Kagu close relationship between the kagu and sunbittern. The kagu and sunbittern, and possibly the adzebills, seem to form a distinct Gondwanan lineage of birds, possibly one order, possibly more, though the relationships between them and groups previously considered related, such as the mesites and the "core Gruiformes," are not yet resolved. It is notable, however, that the sunbittern and the mesites possess powder down too, whereas the "core Gruiformes" do not. While the kagu is the only living species in the clade Rhynochetidae, a larger species, the lowland kagu ("Rhynochetos orarius"), has been described from Holocene subfossil remains. The measurements
Kagu crest and wings are used in territorial displays towards other kagu, slightly different displays are used towards potential predators. Territorial disputes may be resolved by fighting using wings and bills, in the wild this seldom results in serious injuries. The kagu is exclusively carnivorous, feeding on a variety of animals with annelid worms, snails and lizards being amongst the most important prey items. Also taken are larvae, spiders, centipedes and insects such as grasshoppers, bugs, and beetles. The majority of the diet is obtained from the leaf litter or soil, with other prey items found in vegetation, old logs and