bred (one successfully). One chick (banded in 1998/99 season) was also recaptured off the coast of Peru, but this bird has not been recaptured at the Great Barrier colony yet. There were 13 adults colour marked (with fluorescent spray paint), but there were no reported sightings of these birds at sea.