The effects of artificial control on the feral cat Felis catus Linnaeus population on Marion Island

Abstract

Hunting was used as one method in a long-term campaign to eradicate feral cats on sub-Antarctic Marion Island. A total of 872 cats were shot during 14 725 man-hours over four years. Accurate estimation of cat numbers was not possible, but cats sighted per hour of night hunting was a reliable index of density. Hunting resulted in a marked decrease in density, but became ineffective at low densities and gin trapping was incorporated into the programme. Eighty cats were trapped. Fecundity decreased with the decrease in cat density. Birds decreased significantly in the diet of cats, ascribed to decreased availability as a result of cat predation. Chicks formed a substantial proportion of birds taken. Breeding success of two burrowing petrel species increased with the decrease in cat numbers. Hunting successfully removed large numbers of cats and recovery of bird populations appears likely. The prospects of eradicating the cats are good.