Habitat factors affecting saddlebacks on Hen Island

[First paragraph...]
The North Island saddleback (Philesturnus carunculatus rufusater) was formerly widespread on the mainland and appears to have almost died out by 1875 (Buller 1888). It is now common only on Hen Island. A study was begun in 1963 by members of the Wildlife Branch, Department of Internal Affairs, the Ornithological Society of New Zealand and the Department of Scientific and Industrial Research, to help determine the factors influencing its numbers and survival on Hen Island. This paper is a preliminary report on habitat based on observations made during August 1963, January 1964 and May 1965.