Identification: Adult resembles Indian Cuckoo but has grey head, breast and upperparts, whitish underparts with prominent blackish bars and less obvious or no blackish bars on undertail. Hepatic female resembles hepatic female Plaintive and Rusty-breasted Cuckoo but has deeper orange upperparts and whiter underparts. It was formerly considered conspecific with Oriental Cuckoo (Cuculus optatus) which may occur in Singapore, but has no confirmed records. Based on current knowledge, it is impossible to separate Himalayan and Oriental Cuckoo without a recording of the vocalizations, or measurements of a bird in the hand.