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An estimate of numbers of grey-faced petrels (Pterodroma macroptera gouldi) breeding on Moutohora (Whale Island), Bay of Plenty, New Zealand, during 1998-2000

  • Publication Type

    Journal Article

  • Publication Year

    2003

  • Author(s)

    M.J. Imber; M. Harrison; S.E. Wood; R.N. Cotter

  • Journal Name

    Notornis

  • Volume, Issue

    50, 1

  • Pagination

    23-26

  • Article Type

    Paper

  • DOI

    https://doi.org/10.63172/188053vlfzjn

Keywords

breeding population; estimate; grey-faced petrel; Moutohora; post-predation population recovery; Whale Island


An estimate of numbers of grey-faced petrels (Pterodroma macroptera gouldi) breeding on Moutohora (Whale Island), Bay of Plenty, New Zealand, during 1998-2000

Notornis, 50 (1), 23-26

M.J. Imber; M. Harrison; S.E. Wood; R.N. Cotter (2003)

Article Type: Paper

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Moutohora (Whale Island) holds the largest surveyed breeding colony of grey-faced petrels (Pterodroma macroptera gouldi). For our estimate of the breeding population, we divided the island into 16 sections within which burrow densities were approximately uniform; the surface areas of these sections were found by planimetry. Apparently completed burrows were counted in 1998-2000 within each section by plots of 2 m radius along linear transects, or by 10 X 10 m contiguous plots. The total estimate (± SE) for the island was 109,000 ± 10,000 burrows, which equates to about 95,000 pairs breeding annually, given an occupancy rate of about 87%. The population has apparently more than doubled since Norway rats (Rattus norvegicus) and rabbits (Oryctolagus cuniculus) were eradicated in 1985/87.