RELATIVE EFFECT OF CATS, MYXOMATOSIS, TRADITIONAL CONTROL, OR COMPETITORS IN REMOVING RABBITS FROM ISLANDS

The outcome of control on 607 islands of known area round the world was analysed to identify the most effective way of removing rabbits. More islands have been cleared of rabbits by traditional methods of trapping, shooting, and poisoning than by introduced predators, competitors, or disease, but their relative efficiency could not be calculated because unsuccessful attempts have not normally been recorded. Where hares were introduced, rabbits subsequently became extinct on 27% ot 105 islands; introduction of cats removed rabbits from 11% of 80 islands, myxomatosis from 10% of 119 islands; and cats and myxomatosis together from 3% of 40 islands. All these control techniques were more effective on smaller islands than on large ones. but rabbits have ''died out'' naturally on 11% of the 607 islands, and this factor is not linearly related to island area.