New Zealand Wattlebirds: Callaeidae

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NEW ZEALAND WATTLEBIRDS: Callaeidae

KOKAKO (Callaeas cinerea): SPECIES ACCOUNT

PHYSICAL CHARACTERISTICS

The New Zealand wattlebirds' common name is based on their "wattles," little, drooping flaps of brightly colored skin that decorate their faces just behind the beaks, in pairs, on either side of the throat. Plumage (feathers) in adult wattlebirds is medium blue-gray in the kokako and near-black with red-brown areas in the saddleback. Both sexes within a species have similar colorings, and all species have brightly colored wattles. The wings are short and rounded, and all species are poor flyers, able only to glide downward from a perch, although all can run, hop and jump along the ground or tree branches and all are good tree climbers. Adult length in both sexes, from beak tip to tail tip, runs 10 to 19 inches (25 to 48 centimeters). Weight is 2.5 to 10 ounces (70 to 380 grams).

GEOGRAPHIC RANGE

Wattlebirds live on both main islands (North and South Islands) of New Zealand and many offshore islands. Wattlebirds are New Zealand endemics, meaning that they are found only there and nowhere else in the world.

HABITAT

Wattlebirds inhabit native temperate forests of New Zealand, which are made up of a mix of hardwoods and podocarps (Southern Hemisphere conifers).

DIET

Wattlebirds eat mostly insects, including insect larvae (LAR-vee), wetas (giant New Zealand crickets), fruits of native trees, fern fronds, and leaves. On Cuvier Island, a small bird, the fantail, has taken to following foraging saddlebacks, snagging various flying insects escaping from the disturbances made by the saddlebacks. Since the saddlebacks eat noisily while producing a small rain of shredded bark and leaves, and occasionally call out during feeding, they are easy to find.

BEHAVIOR AND REPRODUCTION

Wattlebirds spend their days foraging mainly for insect food in forest trees and in the leaf litter on forest floors. They are poor fliers but quick, efficient ground runners and tree climbers. Since they had little to fear in the way of ground predators before the arrival of humankind, flight became less of a necessity for the wattlebirds' ancestors in New Zealand, so that they were freed from having to consume the enormous amounts of energy needed for flying.

Saddlebacks breed from October into January. The female builds a nest of twigs and grasses in a rock crevice or a hollow in a tree, then lays two light gray or whitish eggs, which the female incubates for twenty days. The male feeds the female while she is nesting, and both parents feed the chicks. The chicks fledge at twenty-one days of age. Kokako pairs breed from November through February and raise up to three clutches of chicks over the course of one year.

Wattlebirds sing to attract mates and establish and keep territory. Their singing has been described as similar to organ music, haunting, melodious, and complex.

WETAS: BIG, FAT CRICKETS

Among the more exotic food items that New Zealand wattlebirds prey upon is a sort of creature as unique to New Zealand as the wattlebirds. They are wetas, giant crickets that can grow larger than mice. Most weta species are omnivorous, just as are most mice species, eating mostly plant material with some insect prey, but a few species have become more or less completely carnivorous. They are no sort of threat to human beings.

NEW ZEALAND WATTLEBIRDS AND PEOPLE

One species, the huia, went extinct, died out, in the early twentieth century. Maori chiefs and nobles wore huia feathers as symbols of office and kept them in specially carved boxes. These same feathers eventually became fashionable as hat decorations in Europe. Traders offered bounties to native people to hunt, kill, and bring back huia feathers for export. The last sighting of huias is generally listed as having been in 1907, but William Cobeldick, a forest ranger, claimed to have spotted a huia pair in Urewera National Park in 1924.

CONSERVATION STATUS

The huia and the South Island subspecies of kokako are extinct. The North Island subspecies of the kokako and the saddleback looked likely to follow until work on the part of the government of New Zealand brought about an increase in their populations since the 1960s. According to the World Conservation Union (IUCN), the kokako is listed as Endangered, facing a very high risk of extinction, and the saddleback is Near Threatened, in danger of becoming threatened with extinction.

Once inhabiting large stretches of forest on the mainlands and some islands, saddlebacks are no longer found on the mainland. Of the South Island subspecies, only 650 individuals were still alive in the early 1960s, and confined to Big South Cape, Pukeweka, and Solomon Islands. The North Island subspecies lived only on Hen Island.

In 1964, the New Zealand Wildlife Service (NZWS) captured a number of North Island saddlebacks on Hen Island, then released them on nearby Whatapuke Island, where any introduced predators had been exterminated. The new colony proved successful. Rats had gained a foothold on Big South Cape Island, so, during the same year, the NZWS transferred thirty-six saddlebacks from Big South Cape Island to other, pest-free islands. That modest number has since increased its population to over 700. The North Island saddleback now inhabits nine large islands. The South Island saddleback lives on eleven smaller islands.

