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.