An adult kagu is about the size of a domestic chicken, with a head-and-body length of about 22 inches (55 centimeters), and a weight of 1.5 to 2.5 pounds (24 to 40 ounces). A kagu resembles a small crane with a coat of very light gray feathers, a short tail, and reddish-orange beak, eyes, legs, and feet. A crest of feathers crowns the kagu’s head. When not raised for display, the crest lays down towards the back of the head.
The beak is long and slender. The edges of the nostrils are raised into ringlike flanges, making the nostrils look like short tubes. The flanges keep soil from getting into the nostrils as the bird forages in leaf litter and soil for food. The scientific name of the bird, Rhynochetos jubatus, from the Latin, translates as “tube-nosed, head-crested.”
The wings are light gray with black, dark, lighter gray, and brownish spots arranged in rows or bars along the outer sides of the open wings. The dark spots are covered when the wings are closed. Although the wings are large and look flightworthy, kagus cannot fly, since they have lost most of the mass of their once-powerful flight muscles. The open wingspan can reach 32 inches (80 centimeters).
Although most bird species that spend time on forest floors are camouflaged (KAM-uh-flajd), the adult kagu doesn’t follow that rule, being light-colored and very obvious in a dark forest. It may be that kagus never needed camouflage before people brought dogs, cats, and other predators, animals that hunt them for food, to Grand Terre. Or, the light coats may have evolved for a territorial role, enabling kagus to easily spot other kagus, during mating times or for defending territories. Kagus are always ready to chase off other kagus that intrude on individual territories. Kagu chicks are brown and light brown colored, which does help them to blend into the colors of the forest floor.
Grand Terre, the largest island of the New Caledonia island group, in the southwestern Pacific Ocean. Presently, the entire population of kagus is broken up into isolated groups in various forest areas on Grande Terre. The largest population lives in Blue River Territorial Park, near the southern tip of the island. The park is patrolled and dogs are kept at bay. The second largest population is legally protected in Nodela Special Reserve, but the reserve has no guards or controls on dogs. There is a third small, partly fenced park for semi-captive breeding of kagus, near Noumea, the capital of New Caledonia.
Kagus live in most kinds of forest on Grand Terre, although they seem to prefer tropical rainforests, from sea level up to 4,200 feet (1,400 meters). They will forage in shrubby or bushy areas and in low-growing dry forest, during the seasonal rains, when their sort of animal food becomes abundant. Kagus do not inhabit grasslands.
The kagu eats ground-living snails, insects, spiders, earthworms and lizards, which it forages for on forest floors. The most popular foods among kagus are earthworms and snails. Since the abundance and types of food creatures change with the seasons, and to keep from eating too much food in one area, kagus forage in different parts of their territories at different times of the year.
A kagu begins a feeding run in the early morning by simply standing still. With its excellent vision and hearing, the kagu is listening for the faintest noises and looking for the slightest movements that may betray the presence of food animals. After picking out certain spots that harbor food creatures, the kagu walks slowly and starts probing the layer of dead leaves on the forest floor at those spots.
When a kagu spots a prey animal, the bird approaches it carefully, then lunges at it and snags it in a quick motion. Kagus hunt not only in the layer of fallen leaves on the forest floor for spiders, beetles and snails, but pokes its beak into the soil to expose worms and larvae. It deals with snails by smashing the shell on a rock to get at the snail’s body.
BEHAVIOR AND REPRODUCTION
Kagus are active during the day and sleep at night. A kagu sleeps out the night at one of several sleeping stations in its territory, rotating its overnights at the various stations over time. Most of the time, a kagu climbs a tree to perch for the night on a branch 5 to 12 feet (1.5 to 3.7 meters) above the ground. In high, mountainous territory with cool nights, a kagu prefers nighttime shelter in enclosures formed by rocks or in tree roots.
Kagu male and female pairs mate for life. Mated pairs stake out large forest floor territories, through which the birds wander daily, searching for food. Outside of the breeding season, the male and female stay in their territory but temporarily split up and wander alone.
