Breeding and age structure of the population of Macropus parma on Kawau Island,New Zealand

The parma wallaby, Macropus parma, is one of four species of wallaby introduced on to Kawau Island, New Zealand, in ahout 1870. A sample of sixty-four parmas was shot on the island in February 1973 to provide information on breeding activity and age structure of the population. Incidental data were also collected from the tammar wallaby, Macropus eugenii, which is the other common species on the island. Neither the sex ratio of the shot sample of parmas (thirty-seven males to twenty-seven females) nor that of the tammars (eleven males to eleven females) differed significantly from parity. Onset of sexual maturity of female parmas on Kawau I. was delayed when compared with that of captive females. One female was estimated to have bred at 19 months old but most females in the sample were not mature until 2 years old and a few not until 3 years old. In contrast, female tammars became sexually mature at about 12 months. There did not appear to be any delay in the onset of sexual maturity of male parma wallabies. In the shot sample, none of sixteen female parmas capable of having a young were carrying a pouch young whereas nine of ten female tammars had a pouch young. The mean date of birth of these latter young was 30 January (range 18 January - 11 February) which is consistent with the breeding season of tammars in Australia. Among the mature female parmas two had recently mated, six were in pro-oestrus and six were in anoestrus, indicating that the breeding season in 1973 had just commenced. Estimated months of birth for all parmas under 3 years of age suggested that breeding was continuous in 1970–71 but that there had been a defined breeding season in 1972 with births occurring between March and July. There was an excess of 1– and 2–year-old parmas in the sample. This was the result of continuous breeding in 1970–71, presumably due to the provision of pasture on farmland being developed on the island. A sample of thirty-three tammar skulls resulting from a shoot in November 1972 did not show a nmilar excess of 1– and 2–year-old animals as this species has a rigidly defined breeding pattern and the females can produce only one young a year.