KOKAKO (Callaeas cinerea): SPECIES ACCOUNT

Physical characteristics: Also commonly called the blue wattled crow, the cinerous wattled bird, and the organbird, the kokako still hangs on in the face of habitat loss and introduced predators. There are two subspecies, populations, the North Island kokako and the South Island kokako. The South Island kokako has not been seen since 1967 and is presumed to be extinct.

The adult head-and-body length of the kokako is 15 inches (38 centimeters) and the adult weight is around 8 ounces (230 grams). The body and head plumage is medium blue-gray, and a black bandit-mask marking surrounds the eyes. The beak and legs are black. The North Island subspecies has blue wattles, while the wattles of the South Island subspecies were orange. The young have pink wattles that assume their proper hues by the time they fledge.

Geographic range: Kokakos live on North Island, New Zealand.

Habitat: These birds are found in native temperate forests of New Zealand, made up of a mix of hardwoods and podocarps (Southern Hemisphere conifers).

Diet: Food eaten in the wild includes fruits, insects and other invertebrates, animals without a backbone, buds, flowers, and nectar. Food choices and amounts consumed vary according to season. Fruit makes up about half the amount of food consumed during three-fourths of the year.

Behavior and reproduction: Kokakos forage during the day among forest trees from the highest reaches to about 9 feet (2.7 meters) from the ground.

Single kokakos and kokako male and female mated pairs begin their territorial songs at dawn, from treetops and tops of ridges. After fanning wings and tail, they warm up with some preliminary buzzing and meowing sounds, then explode into fantastically complex organ-like music. Soon, other kokakos answer, their music partly repeating that of the first singers but with some improvisations of their own. People privileged to hear this rare natural music have often described it in almost supernatural terms as an unforgettable experience.

Kokako pairs breed from November through February, although in years of unusual food abundance that period may begin in October and extend until May. Pairs have been known to raise up to three clutches of chicks in a year's time. The female does most of the nest building, in a tree, up to 100 feet (30 meters) above the ground. The male helps by occasionally bringing in building materials. The nest is well hidden and complex. The female begins with a twig framework, over which she builds a main mass of intertwined moss, lichen, ferns, and orchids, finally ending the construction by lining the bowl with tree fern scales. The female lays up to three pinkish gray eggs, which hatch after an incubation period of eighteen days. The chicks take thirty to forty-five days to fledge, grow their flying feathers, but may remain in the nest, still being fed by the parents, for up to a year. Only the female incubates eggs and cares for the young, although the male feeds the female while she is incubating and feeds the chicks.

Because of the long time spent in the nest by kokako mothers and chicks, they are particularly vulnerable to being killed by introduced mammalian predators. By 1990, at least two-thirds of the population of kokako females had been killed, leaving a surplus of males.

Kokako males sometimes form pairs with other males and a pair will go on and build nests. This behavior may have arisen recently, since throughout the last century, males far outnumbered females, many of which were killed while brooding, and the frustrated male mating urge found this new outlet.

Individual kokakos have been known to live up to twenty years.

Kokakos and people: In addition to being well known for their singing, kokakos are a symbol for conservation in New Zealand and even appear on some of their paper currency. Feathers of the kokako were used to adorn certain Maori garments. In Maori myth, a kokako aided the warrior Maui by transporting water to him in its wattles.

Conservation status: In 1990, the total population of kokakos on North Island was estimated at 1,160, of which only 396 were females, scattered about the island in isolated populations. Through an intensive program of breeding and habitat protection and regeneration, New Zealand's Department of Conservation has enabled the species to increase its numbers and recolonize abandoned habitat on North Island. By 2003, the population had added about 500 individuals. Thriving colonies have also been established on several satellite islands. ∎

FOR MORE INFORMATION

Books:

Birdlife International. Threatened Birds of the World. Barcelona and Cambridge, U.K.: Lynx Edicions, 2000.

Field, L. H., ed. The Biology of Wetas, King Crickets, and Their Allies. Wallingford, U.K.: CABI Publishing, 2001.

Heather, Barrie, and Hugh Robertson. Field Guide to the Birds of New Zealand, rev ed. New York: Oxford University Press, 2001.

Moon, Geoff. Photographic Guide to the Birds of New Zealand. London: New Holland Publishers, 2002.

Phillipps, W. J. The Book of the Huia. Christchurch, New Zealand: Whitcombe & Tombs, 1963.

Periodicals:

Hooson, S., and G. Jamieson. "Variation in Breeding Success Among Reintroduced Island Populations of South Island Saddlebacks, Philesturnus carunculatus carunculatus." Ibis 146, no. 3 (July 2004): 417.

McLean, Ian G. "Feeding Association Between Fantails and Saddlebacks." Journal of Ecology 7 (1984): 165–168.