 The corn crake is a medium @-@ sized rail , 27 – 30 cm ( 11 – 12 in ) long with a wingspan of 42 – 53 cm ( 17 – 21 in ) . Males weigh 165 g ( 5 @.@ 8 oz ) on average and females 145 g ( 5 @.@ 1 oz ) . The adult male has the crown of its head and all of its upperparts brown @-@ black in colour , streaked with buff or grey . The wing coverts are a distinctive chestnut colour with some white bars . The face , neck and breast are blue @-@ grey , apart from a pale brown streak from the base of the bill to behind the eye , the belly is white , and the flanks , and undertail are barred with chestnut and white . The strong bill is flesh @-@ coloured , the iris is pale brown , and the legs and feet are pale grey . Compared to the male , the female has warmer @-@ toned upperparts and a narrower duller eye streak . Outside the breeding season , the upperparts of both sexes become darker and the underparts less grey . The juvenile is like the adult in appearance , but has a yellow tone to its upperparts , and the grey of the underparts is replaced with buff @-@ brown . The chicks have black down , as with all rails . While there are no subspecies , all populations show great individual variation in colouring , and the birds gradually become paler and <unk> towards the east of the range . Adults undergo a complete moult after breeding , which is normally finished by late August or early September , before migration to south eastern Africa . There is a pre @-@ breeding partial moult prior to the return from Africa , mainly involving the plumage of the head , body and tail . Young birds have a head and body moult about five weeks after hatching . 
