Kahu (Swamp Harrier)
The swamp harrier is a large, tawny-brown bird of prey that occurs throughout New Zealand. It is an opportunistic hunter that searches for food by slowly quartering the ground with its large wings held in a distinctive shallow V-shape. Adapted to hunt in open habitats, its numbers have benefitted from widespread forest clearance and the development of agriculture. Although carrion is a major component of the harrier’s diet, it also actively hunts live prey such as small birds, mammals and insects. Capable dispersers, birds from New Zealand visit islands as far north as the Kermadec Islands and as far south as Campbell Island. Known for their dramatic ‘sky-dancing’ courtship display the swamp harrier is the largest of the 16 species of harriers found worldwide.
It is not unusual to see harriers soaring over Tiritiri Matangi in search of prey. They have large territorial ranges and frequently visit from the mainland. They have been known to take brown teal/pateke and kokako. Harriers only take prey that is on the ground, on a pond or in a tree, so a bird’s best way of escaping a harrier’s talons is to take flight. Flocks of birds have been observed mobbing harriers as they hunt and occasionally are successful in chasing them out of an area.