The black petrel (Procellaria parkinsoni) is a vulnerable endemic seabird, which breeds only on Little and Great Barrier Islands, New Zealand. During late January and February 1997, within the main breeding area around the highest point on Great Barrier Island, Kirakimata (Mount Hobson), 100 burrows that had adults present were selected as long-term study burrows. The burrows were either accessible through the entrance or easily excavated to reach their contents. Eighty four of these burrows were used by breeding paris, and the remainder by non-breeding adults. The threee 1600 m2 census areas set up in 1996 around the summit were monitored over the 1997 breeding season. A total of 54 burrows were located within the census grids and 36 were being used by breeding pairs. A preliminary estiate extrapolating from the grid burrows shows the population consists of 4 500 breeding birds and at least 685 non-breeding birds.