2. NORTH ISLAND KAKA

The North Island kaka is a member of the Nestor parrot family. The other New Zealand members in this family are the South Island kaka and the kea.

Evolution It is thought that these birds had a common ancestor – the forest- dwelling proto-kaka that reached New Zealand between 10 and 5 million years ago.

A mountain-building phase started in New Zealand 5 million years ago. It was gradual at first, with the main thrust 2 to 3 million years ago. The Wendy Paul North and South Islands became separated 4 million years ago. The new species of kaka evolved as a result of the separation, the mountain- building and the Pleistocene Glaciation, which started 1.63 million years ago.

The proto-kaka of the South Island had to adapt to the increasingly colder climate and more mountainous country, which led to the gradual disappearance of forest. The new species that evolved was the kea, a mountain-dwelling parrot that survives on alpine plants, insects and dead animals.

As the ice sheets retreated 12,000 years ago, the South Island became forested again and some of the North Island kaka re-established populations in the South Island. Over time two sub-species evolved – the North Island kaka and the South Island kaka. Today Cook Strait now acts as a major barrier between the two populations.

Maori Maori named this playful and garrulous bird after its raucous screech – ka-a. They considered it the rangatira of the forest birds and valued it as food and for its feathers. Red feathers were particularly treasured and symbolised high rank when worn in cloaks. It was thought that flocks of kaka flew to Hawaiki and back to Aotearoa, the lead bird bringing back a stone which had powers. When a tohunga took this stone he had the powers passed on to him. For more information see: http://www.nzbirds.com.

Kaka facts The North Island kaka is slightly smaller and less colourful than the South Island kaka. The North Island female weighs about 425 grams and the male 475 grams - their length is 45cm. The kea is much the same size as the kaka but is almost twice the weight. The North Island kaka ranges from grey on the crest to olive-brown on the back with a reddish-brown

Bay of Plenty Supersites: 9 North Island Kaka at Whirinaki –Super Site Resource 1 underbelly and has a splash of bright orange-red under the wings. Sexes are alike but males have longer beaks. Its powerful hooked beak is used for tearing at bark and as a third leg when hopping and climbing. The clawed feet are used to hold food up to the mouth while eating and for grasping branches. It has a brush-tipped tongue that it uses to lick nectar and sap. The kaka lives for about 23 years, is gregarious, is not territorial and has the biggest vocabulary amongst the parrot world.

The kaka needs large tracts of forest and once existed in great numbers throughout the country. With destruction of the forest habitat, the North Island kaka is largely confined to Whirinaki and Pureora Forest Parks. However birds banded at Whirinaki have been found as far away as Gisborne. There are also smaller populations found in Tongariro and Urewera National Parks and in the Kaimanawa and Tararua Forest Parks. The Hen and Chicken, Great Barrier, Mayor, Kapiti and Little Barrier islands are also inhabited by these birds.

Podocarp forests are the primary habitat of the kaka in the North Island. There they feed on seeds, flowers, leaves and nectar. They strip the flesh from fruits like that found on the miro and eat the seeds. These seeds are extremely hard but the kaka breaks them open with its powerful beak. Grubs and insects they find under bark or in rotting logs are also favoured food items. Their beaks are used to strip away bark to expose and eat the underlying sap, from kamahi, totara, pohutukawa and Northern rata. This method of feeding leaves horizontal scars on the trunk or branches of trees. Honeydew excreted by scale insects living on the trunk or branches of beech trees makes up a small part of the North Island kaka’s diet.

Threats to the Kaka Declining numbers mean these birds are classified as threatened and are listed as nationally endangered species by DoC. http://www.kcc.org.nz/species/threatened/birds.htm. has more information. Apart from the destruction of their habitat, they suffer from competition with possums, rats and wasps and predation by stoats, ferrets, cats and rats. Possums live in the canopy eating flowers, leaves and fruit often destroying the plants that produce these. Rats eat seeds, reducing the regeneration of the forest and future food source. Wasps compete for the energy-rich honeydew and nectar - the introduced German wasp is a particularly strong competitor.

Competition reduces energy available to the kaka for breeding. Breeding occurs every four to five years producing two to six dull white eggs. The female incubates the eggs for about 28 -30 days, while the male brings food to her. Brooding continues for about 15 days and chicks stay in the nest for about 50 –70 days before they fledge and leave the nest unable to fly, spending the first week on the ground. The chick’s only defence is to stand still, making them particularly vulnerable to predators.

Kaka nest in hollows in trees, lined with wood they have chipped then chewed from inside the hollow. The eggs and fledglings are vulnerable to

Bay of Plenty Supersites: 10 North Island Kaka at Whirinaki –Super Site Resource 1 stoats, ferrets, possums, ship rats, and cats. Vulnerability of New Zealand birds arises from New Zealand being cut off from the rest of Gondwanaland 80 million years ago - due to seafloor spreading in the Tasman Sea. This meant that it was cut off from the mammals that evolved and spread throughout the rest of the world.

Apart from two species of bat, New Zealand’s birds developed without mammals so have not acquired defences against them, often living lifestyles which leave them open to predation by introduced mammals – in particular mustelids (stoats, ferrets) possums and cats. For more information on threats to kaka and the research being carried out, see: http://www.landcare.cri.nz/science/biodiversity/index.shtml?threats

Bay of Plenty Supersites: 11 North Island Kaka at Whirinaki –Super Site Resource 1