 The Zapata rail is a medium @-@ sized , dark rail , approximately 29 cm ( 11 @.@ 4 in ) long . The upperparts are olive @-@ brown and the forehead , head sides and underparts are slate @-@ grey , with some white barring on the lower belly . The flanks are grey @-@ brown and the undertail is white . The iris , legs and feet are red , and the bill is yellow with a red base . The tail feathers are only sparsely barbed , and the wings are very short and rounded . The sexes are similar in appearance , but immature birds are duller and have olive feet and bill ; the chicks , as with all rails , are covered with blackish down . The Zapata rail 's call is described as a bouncing cutucutu @-@ cutucutu @-@ cutucutu similar to that of the bare @-@ legged owl , and a loud limpkin @-@ like kuvk kuck . However , these calls may actually be those of the spotted rail . 
