Mohoua is a small genus of three bird species endemic to New Zealand. The scientific name is taken from mohua – the Māori name for the yellowhead.[2] Their taxonomic placement has presented problems: They have typically been placed in the whistler family, Pachycephalidae, but in 2013 it was established that they are best placed in their own family, Mohouidae.[3] A large molecular genetic study published in 2019 found that the family is sister to the family Neosittidae containing the three sittellas.[4]
All three species display some degree of sexual dimorphism in terms of size, with the males being the larger of the two sexes.[5] Mohoua are gregarious (more so outside the breeding season) and usually forage in groups. They also forage in mixed species flocks at times, frequently forming the nucleus of such flocks.[2] Social organization and behaviour is well documented for all three Mohoua species; cooperative breeding has been observed in all three species and is common in the whitehead and yellowhead.[2] The three species of this genus are the sole hosts for the long-tailed cuckoo which acts as a brood parasite upon them, pushing their eggs out of the nest and laying a single one of its own in their place so that they take no part in incubation of their eggs or in raising their young.[5]
The genus Mohoua was introduced in 1837 by the French naturalist René Lessonto accommodate a single species, the yellowhead, which is therefore the type species of the genus.[6][7]