New Zealand Journal of Zoology abstracts
Determining burrow occupancy, fledging success and land-based threats to
mainland and near-shore island sooty shearwater (Puffinus griseus)
colonies
SHERYL HAMILTON
Department of Zoology
University of Otago
P. O. Box 56
Dunedin, New Zealand
Current address: P. O. Box 133, Leigh, Warkworth, New Zealand
Abstract A specialised infra-red camera "burrowscope" was
used to determine the burrow occupancy rate of sooty shearwaters at three
Nugget Point colonies, two Taiaroa Head colonies and one Tuhawaiki Island
colony in 1992/93, and the results compared to those given by less reliable
methods.
At three Nugget Point colonies, fledging success ranged from 0-41%. One of
these colonies also suffered high mortality of adults, most likely attributable
to mammalian predation, during the nest preparation and egg-laying period. At
the Taiaroa Head and Tuhawaiki Island colonies, low predator abundance may have
been an important factor contributing to the high fledging success (64-100%).
Several years of monitoring reproductive and survival parameters are needed to
verify the status of mainland colonies and the impacts of various possible
threats to their survival and productivity.
Keywords sooty shearwater; Puffinus griseus;
predation; burrow occupancy; methodology
Z97019
Received 30 May 1997; accepted 20 March 1998
PDF file of entire paper: medium quality (921K); (scanned from paper original: notes about this process)
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