Eighteen sub-adult and five adult North Island Weka (Gallirallus australis greyi) were found dead on Kawau Island in the Hauraki Gulf, between 7 March and 20 April 1996. Weka initially collapsed losing leg control, and died within two days. All dead birds had ample fat reserves. No common cause of death was found in seven autopsies. No long term impact on the population is predicted.