The Plaintive Cuckoo is a small cuckoo with a gray head and breast and reddish underparts. It uses habitats from forest to parks, and brood parasitism on Ashy Tailorbirds is recorded in Singapore.
Adults have a gray eye-ring, head, throat, and upper breast, with peachy-rufous underparts below. Some females have a hepatic form resembling a juvenile. Juveniles have paler rufous to whitish underparts with fine dark barring.
It occurs in forests, forest edges, mangroves, parks, and gardens. In Singapore, it is a known brood parasite of Ashy Tailorbirds.
An extinction-risk assessment has not been added yet.