Kahu - Australasian harrier - Circus approximans
Photographed soaring over the wetlands at Lake Ellesmere.
Harrier hawk or swamp harrier. A bird of the open country. It is often seen soaring and looking for prey, or eating dead rabbits or possums on the road. Also occurs in Australia, New Guinea and many islands of the southern Pacific. In New Zealand it is found from the Kermadec Islands in the far north, to the chilly subantarctic islands and the Chatham Islands.
Fossil records show that it came across the Tasman Sea from Australia, and became established in New Zealand less than 1000 years ago. At that time Eyles’s harrier (Circus eylesi), four times larger, was also present.
At 850 grams, fully grown females are 200 grams heavier than males. Both sexes are the same length, about 55 centimetres. The oldest known age for a harrier in New Zealand is 18 years.
Australasian harriers hunt in open country. After Europeans arrived in New Zealand and cleared land for farming, the birds’ numbers increased. They catch small birds and mammals up to the size of rabbits, as well as lizards, frogs, fish and large insects. They also eat carrion, including road kill and dead lambs. Since the 1950s, successful rabbit control has meant less food for harriers, and their numbers have fallen.
The harrier is an adept hunter when flying, as ornithologist Edgar F. Stead observed:
One day I watched a Harrier beating over a stubble field, when it flushed a Skylark, which flew away some distance and settled. The Harrier carefully marked the spot, and flew swift and low towards it; saw the Lark, and struck at it on the ground. The Lark dodged the blow, ducked out from beneath the Hawk, and settled again about two yards away; but the Hawk, with a rapidity of movement with which one could scarcely have credited it, rose and swept back on its victim and flew off with it in its talons.
I had a similar experience just recently, when driving past a field of winter brassica of some sort near Hakatere Conservation Park (an area known for its harriers and the native falcon (Falco novaeseelandiae). The brassica was mobbed with vast numbers of finches (I couldn’t work out what sort). Several harrier were hawking over the field driving the birds to ground where they were plunged upon. Of course some of the birds were scared into flight in dense mobs and I was amazed to see a very rare native falcon streak in at very high speed and take a bird mid-air from a mob, clearly taking advantage of the confusion and panic created by the slower flying harriers.
When looking for food, harriers hold their large straight wings in a shallow V to soar on thermal winds, circling effortlessly until they dive for prey. In their courtship ritual, the male performs steep dives and loops, and the female turns on her back in mid-air to greet him.
The breeding season starts in June, when males establish territories of several square kilometres. Females build nests in tall grass-like plants such as toetoe. They usually lay three to five off-white eggs between September and December. The male does not feed the chicks, but delivers food to his mate while both are flying. Chicks are able to leave the nest at 45 days.
Māori knew older harriers as kāhu-kōrako, a reference to their pale feathers. As harriers grow older, they lose the dark plumage of youth, and some very old birds appear almost grey.
To Māori, the harrier was a symbol of victory and chieftainship.
Kahu - Australasian harrier - Circus approximans
Photographed soaring over the wetlands at Lake Ellesmere.
Harrier hawk or swamp harrier. A bird of the open country. It is often seen soaring and looking for prey, or eating dead rabbits or possums on the road. Also occurs in Australia, New Guinea and many islands of the southern Pacific. In New Zealand it is found from the Kermadec Islands in the far north, to the chilly subantarctic islands and the Chatham Islands.
Fossil records show that it came across the Tasman Sea from Australia, and became established in New Zealand less than 1000 years ago. At that time Eyles’s harrier (Circus eylesi), four times larger, was also present.
At 850 grams, fully grown females are 200 grams heavier than males. Both sexes are the same length, about 55 centimetres. The oldest known age for a harrier in New Zealand is 18 years.
Australasian harriers hunt in open country. After Europeans arrived in New Zealand and cleared land for farming, the birds’ numbers increased. They catch small birds and mammals up to the size of rabbits, as well as lizards, frogs, fish and large insects. They also eat carrion, including road kill and dead lambs. Since the 1950s, successful rabbit control has meant less food for harriers, and their numbers have fallen.
The harrier is an adept hunter when flying, as ornithologist Edgar F. Stead observed:
One day I watched a Harrier beating over a stubble field, when it flushed a Skylark, which flew away some distance and settled. The Harrier carefully marked the spot, and flew swift and low towards it; saw the Lark, and struck at it on the ground. The Lark dodged the blow, ducked out from beneath the Hawk, and settled again about two yards away; but the Hawk, with a rapidity of movement with which one could scarcely have credited it, rose and swept back on its victim and flew off with it in its talons.
I had a similar experience just recently, when driving past a field of winter brassica of some sort near Hakatere Conservation Park (an area known for its harriers and the native falcon (Falco novaeseelandiae). The brassica was mobbed with vast numbers of finches (I couldn’t work out what sort). Several harrier were hawking over the field driving the birds to ground where they were plunged upon. Of course some of the birds were scared into flight in dense mobs and I was amazed to see a very rare native falcon streak in at very high speed and take a bird mid-air from a mob, clearly taking advantage of the confusion and panic created by the slower flying harriers.
When looking for food, harriers hold their large straight wings in a shallow V to soar on thermal winds, circling effortlessly until they dive for prey. In their courtship ritual, the male performs steep dives and loops, and the female turns on her back in mid-air to greet him.
The breeding season starts in June, when males establish territories of several square kilometres. Females build nests in tall grass-like plants such as toetoe. They usually lay three to five off-white eggs between September and December. The male does not feed the chicks, but delivers food to his mate while both are flying. Chicks are able to leave the nest at 45 days.
Māori knew older harriers as kāhu-kōrako, a reference to their pale feathers. As harriers grow older, they lose the dark plumage of youth, and some very old birds appear almost grey.
To Māori, the harrier was a symbol of victory and chieftainship.