157681 Cuckoo - Cuculus canorus - with Reed Warbler foster parent. L 33-35cm. Secretive summer visitor with intriguing lifestyle. Heard more than seen. Recalls a Sparrowhawk in flight. Feeds mainly on hairy caterpillars. Sexes sometimes separable. Adult male, and most females have blue-grey head, neck and upperparts; underparts are white and barred. Some adult females are brown and barred on head, neck and upperparts; underparts are white with dark bars. Juvenile is similar to brown adult female but with white nape. Voice Male utters distinctive cuck-oo song; female has bubbling call. Status Local summer visitor. Range dictated by occurrence of songbirds used for nest parasitism; host species include Meadow Pipit, Dunnock and Reed Warbler.