Directions for future management of North Island Weka Gallirallus australis greyi to improve survival and productivity in situ

Abstract

We investigated how North Island Weka Gallirallus australis greyi could be conserved in situ at East Cape, New Zealand using banded and radiotransmitter-carrying Weka to measure home range size and use, reproduction and mortality. We fitted radiotransmitters to 28 Weka with 75% of the subsequent fixes from 18 birds being obtained at intervals of < 4 days. Home ranges of 10 males had an estimated median size of 10.6 ha, while 5 female home ranges had an estimated median size of 3.5 ha. Home ranges of individuals of both sexes overlapped. Within their home ranges, Weka preferred bush relative to pasture and may have preferred pines to pasture. Weka did not significantly prefer bush to pines. Breeding occurred year-round, with a summer peak, but 11 breeding pairs raised only four chicks to independence in two years. The causes of egg and chick mortality could not be established, but predators killed six adults, motor vehicles killed six and one adult died in a trap. Measurements of body size revealed that a male-biased sex ratio was likely (67:33). We concluded that the recovery of the North Island Weka population in the East Cape region will require improving reproductive success and decreasing predation on adults. We recommend that managers focus on predator removal and habitat creation in future.