New Zealand Journal of Zoology abstracts
Dynamics of sparse rabbits (Oryctolagus cuniculus), Orongorongo
Valley, New Zealand
JOHN A. GIBB
3 Wairere Road
Lower Hutt, New Zealand
B. M. FITZGERALD*
Ecological Research Associates of NZ
P.O. Box 48-147
Silverstream, New Zealand
*Author for correspondence
Abstract The dynamics of a sparse population of rabbits on
100 ha of flats beside the Orongorongo River were studied for 21 years.
Distribution of rabbit sign and plant cover were measured annually over the
whole study area. The rabbits on 40 ha were counted monthly and
live-trapped for 10 years. The abundance of predators (cats and stoats) was
monitored by the frequency of sightings, and their diet from scats. Rabbits had
no warrens, but hid in the scrub by day and bred in stops. The amount of rabbit
sign was correlated with their numbers and food supply. Floods reduced plant
cover but opened new ground for palatable herbs. Without floods, shrubs
replaced herbs and rabbits decreased. Adult male rabbits were in good condition
and long lived. Adult females were in poor condition, produced rather few
young, and did not live as long as males. Many young died in the nest or were
killed by cats soon after they emerged. Cats also killed adult rabbits.
Population regulation probably involved both extrinsic and intrinsic factors:
predators and food shortage reduced the number of juveniles to a level at which
territoriality imposed effective control.
Keywords rabbit; Oryctolagus cuniculus; feral cat;
Felis catus; Orongorongo Valley; predation; population regulation
Z97022
Received 18 June 1997; accepted 23 February 1998
PDF file of entire paper: medium quality (1515K); (scanned from paper original: notes about this process)
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