Rhynochetos is a genus of ground-dwelling birds in the monotypic family Rhynochetidae. It contains two species, both endemic to New Caledonia, one of which is extinct.
Taxonomy
Rhynochetos jubatus is the only extant species of this genus and of the family Rhynochetidae. It is closely related to birds of the tropical Atlantic, Pacific and Indian oceans with its closest living relative being the sunbittern (Eurypyga helias). Currently there are two described species of Rhynochetos, however, it has been suggested that the extinct Rhynochetos orarius and the extant Rhynochetos jubatus are the same species.
Species
- Rhynochetos jubatus <small>Verreaux & Des Murs, 1860</small> – kagu
- †Rhynochetos orarius <small>Balouet & Olson, 1989</small> – lowland kagu
Description
Kagus are large, flightless birds described as something "between a small heron and a rail". Adults are about tall with uniform ash-grey plumage with distinct orange-red bills and legs. Characteristic of these birds are long crest feathers. They weigh between , with no significant size difference between males and females.
Herons can look anatomically similar but can be distinguished by the lack of bare red parts and uniform grey plumage.
The distribution of kagus over the island is very fragmented due to a very patchy forest cover. The forests lie of ultrabasic rocks, which tend to have less extensive forest cover. On these rocks, forests are restricted to higher altitudes and along water systems. Dry season fires also contribute to decreasing forest cover and thus further fragmentation of kagu populations.
Kagus raise on average about one hatchling yearly. The amount of breeding attempts of kagus are very variable, with any from 0-7 breeding attempts per year possible until a successful breeding attempt takes place. They will lay and incubate a single egg for about 5 weeks. At 3 days old, the parents will feed the chick during the day and brood at night. This will occur for 2 months, at the end of which the fledgling will be two thirds of its adult body size. The fledgling will typically be fed until it reaches 3.5 to 4 months of age.