Kagu are territorial, maintaining year-round territories of around . They have a clan-based social organization, with families composed of one breeding female and one to three breeding males. Male offspring also help to defend their parents' territorial claims. However the social organisation of kagu has been disrupted in recent years due to attacks by dogs and families. Cases where either the breeding male or female have been killed have led to non-fraternal polyandrous behaviour. Cooperative and unrelated polyandry is rare in birds, but has been seen in species such as the Dunnock and the Tasmanian nativehen.
