Recolonisation by Rabbits (Oryctolagus Cuniculus) After Warren Ripping or Warren Fumigation.

Abstract

Attempts were made to exterminate rabbits at six separate sites; recolonisation was measured over the following two years. Three sites were treated by repeated warren ripping and three by repeated warren fumigation. At all sites the warren treatments were supplemented by shooting and dogging. Two years after treatment, the density of rabbits was 56% of the original density on fumigated sites and 50% on ripped sites. In the first year after treatment, reopened warrens were found more commonly than newly dug warrens; in the second year there were more new warrens than reopened ones. More of the treated warrens reopened on fumigated sites (40%) than on ripped sites (21%). For individual warrens, the number of entrances at treatment and the distance a warren was from untreated rabbit populations were the main factors influencing the probability of reopening. Population density on the periphery of the sites was the main factor influencing the rate of recolonisation of the sites and group control schemes are recommended to minimise recolonisation after control.