Number, fate, and distribution of kakapo (Strigops habroptilus) found on Stewart Island, New Zealand, 1979–92

Abstract

This paper documents the number of kakapo (Strigops habroptilus) found dead or alive and their distribution on Stewart Island, New Zealand, between 1979 and 1992. In total, 91 birds were found, 85 alive (56 males and 29 females) and six dead. Of the 85 initially found alive, 61 (72%) were subsequently transferred to safe sites (Maud, Little Barrier, Codfish, and Mana Islands), 11 were not found again, and 13 were later found dead. Of those found dead, most had been killed or scavenged by feral cats. From a radio‐tagged sample of 13 adults, annual mortality in 1981–82 was estimated at 56%; after the instigation of a cat‐control programme in April 1981, mean annual mortality during 1982–89 was 2.4%. Most (76%) birds were located in a 4000 ha block about the southern end of the Tin Range. Similarly, 59% of 150 track‐and‐bowl systems found were within the same block of land. From the distribution of kakapo and of track‐and‐bowl systems in 1979–92, and the vulnerability of the species to predation by cats and rats, we conclude that the population had been in decline for some time.