The cuckoo is 37.5 cm (15 in) long, longer tailed than pied cuckoo, and with a more heavily streaked throat.
There are two colour morphs.
The light morph is black above, faintly glossed bluish or greenish.
The throat streaking may extend on to the sides.
The primaries and rectrix tips are white.
The dark morph is black except for the white primary patch and white spots on the outer tail feathers (these are absent in dark pied cuckoo.
The juvenile Levaillant's cuckoo is brown above, rufous on the wing-coverts and rectrix tips, with a buff forehead, face and underparts, and the throat more streaked.
 The call is a low ringing kuwu-weer, kuwu-weer... and an excited ku-wi-wi-wi.
The cuckoo is 37.5 cm (15 in) long, longer tailed than pied cuckoo, and with a more heavily streaked throat. There are two colour morphs. The light morph is black above, faintly glossed bluish or greenish. The throat streaking may extend on to the sides. The primaries and rectrix tips are white. The dark morph is black except for the white primary patch and white spots on the outer tail feathers (these are absent in dark pied cuckoo. The juvenile Levaillant's cuckoo is brown above, rufous on the wing-coverts and rectrix tips, with a buff forehead, face and underparts, and the throat more streaked.  The call is a low ringing kuwu-weer, kuwu-weer... and an excited ku-wi-wi-wi.
Levaillant's cuckoo