 The corn crake 's breeding habitat is grassland , particularly <unk> , and it uses similar environments on the wintering grounds . This secretive species builds a nest of grass leaves in a hollow in the ground and lays 6 – 14 cream @-@ coloured eggs which are covered with rufous blotches . These hatch in 19 – 20 days , and the black precocial chicks fledge after about five weeks . This crake is in steep decline across much of its former breeding range because modern farming practices often destroy nests before breeding is completed . The corn crake is omnivorous but mainly feeds on invertebrates , the occasional small frog or mammal , and plant material including grass seed and cereal grain . Natural threats include introduced and feral mammals , large birds , various parasites and diseases . 
