This EBA includes the North Island of New Zealand and its offshore islands, most notably Little Barrier and Kapiti, which are important refuges for many native birds. Mountain ranges extend in a line from Cook Strait to East Cape, with volcanic mountains being prominent landmarks, especially in the centre of the island where some are still active.

The characteristic vegetation is podocarp and mixed hardwood forest, with kauri Agathis australis often the dominant tree species in the warmer northern parts. The southern beech Nothofagus predominates in forest at higher altitudes, until true forest gives way to a narrow belt of subalpine forest, and ultimately to various scrub and shrubland communities, and tussock grassland.

The historical and current distributions of the restricted-range birds vary considerably. The main breeding population of Poliocephalus rufopectus is scattered in north Auckland, Rotorua and Taupo lake districts, Hawkes Bay and Wairarapa, and the west coast dune lakes. Coenocorypha aucklandica seems to have survived on Little Barrier Island until c.1870, and a form (known only from subfossils) was widespread on North Island but was probably rare or extinct by the time of Polynesian settlement. Mohoua albicilla formerly occurred throughout North Island but is restricted today to forests south of Te Aroha and East Cape, and to the offshore islands of Little Barrier, Kapiti and Tiritiri (where it is introduced). Notiomystis cincta was comparatively common in the south of North Island up to the 1870s but declined rapidly thereafter, and only survives on offshore islands including Little Barrier and (as a result of transfers) Hen, Kapiti and Tiritiri; also, following transfer, on Mokoia Island in Lake Rotorua. Heterolocha acutirostris was recorded historically from the forests of eastern and southern North Island, with the last generally accepted record in 1907.

An additional two restricted-range species occur in this EBA: Takahe Porphyrio mantelli, from South Island (EBA 207), has been introduced to the offshore islands of Kapiti, Tiritiri and Mana; and Wrybill Anarhynchus frontalis, also from South Island, winters in the north of North Island.

Four further species are largely confined to or have important breeding populations in this EBA, but are judged to have had historical ranges greater than 50,000 km² and are therefore not treated as having restricted ranges: Little Spotted Kiwi Apteryx owenii persists on Kapiti and has been introduced to the islands of Red Mercury, Hen and Tiritiri; Kakapo Strigops habroptilus has been introduced to Little Barrier; Kokako Calleas cinerea is sporadically distributed in the central and northern forests of North Island and introduced on the islands of Little Barrier and Kapiti; and Saddleback Philesturnus carunculatus survives as the result of introductions on some 10 offshore islands.

The forests of New Zealand, which once covered most of the islands, have been reduced by Polynesian and European settlers to less than 25% of their former extent, mostly in the mountains, and replaced by scrub, fernland, grassland, pasture and plantations of exotic softwoods. Wetlands have also diminished such that only c.8% of the original now remains (Davis et al. 1986, Jones et al. 1995c). This habitat destruction (and the resulting fragmentation), coupled with the introduction of a variety of mammals and European birds, has largely caused the extinction and decline in the ranges and numbers of many endemic birds (King 1984).

Two restricted-range species are classified as threatened: Poliocephalus rufopectus is considered to be at risk from changes in water quality, destruction of nesting habitat, disturbance, and (especially when nesting) predation by introduced rats and mustelids; Notiomystis cincta is thought to have been exterminated from the mainland as a result of predation, disease and collecting. Mohoua albicilla, however, remains relatively widespread and is not considered threatened, but has also declined, albeit slowly, being regarded as formerly abundant but now only moderately common.

There are many other threatened landbirds in this EBA, historically widespread, but many now with much reduced ranges, e.g. Brown Kiwi Apteryx australis (Vulnerable; the North Island race mantelli is treated as a full species by Baker et al. 1995), A. owenii (Vulnerable; see 'Restricted-range species', above), Australasian Bittern Botaurus poiciloptilus (Endangered), Blue Duck Hymenolaimus malacorhynchus (Vulnerable), Brown Teal Anas aucklandica (Vulnerable; the race chlorotis occurs on North Island and Great Barrier Island, and is treated as a full species by Marchant and Higgins 1990), Porphyrio mantelli (Endangered; see above), New Zealand Dotterel Charadrius obscurus (Endangered), Anarhynchus frontalis (Vulnerable; see above), Black Stilt Himantopus novaezelandiae (Critical; part of the population winters in the north of North Island), Strigops habroptilus (Extinct in the Wild; see above), New Zealand Kaka Nestor meridionalis (Vulnerable), Callaeas cinerea (Endangered; see above). Philesturnus carunculatus (see above) is classified as Conservation Dependent following successful reintroduction to offshore islands and an increasing population of over 2,000 birds.

Three threatened seabirds, all Vulnerable, are endemic breeders on offshore islands: Cook's Petrel Pterodroma cookii (also on Codfish Island off Stewart Island), Pycroft's Petrel P. pycrofti and Black Petrel Procellaria parkinsoni. Fairy Tern Sterna nereis, also Vulnerable but found elsewhere, breeds only on the northern coasts of North Island.

The New Zealand protected-area system is among the most comprehensive in the world, consisting of more than 2,000 individual areas and covering almost 20% of the total land area including many island refuges. However, many areas of native habitat on the mainland continue to be threatened: by the spread of the introduced Australian brush-tailed opossum Trichosurus vulpecula (a destructive herbivore, and recently shown to take eggs and chicks of Callaeas cinerea: D. Cunningham in litt. 1995), by increasing damage by feral goats and deer, by proliferation of exotic plants, and by the spread of wild conifers (IUCN 1992c); predation by introduced mammals also remains a major threat to many bird species. Much conservation effort has been concentrated on the restoration of offshore islands where predator eradication is feasible, and, increasingly, on the temporary control of predators on mainland habitat 'islands' (see, e.g., Ogden 1995).

Recommended citation
BirdLife International (2024) Endemic Bird Area factsheet: North Island of New Zealand. Downloaded from https://datazone.birdlife.org/eba/factsheet/206 on 23/11/2024.