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Studies of the rabbit population on Macquarie Island.

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Skira, Irynej Joseph (1979) Studies of the rabbit population on Macquarie Island. Research Master thesis, University of Tasmania.

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Abstract

Studies were made of the ecology of rabbits on Macquarie Island, the
predation on rabbits by skuas and the distribution and extent of spread
of the European rabbit flea. The numbe:r of rabbits on Macquarie Island estimated from visual counts
was in the order of 50 OOO. Most rabbits were present on 35% of the
island, of which 7% had >15 rabbits per 2 ha. 'I'he ma.in coat colours were agouti (83%) and black (17%). The rabbits moulted twice a year. Females were heavier than males during the
summer when breeding occurred, while males were heavier during winter.
The mean weight of liver, kidneys and spleen in female rabbits was
greatest in the summer and adrenal glands were heaviest in the winter.
In male rabbits the kidneys and spleen were heaviest in the smamer,
the liver and adrenal glands heaviest in winter.
The breeding season extended from late August 1974 to mid-March 1975 Skua territories were widely distributed on the island but no pairs that
nested in the bleak upland regions searched,reared chicks. Eighty
pairs formed territories in the areas of > 15 rabbits per 2 ha compared
with 30 pairs in areas with 6-15 rabbits per 2 ha. Predation on rabbits
increased only during the first month of the skua chicks growth thereafter
remaining constant with 98% of rabbits taken under 0. 74 kg.
Only 28% of all the rabbits sampled carried European rabbit fleas.
Infestation levels fell when rabbits were not breeding and did not
increase until two months after rabbits began to breed again. Dispersal
of fleas from areas where they were released was very slow.
In the one hundred years that the rabbit has been on Macquarie Island
it has adapted to the environment until it is now found in many localities
where suitable habitat is present, and its numbers vary locally in
abundance from sparse to numerous.
and both sexes showed an annual cycle in development and regression of
the gonads. Sixty-four per cent of natality occurred by mid-December;
female rabbits in their first year of breeding bearing the greatest
number of kittens.
The sex ratio of male to female was 1:0.84. Adult rabbits predominated
in the population in the 1973-74 summer while in the 1974-75 summer the
population was composed equally of adults and rabbits 12 months old or
less. Mortality occurred mainly amongst rabbits less than 4 months
old and was considered to be mainly due to effects of wet burrows and
predation by feral cats and skuas.

Item Type: Thesis (Research Master)
Keywords: Rabbits, Rabbits, Rabbits
Copyright Holders: The Author
Copyright Information:

Copyright 1979 the Author - The University is continuing to endeavour to trace the copyright
owner(s) and in the meantime this item has been reproduced here in good faith. We
would be pleased to hear from the copyright owner(s).

Additional Information:

Thesis (M.Sc.)--University of Tasmania, 1979. Bibliography: l. 162-171

Date Deposited: 03 Feb 2015 03:22
Last Modified: 11 Mar 2016 05:56
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