The largest island population of North Island weka (Gallirallus australis greyi) in New Zealand, a Category B threatened species, is about 2100-5000 birds on Kawau Island in the Hauraki Gulf. Kawau I. is also inhabited by a number of pest mammal species, including four species of wallaby, believed to be a threat to the habitat of weka and other species. This report assesses the scientific evidence for wallabies as a key factor in affecting age-specific survival and/or fecundity of weka. It also examines other factors that could affect weka dynamics adversely. It was considered that North Island weka would benefit from wallaby removal, as would kiwi, through the regeneration of ground cover and ultimately the recovery of indigenous forest. However, wallaby eradication would not make weka immune from declines caused by combinations of disease, increased predation pressure, fire risk, and non-target kills from possum control operations, and it might involve some by-kill of weka from wallaby poisoning programmes. It is suggested that the Department of Conservation (DOC) should liaise with relevant Australian authorities to ensure, if warranted, that the four wallaby species are repatriated to Australia., where three of them are regarded as Near Threatened and one as Vulnerable. It is also suggested that DOC should work with an appropriate lead agency, such as the Auckland Regional Council to build on the wallaby control programme and community support already developed by the Pohutukawa Trust.
|Author||Shaw, W. G. and Pierce, R. J.|
|Secondary title||DOC Science Internal Series 54|
|Publisher||Department of Conservation|
|ISBN/ISSN||ISSN 1175–6519 / ISBN 0–478–22272–6|