Australasian Harrier

Maori Name: Kahu

Circus approximans

Unlike many other species, the Australasian Harrier probably benefited from the European settlement and introduction of small mammals, especially rabbits, and birds which form the main part of their diet. 

Despite being persecuted in the 1930s and 1940s, Harriers have remained abundant.  Rabbit control has caused a slight decline in numbers but they remain common, and were protected in 1985.

Males establish their territories in May/June but the females only return in June-August.  From late July to October, on warm calm days, pairs can often be seen doing their spectacular ‘skydance’, accompanied by loud calls.  Nest building begins in Sept/October which the female makes as a low platform of bracken, manuka, raupo and flax stalks, topped with rushes, cabbage-tree leaves and grass.  The nests are built at ground level in swamps, rush-covered wetlands, young pine plantations, road verges or grain crops, and sometimes even on water up to 1.5 metres deep.  The female lays 2-3-5-7 eggs at 2-3 days intervals in Sept-Dec which she will incubate for 31-34 days.  During incubation the male feeds the female, passing food to her in the air which she will eat 20 to 100 metres away from the nest.  Sometimes the female may stop brooding, without discarding her young, as early as five days after the first hatching, so that the other eggs do not hatch.    The chicks fledge at 43-46 days old, in Dec-February, venturing further and further afield each day until finally dispersing about 7 weeks later.

Harriers are slim, medium-sized birds of prey, with hooked beaks and talons, long tails and broad wings. 

First winter Harriers have brown eyes, dark brown plumage with an obvious white nape patch.  Females change their eye colour to mid-brown in the second year and yellow in later years whereas males have yellow specks by 9 months of age and have golden-yellow eyes by the second year which in later years turn sulphur-yellow.  As the birds get older their plumage gets paler so that very old birds can appear almost grey.  Females are larger than males.

Australasian Harriers are found throughout NZ and the outlying islands.  They can also be found in southeastern New Guinea, Australia and Tasmania, New Caledonia, Fiji, Tonga and Vanuatu.

Australasian Harriers are widespread throughout the West Coast in open habitat and are commonly seen on or alongside roads, feeding on roadkill. Drivers need to be aware of this and slow down if a harrier is sighted on or near a road.