 The water rail ( Rallus aquaticus ) is a bird of the rail family which breeds in well @-@ vegetated wetlands across Europe , Asia and North Africa . Northern and eastern populations are migratory , but this species is a permanent resident in the warmer parts of its breeding range . The adult is 23 – 28 cm ( 9 – 11 in ) long , and , like other rails , has a body that is flattened laterally , allowing it easier passage through the reed beds it inhabits . It has mainly brown upperparts and blue @-@ grey underparts , black barring on the flanks , long toes , a short tail and a long reddish bill . Immature birds are generally similar in appearance to the adults , but the blue @-@ grey in the plumage is replaced by buff . The downy chicks are black , as with all rails . The brown @-@ cheeked rail , R. indicus , has distinctive markings and a call that is very different from the pig @-@ like squeal of the western races , and is now usually split as a separate species . 
