It is a brood parasite, laying its eggs in the nests of other bird species and leaving them to raise its chicks.

Urodynamis taitensis is most closely related to the channel-billed cuckoo (Scythrops novaehollandiae), which lives in Australia, Papua New Guinea and Indonesia, according to Sorenson and Payne (2005).

A juvenile cuckoo is markedly different from the adult: it is spotted, with buff underneath and on the sides of the head and neck.

Supercilium, White's, bordered below by bold dark-brown eye stripe continuing downsides of neck, cheeks, chin, throat and foreneck, whites with thin brown stripes and fine black streaking on near neck and throat.

[2] Long-tailed cuckoo have a loud and intense sound, a "shrill whistle"; it is sometimes called the "screamer".

Long-tailed cuckoo prefer to live in forest on mainland and near shore or offshore islands, from sea level.

[6][7][8] Usually in dense, closed canopy of native forests dominated by beech Nothofagus, broadleaf species or podocarps or mixtures, with or without shrub layer.

They also live in exotic pine plantations, scrub, cultivated land and suburban gardens.

[13] The long-tailed cuckoo breeds only in New Zealand, where it is resident in the warmer months, from early October until February or March, sometimes April and occasionally later.

[16] The spread of its winter distribution is extraordinarily wide, stretching almost 11,000 km from Palau in the west to Pitcairn Island.

[17] In spring, the bird's routes of migration would almost certainly have served to guide the Polynesian ancestors of Māori to find New Zealand.

Males gain attraction from females through spanning their wings and fluttering them whilst calling.