Biology of the Wild Rabbit, Oryctolagus cuniculus (L.), in the Southern Tablelands of New South Wales

Abstract

Shot samples of rabbits were taken every eight weeks for two years at four sites in the Southern Tablelands of New South Wales. Age structure differed between sites. The two sites at which rabbits were controlled by poisoning had the youngest age structures; the site where rabbits were not controlled had the the oldest age structure, the lowest density, the least myxomatosis and the highest production of young per female. The seasonal percentages of males in the samples were inversely proportional to the percentages of lactating females. Rabbits that were recovering from myxomatosis had higher infestations of Graphidium strigosum than rabbits that had active myxomatosis or no symptoms. At one of the sites, rabbits with myxomatosis were shot on every sampling occasion. Differences between sites, in duration and timing of reproduction, were very small compared with differences between rabbit populations from climatically different regions of Australasia; annual production of young per female older than six months varied between sites from 23.7 to 26.5 compared with the range of 15-53 for Australasia. The percentage of pregnant females and fertile males was highest in late spring and fell to zero for 1-2 months in summer. This seasonal pattern of reproduction is intermediate between the pattern found in some high-rainfall Australasian environments, where more than 30% of the females are pregnant in all months, and the patterns in arid, semi-arid and subalpine environments, where no females are pregnant for 3-6 months of the year.