The Common moorhen is a medium sized bird, measuring 30-38cm in length. It appears mostly black from a distance, with a noticeable red shield on the forehead, a yellow tipped red bill and white lines along the sides. The tail of the bird is black with a slight green shine and has white feathers underneath, while the head and neck are dark grey. There is an olive-brown tinge at the back of the neck and rest of its body is a mix of olive brown and olive green with yellow-green legs, and bright red eyes. Males and females appear to be similar, but the females are slightly smaller. Juveniles appear duller with a brow to grey back and lighter underparts. The colors of the bill and legs are more muted than in adults.