Wallabies were introduced for sport and for the value of their skins. The four species established are the common scrub wallaby (Wallabia rufogrisea), black-tailed wallaby (W. bicolor), dama wallaby (Thylogale eugenii), and rock wallaby (Petrogale penicillata). Sir George Grey liberated the first wallabies on Kawau Island. They were later liberated on Rangitoto Island, near Rotorua, and in the Hunters Hills near Waimate. Wallabies still occupy areas near the points of liberation, but the common scrub wallaby has extended its range in South Canterbury. In 1940 it occupied some 100,000 acres, and by 1959 wallabies were reported on about 1,000,000 acres, including pastoral land where they were alleged to compete seriously for food with sheep. The spread in South Canterbury was perhaps accelerated by regular control – 5,000–6,000 wallabies were destroyed annually during the previous decade. Rabbit boards have recently assumed control of wallabies and by using 1080 (sodium fluoroacetate) poison have considerably reduced the numbers of wallabies in the Waimate and Rotorua districts.