Thursday, December 2, 2021

Monitoring grey-faced petrels (Pterodroma macroptera gouldi) in a restoration project on Motuora Island, Hauraki Gulf

TitleMonitoring grey-faced petrels (Pterodroma macroptera gouldi) in a restoration project on Motuora Island, Hauraki Gulf
Publication TypeJournal Article
Year of Publication2008
AuthorsGardner-Gee, R, Rayner, M, Beggs, JR
Type of Articlearticle
KeywordsGrey-faced Petrel, Motuora, Pterodroma macroptera, restoration, seabirds

Motuora is a highly modified island in the Hauraki Gulf that is currently being re-vegetated. It is envisaged that the island will eventually be restored to a native forest system with strong seabird influences. The island retains a small breeding population of grey-faced petrels (Pterodroma macroptera gouldi). In 2005 a survey of the accessible areas of the coastal margin was carried out to estimate the current size of the population. The survey located 406 active burrows and it was estimated that approximately 260-280 burrows contained incubating pairs. There was some evidence that active burrow numbers had increased at established breeding areas since the last survey in 1995, but differences between survey methods made comparisons difficult. Fixed monitoring plots were put in place in 2005 to provide a standardized measure of changes in burrow activity. Between 2005 and 2007 no change in the number of active burrows was discernible in the fixed plots. Longer term monitoring will be required to determine the population dynamics of the Motuora grey-faced petrels as evidence from other locations indicates that growth (if it occurs) will be slow. Consequently, seabird numbers (and associated nutrient inputs) on Motuora are likely to be below pre-disturbance levels for many decades. These results highlight the challenges of ecosystem restoration in highly modified habitats.

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