Medium-sized cuckoo - comparable in length to a medium-sized rock dove, but more graceful build. The total length reaches 32-34 cm, wingspan 55-65 cm, weight up to 80-190 g]. In an adult male, the entire upper side of the body, including the head, is colored dark gray. The throat and goiter are also gray, but of a lighter ash color. The belly is white, with dark transverse stripes. Tail feathers with white ends and spots along the stems. The plumage coloration of females is of two types, the so-called morphs or phases. The most common of these morphs repeats the details of the plumage of the male in such a way that it is very difficult to distinguish between individuals of different sexes in the field; a specialist can see a brownish tint on the back and sometimes sparse buffy feathers on the throat and crop. The second type of coloration, on the contrary, makes the female completely different from the male.
Representatives of this phase are rusty-red above and white below, with dark transverse striping on both sides. There are no streaks on the back only in the lumbar region, which is a distinctive feature of the red morph of the common cuckoo from a similar morph of the deaf cuckoo, common in Siberia and the Far East.
