The New Zealand falcon or kārearea (Falco novaeseelandiae) is New Zealand's only endemic falcon and the only remaining bird of prey endemic to New Zealand. Other common names for the bird are bush hawk and sparrow hawk. It is frequently mistaken for the larger and more common swamp harrier
A member of the Falconidae bird family, the New Zealand falcon is mainly found in heavy bush and the steep high country in the South Island and is rarely seen north of a line through the central area of the North Island. A small population also breeds on the Auckland Islands; the species is known from the Chatham Islands from fossil remains. Although protected since 1970, it is considered to be a threatened species.[2]
Ornithologists variously described the New Zealand falcon as an aberrant hobby or as allied to three South American species (F. deiroleucus, F. rufigularis and F. femoralis); however studies of feather proteins suggest a close tie with the Australian brown falcon.[3]
It differs from the much larger swamp harrier (or kāhu), common throughout New Zealand, in that it catches other birds on the wing, and seldom eats carrion. An aggressive bird that displays great violence when defending its territory, the New Zealand falcon has been reported to attack dogs as well as people.
With a wingspan of about 45 cm (18 in) and weight rarely exceeding 450 grams (16 oz), the New Zealand falcon is slightly over half the size of the swamp harrier, which it usually attacks on sight. The male is about two thirds the weight of the female.[4]
The New Zealand falcon nests in a scrape in grassy soil or humus in various locations: under a rock on a steep slope or on a rock ledge, among epiphytic plants on a tree branch, or under a log or branch on the ground,[5][6] making the two or three eggs that they lay vulnerable to predators such as stray cats, stoats, weasels, possum, and wild dogs