Mortality factors acting on adult rabbits in central-western New South Wales

Abstract

Mortality of radio-tagged adult rabbits (Oryctolagus cuniculus) (n = 274) was monitored for one year in central-western New South Wales. The overall mortality rate was 82%. Predation was the most important and consistent cause of adult rabbit mortality, accounting for 44% of the total number of rabbits, followed by Rabbit Haemorrhagic Disease (RHD) (16%), myxomatosis (9%), unknown causes (9%), and enteritis/peritonitis (2%). Foxes were the most important predators, accounting for 28% of radio-tagged rabbits. Medium to large birds of prey were less important, accounting for 10%, followed by cats, which were responsible for 6% of the deaths of radio-collared rabbits. Myxomatosis outbreaks occurred in February/March and November–January. An RHD outbreak occurred during July, with 40% of the adult rabbit population being killed. The number of male and female radio-collared adult rabbits killed by each mortality agent throughout the year was similar. The proportions of warren-dwelling rabbits and surface-dwelling, solitary rabbits killed were similar overall; however, a significantly higher number of warren-dwelling rabbits were killed by myxomatosis and a significantly higher number of surface-dwelling rabbits were killed by RHD.