Bovidae

The breeding ranges of thar are described as they were in 1976 and 1984 and compared with previously described ranges in 1936, 1946, 1956 and 1966. Commercial hunting during 1972-1976 harvested about 32000 thar and along with habitat limits in some areas this slowed the rate of dispersal into new areas and eliminated thar from the periphery of their range in other areas. The rate of thar dispersal from the time of their liberation in 1904 until 1936 was non-linear and recalculation of their breeding ranges from 1936-1966 shows rates of dispersal consistent with an exponential curve.

Marked sites established around Port Ross in 1973 were re-examined in 1983 to measure changes in the vegetation and assess the impact of goats and pigs. Goats had not increased in numbers, nor extended beyond their earlier range, but they were seen higher on the Hooker Hills. Pigs were scarce, but their sign was seen throughout. Photopoints and numerical methods both showed that Chionochloa antarctica tussock was eliminated or greatly reduced where goats and pigs occurred together, and where only pigs were present it was reduced slightly.

Feral goats (Capra hircus) have been hunted intensively every year since 1972 on the 2950 ha Raoul Island to protect the indigenous vegetation. Rumen samples taken from 103 goats shot in 1982-83 showed that a minimum of 48 species of vascular plants, mostly indigenous species, were eaten. Only seven foods—Metrosideros kermadecensis, Coriaria arborea var. kermadecensis, Me/icytus ramiflorus spp. ramiflorus, Rhopalostylis baueri var.

Goats were liberated on Raoul Island early in the 19th century. Attempts to eliminate the goats commenced in 1937 and have accounted for at least 15 000 animals. Since 1972, when annual hunting expeditions began, both the number of goats and the area over which they range have steadily declined and the herd is now almost extinct. Despite these changes, the mean group size of goats in 1981-83 remained the same at 3.19, 2.74 and 3.24 respectively. On average, 19% of goats escaped each encounter with the hunters.

The diet of the North Island kokako (Callaeas cinerea wilsoni) was studied in three central North Island habitats, Pureora, Mapara, and Rotoehu, for three years. Possum (Trichosurus vulpecula) diet was less intensively studied for part of the same time in Pureora and Mapara. A literature review was made of the diet of possum, red deer (Cervus elaphus), and feral goat (Capra hircus). There is considerable overlap between the diets of kokako and the three mammalian browsers; leaves and/or fruit of some species are eaten by all four, e.g.