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Black petrel survey 2001/02 (PDF, 360K)

Summary

During the 2001/02 breeding season for black petrel (Procellaria parkinsoni),285 burrows around the summit of Mt Hobson, Great Barrier Island, were identified and intensively monitored over summer. Only 283 burrows were included in the study and of these 192 were used by breeding pairs, 68 by non-breeding adults and the remaining 23 were empty. Several factors affecting black petrel breeding success were noted.

In April, 135 chicks were present in the study burrows, corresponding to a breeding success of 70%. Nine census grids were also monitored. A total of 125 burrows were located within the gridsand, of these, 81 burrows were used for breeding. An extra three burrows were found in three grids, two of which were newly dug and a previously investigated burrow was now active.

Extrapolating from these grid burrows we estimate that the black petrel population around the peak of Mt Hobson consists of 4000 birds. Nine chicks from earlier breeding seasons have been recovered within the Mt Hobson colony area. Of these, three have paired and successfully bred. A male pre-breeder (banded as a chick during the 1996/97 season) was caught on a longline vessel off the Kermadec Group. ‘Dummy’ satellite transmitters were placed on 24 adults, each incubating an egg. Only three transmitters were not recovered. One transmitter was seen by a Ministry of Fisheries observer near the West Norfolk Ridge (33° 54.6´ S, 167° 56´ E)