THE ECOLOGY OF THE EUROPEAN RABBIT (ORYCTOLAGUS-CUNICULUS) IN COASTALSOUTHERN WESTERN-AUSTRALIA

Demographic changes in three free-ranging rabbit (Oryctolagus cuniculu s) populations were monitored over 4 years in southern Western Austral ia. Peak densities followed periods of high rainfall and pasture bioma ss. The breeding season was prolonged, often extending from at least A pril to November, with some pregnancies occurring outside this period. Fecundity, determined by the autopsy of pregnant offsite rabbits and the known length of each breeding season, appeared to be relatively hi gh, with the potential for 34-39 kittens doe(-1) year(-1); however, be cause not all females are pregnant in all months, the overall producti vity of these populations was estimated at 25-30 kittens adult female( -1) year(-1). Exponential rates of increase varied from 0.13 to 0.30 d uring the breeding periods and -0.05 to -0.14 during the nonbreeding s eason. Kitten survival was generally low whereas some adults lived for more than 5 years. Two patterns of myxomatosis were observed: annual epizootics of the disease (3 of 4 years) and an epidemic that slowly s pread over many months. European rabbit fleas were most abundant durin g winter-spring and attained highest densities on adult female rabbits .