New Zealand Wattlebirds: Callaeidae
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
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.
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.
The Moa Pages. http://www.duke.edu/mrd6/moa (accessed on July 8, 2004).
Royal Forest and Bird Protection Society of New Zealand. http://www.forest-bird.org.nz (accessed on July 8, 2004).
Animal Life ResourceBirdsNew Zealand Wattlebirds: Callaeidae - Physical Characteristics, Behavior And Reproduction, New Zealand Wattlebirds And People, Conservation Status, Kokako (callaeas Cinerea): Species Account - GEOGRAPHIC RANGE, HABITAT, DIET