Kagu or scratch away debris. Kagus are monogamous breeders, generally forming long-term pair bonds that are maintained for many years, even possibly life. Kagu can be long lived, with birds in captivity living for over 20 years. A single nesting attempt is made each year, although should the first nesting attempt fail a second attempt is made that year. A simple nest is constructed, which is little more than a heaped pile of leaves, although in some cases the egg may be laid directly on the ground. The nest is not concealed but is usually adjacent to a tree trunk, log
Kagu some range contraction due to hunting and predation by introduced species. Its original, pre-human distribution, and the extent to which it and its sister species "R. orarius" coexisted in lowland areas of New Caledonia, is still not fully understood and awaits further research into the subfossil record. Kagu are territorial, maintaining year-round territories of around 10–28 hectares (22–62 acres). Within the territory the pairs are solitary during the non-breeding season, and may have separate but overlapping foraging areas. Kagus make a range of different sounds, most commonly while duetting in the morning, each duet lasting about 15 minutes. The kagu's