T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network


Kiwi (North Island brown kiwi) Apteryx mantelli

Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Apterygiformes
Family: Apterygidae
Genus: Apteryx
Species: A. mantelli,
Binomial name: Apteryx mantelli
Synonyms: Apteryx australis, Apteryx bulleri both still used in some sources
Common name: North Island brown kiwi

Apteryx mantelli is a species of kiwi that is widespread in the northern two-thirds of the North Island of New Zealand and with about 35,000 remaining. It is the most common kiwi and is found throughout the North Island, occurring near Northland, Coromandel, Eastern North Island, Aroha Island, Little Barrier Island, Kawau Island, Ponui Island, and the Whanganui Region. The North Island brown kiwi has demonstrated a remarkable resilience: it has adapted to live on scrub-like farmland, pine plantations, and their native forests, but it still prefers dense, sub-tropical and temperate forest. Apteryx mantelli are unique as their own type (or taxon) of the brown kiwi species. They have their own genetic makeup, behaviour and ecology and are slightly larger and heavier than the three other brown kiwi taxa.

Females stand about 40 cm high and weigh about 2.8 kg the males about 2.2 kg. The females have bills ranging from 117 mm to 156 mm long, while male bills range from 86 mm to 119 mm. The plumage is streaky red-brown and spiky. The North Island brown kiwi is the only species of kiwi found internationally in zoos and it has the world record for laying the largest eggs relative to its body size.

This kiwi, like all kiwi, feeds on grubs and other small insects that are found underground. They occasionally eat berries from native plants. A kiwi digs into the ground with its sharp talons then shoves its long beak down the soft ground. The kiwi’s eyesight is very poor so the parts of it brain that is devoted to smell and touch are large. This keen sense of smell and its long beak helps the kiwi to locate food beneath the soil and leaf litter. The kiwi is the only bird in the world with external nostrils at the tip of its long beak.  Kiwi sometimes sounds like pigs, snuffling and snorting loudly to clear dirt from their nostrils.

Apteryx mantelli usually pairs bond for life, with males generally preparing the nest and incubating eggs. The nest is a burrow or depression under tree roots or a hollow log. They typically lay eggs in June and July, with a second clutch laid from October to December with usually 2 eggs in each clutch. 
Chicks are fully feathered at hatching and leave the nest and can fend for themselves within 1 week. They can breed successfully at just one-year-old, although three to five years is more common.

The North Island brown kiwi is endangered, per the IUCN Red List with the major threat coming from predators, such as dogs, cats, and the stoat (Mustela erminea). 94% of chicks die before breeding in areas where mammalian pest control is not carried out. It has an occurrence range of 38,400 km2 with a population, estimated in 2000, of 35,000. Kiwi can't fly; they have an under-developed wing and chest muscles and lack a sternum (breastbone) so their rib cage is very vulnerable. This makes them particularly vulnerable to crushing injuries, such as those caused by dog bites.

Saving Northland's kiwi from dogs factsheet (PDF, 600K) 

Nationwide studies show that on average only 5 percent of kiwi chicks survive to adulthood. However, in areas under active pest management, survival rates for North Island brown kiwi can be far higher. For example, prior to a joint 1080 poison operation undertaken by DOC and the Animal Health Board in Tongariro Forest in 2006, 32 kiwi chicks were radio-tagged. 57% of the radio-tagged chicks survived to adulthood. Thanks to ongoing pest control, the adult kiwi population at Tongariro has almost doubled since 1998.

To hear the calls of the kiwi visit: https://www.kiwisforkiwi.org/about-kiwi/kiwi-facts-characteristics/kiwi-calls/      

A male Northern Brown Kiwi (Apteryx mantelli). 
Photo courtesy of Maungatautari Ecological Island Trust http://www.maungatrust.org/ Photo by Kahuroa, Wikipedia photo.

Apteryx mantelli strong legs and powerful claws used to dig in the forest floor searching for food.


A chick breaking out of its egg.
 

The areas of New Zealand where the kiwi species are located.
  

Thanks to Wikipedia for text and information     https://creativecommons.org/licenses/by-sa/3.0/