North Island Brown Kiwi (Apteryx mantelli)

North Island Brown Kiwi

[order] APTERYGIFORMES | [family] Apterygidae | [latin] Apteryx mantelli | [UK] North Island Brown Kiwi | [FR] Faucon emerillon | [DE] | [ES] Kiwi de Mantell | [NL] Kiwi

Subspecies

Monotypic species

Physical charateristics

Medium-sized kiwi, flightless, no visible wings. Dark greyish-brown feathers streaked lengthways with reddish-brown. Long ivory bill. Similar spp. Okarito birds distinguished from Tokoeka A. australis by slightly greyer plumage, occasional white facial whiskers.

wingspan min.: 0 cm wingspan max.: 0 cm
size min.: 38 cm size max.: 40 cm
incubation min.: 70 days incubation max.: 80 days
fledging min.: 7 days fledging max.: 8 days
broods: 1   eggs min.: 1  
      eggs max.: 1  

Range

Australasia : New Zealand. Apteryx mantelli was once widespread throughout the North and northern South Islands of New Zealand.

Habitat

These kiwis are found from sea level to 1,200 meters. Their original habitat was moist coniferous forest dominated by kauri and tree-ferns. Clearing of much of this primeval forest has forced many kiwis to attempt to survive in partially timbered agricultural areas. The largest remaining population of Brown Kiwis on North Island resides in a large commercial pine plantation.

Reproduction

Kiwis form life-long pair bonds and exhibit remarkable fidelity to their home territories. They will remain in a territory for weeks after every tree has been logged. Territories range in size from 5 to 50 hectares depending on the quality of the habitat. Kiwis excavate several burrows within each territory. A typical underground burrow has one entrance, a tunnel 20 to 200 cm in length and a terminal chamber large enough to accomodate both birds. They will also utilize hollow logs or shallow holes dug out between tree roots. Kiwi nests are usually located in well established burrows where the surrounding foliage has had time to grow up and thoroughly conceal the entrance. The female Brown Kiwi lays 1 or 1 glossy white eggs of prodigious size, 14-20 percent of her body weight. Producing such a large and energy rich (more than 60 percent yolk) egg depletes the females energy reserves. There is a period of 25 to 30 days between the laying of the first and second egg. It is entirely understandable that she leaves the male alone in the nest burrow to handle the 70- to 80-day incubation by himself.

Kiwi chicks have no egg tooth and must use their feet to kick their way out of the shell. A newly hatched kiwi looks like a mini replica of the adult, at 1/8 adult size. They are precocial chicks, able to forage for themselves with only minimal paternal supervision for their first few days of life. Although completely independent by two weeks of age, they do no reach adult size until they are 18 to 20 months old.

Feeding habits

Brown kiwis have an extremely varied diet which includes earthworms, beetles, snails, crayfish, insects, fruits, and berries. The unique bill is used to sniff out food as the bird forages by plunging it repeatedly into the leaf litter of the forest floor in search of prey. They forage actively from dusk to dawn.

Conservation

Mainland populations of this species may be decreasing by as much as 86% in three generations (36 years), based on annual declines, predation and loss of habitat. However, owing to the stability of island populations, and intensive predator control in select mainland populations, the overall decline is likely to be less than 80%, thus warranting Endangered status.
Kiwis have long been the cherished national mascot of New Zealand. Though they have enjoyed complete legal protection since 1896 and large tracts of pristine forests have been set aside in parks and reserves, their numbers are dropping by 5.8 perecnt each year. In 1996 scientists estimated the brown kiwi population at 35,000 birds. They predict that if current trends continue that number will drop to 20,000 by the year 2006. Kiwi populations have been on this downward slide ever since humans arrived in New Zealand more than a thousand years ago.
North Island Brown Kiwi status Endangered

Migration

Sedentary

Distribution map

North Island Brown Kiwi distribution range map

Leave a Reply

Your email address will not be published. Required fields are marked *