The body length is approximately 28cm. Head and neck dark ash and the underside with a lot of horizontal stripes on a white background. At first glance, look like small pieces of thin, but the beak bent down for a little longer, but did not burn like a hawker. They have two legs and each of it has two toe. Appearances is similar to a cuckoo but they are much smaller and bottom of the body has the horizontal pattern with a width 2 ~ 3mm than Cuckoo’s. The female is simmilar to male but sometimes dark brown with horizontal patterns among them.
They live Korea, Ussuri, China and the Himalayas, Japan, and Taiwan, and India in winter. In summer, It is common in South Korea, so you could hear all day in summer. They crying while sitting in a tree and flying. Usually It’s hard to see them because they hide in the middle height of the tree but it can be seen flying in the sky . They cry all day and night. lay their eggs Northern Bush Warbler and crowned willow Warder’s nest. After hatching, the little cuckoo pull out of nest and grow up in that nest.