Sulphur–crested cockatoos arrived in New Zealand as caged birds from Australia. Since about 1920 some have escaped and others have been released. Possibly this feral population is occasionally boosted with wind–blown stragglers from Australia. Such a bird may have arrived in May 1959 when after three days of strong westerlies a sulphur–crested cockatoo was seen at the southern head of Kaipara Harbour, so tired it would fly only downwind. In New Zealand the species’ largest colonies are in the watersheds of the Turakina and Rangitikei Rivers near Wanganui, where a population of about 400 birds was estimated in 1962, and also between the lower Waikato and Raglan Rivers where a flock of about 200 birds was seen in 1964.
Little is known about its breeding habits in New Zealand. At Hunterville in January birds were seen entering and leaving a nest hole high up in a kahikatea tree. Presumably the cockatoos were incubating eggs or else brooding young nestlings. Another nest was found on top of a pile of hay bales under the roof of a barn. In Australia, the nest is usually in a hollow limb or hole high up in a large tree. It also nests in cliff holes. On a layer of decayed wood–dust lining the bottom of the hole, the female lays two or three white, elliptical eggs. Both sexes incubate the eggs which hatch after about 30 days. The nestlings leave the nest at about 40 days old.
When giving his courtship display, the male struts along a branch towards the female. With crest raised he bobs and sways his head in a figure–of–eight movement, calling soft, chattering notes. Mutual preening and bill–touching follow.
The Sulphur–crested Cockatoo’s normal diet consists of berries, seeds, nuts and roots. It also takes handouts from humans. The species has become a pest around urban areas, where it uses its powerful bill to destroy timber decking and panelling on houses. Feeding normally takes place in small to large groups, with one or more members of the group watching for danger from a nearby perch.
