Norfolk Island, an Australian external territory, is an isolated, volcanic outcrop (reaching 318 m at Mt Bates) between New Caledonia (EBA 201) and the North Island of New Zealand (EBA 206), some 1,300 km east of mainland Australia. Two other islands, Nepean and the larger Philip Island, complete the Norfolk Island group.

Norfolk Island was originally largely covered in thick subtropical rain forest including pine forest dominated by the endemic Norfolk Island pine Araucaria heterophylla, mixed hardwood forest, palm and tree-fern forest.

All the extant restricted-range birds occur in forest, with Gerygone modesta and Zosterops tenuirostris adapting well to secondary habitats (see Schodde et al. 1983, Hermes 1985). Norfolk Island has lost three of its restricted-range species: one still occurs elsewhere, but two are globally extinct. An additional extinct species, Norfolk Island Ground-dove Gallicolumba norfolciensis, not recorded since 1800, is known only from a drawing and written observations.

Several endemic subspecies also occur or occurred on Norfolk Island, and two seabirds with tiny breeding ranges nest on nearby Philip Island (see 'Threats and conservation', below).

Forest on Norfolk Island has been greatly reduced by clearance for agriculture and settlement, and has been disturbed by timber exploitation, uncontrolled cattle-grazing and the introduction of a wide range of exotic plant species (many of which have become invasive, e.g. red guava Psidium guajava and lantana Lantana camara which supplant native species beneath forest canopies).

Native vegetation now exists only in limited areas around Mts Pitt and Bates, and other pockets are so small and isolated as to be almost inconsequential (Schodde et al. 1983, WWF/IUCN 1994-1995).

One species largely confined to forest, namely Zosterops albogularis, is consequently considered highly threatened. Predation by black rats is also a serious threat to this species, compounded by predation by feral cats and competition from the Silvereye Z. lateralis which colonized the island at the beginning of the twentieth century; the last confirmed record of Z. albogularis was in 1980 although local people consistently report small numbers of birds fitting its description and it is therefore not treated as extinct (Garnett 1993). Both Gerygone modesta and Z. tenuirostris are classified as threatened, despite being common, on account of their tiny ranges, which render them forever vulnerable to chance events.

Several endemic subspecies of birds are listed as threatened or extinct by Garnett (1993), also largely owing to habitat loss and degradation, and the effects of introduced species: New Zealand Pigeon Hemiphaga novaeseelandiae spadicea (last recorded in 1900, and treated as extinct), Norfolk Island Boobook Ninox novaeseelandiae undulata (a sole surviving female in 1986, but see Olsen 1996), Norfolk Island Parakeet Cyanoramphus novaezelandiae cookii (treated as a full species by Sibley and Monroe 1990; c.40 birds in 1991) Scarlet Robin Petroica multicolor multicolor, Golden Whistler Pachycephala pectoralis xanthoprocta and Grey-headed Blackbird Turdus poliocephalus poliocephalus (last seen in 1975 and thought to be probably extinct).

A seabird with a very restricted breeding range (otherwise known to breed only on Lord Howe Island, EBA 204), Providence Petrel Pterodroma solandri, was exterminated from Norfolk Island between 1790 and 1800 by hunting and by the effects of introduced pests such as pigs and goats (Marchant and Higgins 1990), but small colonies have recently been reported from Philip Island, as have colonies of White-necked Petrel P. cervicalis—which is known to breed elsewhere only on Macauley Island (2 km²) in the Kermadec Islands of New Zealand. Both species are considered threatened (Vulnerable) on account of their tiny breeding ranges.

The declaration in 1986 of the Norfolk Island National Park (formerly the Mount Pitt Reserve), which encompasses the main remaining stands of native forest (4.6 km²), may ensure the long-term survival of the surviving endemic landbirds, especially as steps are being taken to reduce rat and cat predation within the park (Brouwer and Garnett 1990).

Recommended citation
BirdLife International (2024) Endemic Bird Area factsheet: Norfolk Island. Downloaded from https://datazone.birdlife.org/eba/factsheet/204 on 23/11/2024.