Control of feral cats on sub-Antarctic Marion Island, Indian Ocean

Since their introduction in 1949, feral cats have caused extensive damage to seabird populations on sub-Antarctic Marion Island, Indian Ocean. This paper reports on the first four years of an eradication programme launced in 1986. Eight hundred and seventy-two cats were shot dead and 80 trapped during 14 725 hours of hunting. Cats sighted per hour of night hunting and kills per hour decreased dramatically. Hunting success (cats killed as a proportion of those seen) decreased. The only reliable indication of the decrease in density as a result of hunting was the decrease in the number of cats seen per hour of night hunting. By the end of the third season it was apparent that hunting alone was no longer removing sufficient animals to maintain the population decline, and trapping was incorporated into the eradication programme.