Birds of New Zealand, Hawaii, Central and West Pacific

South Island is dominated by a row of Alps over the full western length. The subduction processes in the trenches north and south of South Island are contrary to each other, pressing the alpine area together. Along the main Alpine Fault both ‘Alp-halves’ are sliding along each other (the western ‘half’ moving faster north). Secondary faults are forming the highlands near Kaikoura. This is also the place where the deep Kermadec Trench brings cold, fish-rich water near the coast, attracting a host of seabirds.

North Island is dominated by volcanic activity. The Pacific Plate dives under the Australian Plate that carries the island. Where the plate sinks into the liquid-hot asthenosphere, magma is released and ‘floats’ to the surface forming an arc of volcanoes in the Taupo Volcanic Zone. In this zone and elsewhere there are several lakes in places where once large to very large magma chambers exploded (each one forming a ‘caldera’), after which the remains collapsed and were filled by rain water. It is also the zone where many hot springs are found; the water that surfaces here (often as steam) is heated deeper down in the earth’s crust. The volcanoes and calderas outside the Taupo Volcanic zone are mainly remnants of older volcanic arcs.

LAND USE AND VEGETATION TYPES Originally the greater part of New Zealand was covered by forest. After the arrival of the Polynesians (ad1000) and later on the settlement of the Europeans (from about ad1840) more than 50% of the forest was cleared, mainly by fire and grazing. Origin-ally there were no mammals in New Zealand except seals and three bat species, but when the first people arrived they introduced unwillingly or with full intent a wide range of animals, which started to compete with or to live on the native flora and fauna, driving many endemics to complete or near-extinction. The most dangerous intruders were black rats, mice, feral cats and possums. The latter not only eat eggs and nestlings of indigenous species but also the saplings and fresh shoots of indigenous trees and plants. The best places to see remaining endemics are a few islands and a single mainland sanctuary that have been made predator-free.

Before the arrival of the Europeans there were very few deciduous tree species, the 13m-high Tree Fuchsia (Fuchsia excorticata) among them.

The main habitats include the following:

Farmland, orchards, high producing grassland: together covering about 24% of the total land area.

Extensive grasslands: low vegetation, mainly with exotic and indigenous grasses. Livestock tend to be grazed over large areas. Some extensive grassland may have conservation or recreational uses.

Mosaic of different types of forest and farmland: among these is coastal forest, which is not very tall and is made up of plants that can tolerate salty winds. It generally lacks large conifers and has fewer vines and epiphytes. The canopy is dense and wind-shorn.

Lowland forest: resembles tropical rainforest, but is less rich in species. Found mainly in the northern half of North Island. A typical species is Kauri, a gigantic conifer with small oval leaves. Further south other tall species such as Southern Beech dominate. In most places all or most tall trees have been felled.

Upland forest: dominated by Southern Beech. Undergrowth less dense than in lowland forest. Before the introduction of possum, deer and goat, was rich in berry-producing shrubs.

Planted forest: mainly pine species, but also eucalyptus. Often with rich undergrowth of native plants. Covers about 7% of total land area.

Lakes: the lakes of South Island are drowned glacier valleys, those of North Island are mainly water-filled calderas (collapsed magma chambers).

Note: most natural inland wetlands of New Zealand have been drained for agriculture.

The Birds

Island Avifauna

The area covered by this book is characterised by its immense water surface, its countless small islands and the often enormous distances between them. This makes the avifauna typically island in character.

Of the 125, worldwide recognised true seabirds (albatross and petrels), 87 (or 70%) occur in the area.

As a result of the islands never having been connected to other land masses, the birds that are present have arrived on their own wings or with sea currents, by evolution or by human introduction (Polynesians and Europeans). About 70 species (9%) have been introduced, at least 201 species (25%) are endemic, so about 510 species came unsupported from elsewhere.

Before the arrival of humans there were no mammals in the area, except seals, bats and fruit-bats. There were not many birds of prey either. Many bird species could therefore afford to lose the ability to fly; 12 flightless species (excluding penguins) can still be found, namely five kiwis (all species), three rails (Weka, Takaha and Henderson Island Crake), three ducks (Auckland Duck, Auckland Teal and Campbell Teal) and one parrot (Kakapo).

The arrival of man with his domesticated animals and stowaways, such as black rats and the wilful introduction of predators such as weasels and stoats (as means to control other introduced animals such as rabbits), meant the extinction of many species. Fairly recently it appeared that avian diseases spread by mosquitoes have been responsible for the extinction and near-extinction of several species on the Hawaiian Islands (e.g. the Hawaiian Crow). In the mid 1960s the Brown Tree Snake sneaked into Guam. Without the natural predators of the snake or adequate defence by the autochthonic birds the Guam Flycatcher was extirpated and the Guam Rail could only survive in captivity.

An appendix to this book presents a list of 59 species that have become extinct since 1800.

The islands’ isolation has also had these effects:

• many species are fearless and docile. Indigenous birds in New Zealand, for instance, are often easily approachable;

• the genus Acrocephalus spread over many islands and split up in 12 endemic species; these differ mainly in the degree of leucism. The Tahiti species occurs also as a rare melanistic morph;

• islands tend to produce dwarf (none in the area) or giant species. The giants are extinct (unless one wants to consider Takahe, the world’s largest rail and Kakapo, the world’s heaviest parrot, as such). Extinct are the ten ostrich-like, forest dwelling Mao species in New Zealand (the largest reached a length of 2.7m). They were preyed upon by the likewise extinct Haast’s Eagle, which, with a length of 1.7m, was the largest raptor that lived in historical times. Other giants – likewise extinct – were Moa-nalos (giant ducks from Hawaii), Vitilevu Giant Pigeon and Eyles’s Harrier from New Zealand;

• a large amount of endemics. An endemic is a species that occurs only in an area with well-defined boundaries, such as a continent, a country, an island or a habitat. In this book 201 species are mentioned as endemic; only those, occurring with their full life-cycle solely in one of the 20 countries of the area, are treated as endemics, but does not include those restricted to, for example, a group of countries or the whole area. Subspecies are incidentally mentioned as endemic in the captions.

The Endemic Species of the Area

The following pages show maps and the endemics as thumbnails (not depicted to relative scale), arranged per country. The numbers preceding the species refer to the plates and numbers of the species on the plates, while the numbers at the end of the entries refer to the islands on the maps of the countries where the species occur.

Hawaii Endemics

304 species, including the following 33 endemics:

11.6 (#litres_trial_promo) Hawaiian Petrel Breeds Ha 1,2,4,?5,?7

Pterodroma sandwichensis

24.6 (#litres_trial_promo) Hawaiian Goose Ha 1,2,5,7

Branta sandvicensis

27.2 (#litres_trial_promo) Hawaiian Duck Ha 1,2,6,7,8

Anas wyvilliana

27.4 (#litres_trial_promo) Laysan Duck Ha 13,17

Anas laysanensis

32.6 (#litres_trial_promo) Hawaiian Hawk Ha 1

Buteo solitarius

38.7 (#litres_trial_promo) Hawaiian Coot Ha 1–7

Fulica alai

74.1 (#litres_trial_promo) Omao Ha 1

Myadestes obscurus

74.2 (#litres_trial_promo) Kamao ?Ha 7

Myadestes myadestinus

74.3 (#litres_trial_promo) Puaiohi Ha 7

Myadestes palmeri

74.4 (#litres_trial_promo) Olomao Ha ?5 (no records since 1980)

Myadestes lanaiensis