Kagus make dog-like barkings, hissings, and rattling noises. Every morning, shortly before dawn, kagu pairs sound off with barkings, the male and female taking turns. A threatened kagu warns with a hissing sound.
The breeding season runs from June to December, the most breeding taking place in July. During those months, unmated kagus display for mates by raising the head crest into a magnificent plume and spreading their wings out as wide as possible and tipping them up and forwards so that the outer wing surface faces forward, showing the dark markings. Both sexes display. A female will answer a displaying male with a similar display. Then they perform a courtship dance, circling each other. The dance may end with mating, or the pair may lose interest and stop the dance, each bird going its separate way. Kagus of both sexes also display to defend territory.
A mated kagu pair builds a ground nest of dry leaves, eight to twelve inches in diameter, in which the female lays a single egg weighing two and a half ounces. The male and female take turns sitting on the egg for twenty-four hour stretches, one parent usually replacing the other at midday. The incubation period lasts an average of thirty-five days. The young chick has a coat of brown, downy feathers. Both parents care for the chick, and feed it with insects, spiders, and earthworms.
At only three days of age, the chick will begin walking away from the nest. At first, it doesn’t wander very far, but by the end of its first week, it has hiked up to 450 feet (137 meters) from the nest. After about six weeks, the young bird begins roosting overnight on low-placed tree branches, as its parents do.
Should a chick die before it matures, the female will soon lay a second fertilized egg as a replacement. The parents stop feeding the young when they are three and a half to four months old, forcing the young to strike out on their own for feeding. Nevertheless, the young may stay with their parents indefinitely, even when mature, and assist the parents in caring for younger brothers and sisters. This is a very rare behavior among birds, but routine in some mammal species like the small, New World monkeys known as marmosets and tamarins.
Kagus in captivity can live up to thirty years. Those in the wild generally live fifteen years.
KAGUS AND PEOPLE
Like many island bird species, the ancestors of the kagus lost their powers of flight and became ground-living animals. With no predators to fear and plenty of food on the forest floors, kagus had no need of flight and the enormous amounts of energy that flying requires. So the ancestral kagus gave up flying, keeping large wings for display purposes. They were safe on the ground and must have been quite numerous, even into the hundreds of thousands, until the arrival of humans on the islands.
Kagu species, living and extinct, were hunted for food and for ornamental feathers by the native people of New Caledonia, and this most likely pushed the extinct kagu out of existence. European settlers captured kagus for keeping as pets or for use of their feathers as decorative hat plumes, which were popular in the early 1900s.
Other major, human-made threats to kagus include loss of habitat and fragmentation of populations. Forests are being cleared for agriculture and especially for mining, since Grand Terre has some of the world’s most abundant supplies of nickel ore. Once free to roam all over the island, the original population of kagus is split up and isolated into small pockets throughout Grand Terre. This is not good for breeding, since there is no free exchange of genes across a large population, which is the healthy state of things in a wild species.
The kagu is listed as Endangered, facing a very high risk of extinction, under the U.S. Endangered Species Act and on the Red List of the World Conservation Union (IUCN).
The rehabilitation of the kagu is one of conservation’s better success stories, although the birds are still listed as Endangered. That kagus still survive and have even increased their numbers since 1980 is largely due to the efforts of one man, Yves Letocart, a New Caledonian citizen, who has been working with kagus and their environment since 1980. Much of what we know about kagu behavior comes from Letocart’s field work.
Today, as a result of Letocart’s field work, captive breeding and release of young birds, and predator control, an estimated 300 kagus inhabit Blue River Park, which has been classified and proclaimed a territorial park by the governments of New Caledonia and France. The kagu is now the official emblem of New Caledonia.
Most important for the survival of the kagu is protecting it in areas made inaccessible to invasive animals by trapping, shooting, and the use of fencing; increasing the kagu’s numbers through captive breeding; and creating forest “corridors” that allow isolated populations to intermingle.