 The breeding corn crake population had begun to decline in the 19th century , but the process gained pace after World War II . The main cause of the steep declines in much of Europe is the loss of nests and chicks from early mowing . <unk> dates have moved forward in the past century due to faster crop growth , made possible by land drainage and the use of <unk> , and the move from manual grass @-@ cutting using <unk> to mechanical <unk> , at first horse @-@ drawn and later pulled by <unk> . <unk> also means that large areas can be cut quickly , leaving the crake with no alternative sites to raise either a first brood if suitable habitat has gone , or a replacement brood if the first nest is destroyed . The pattern of mowing , typically in a circular pattern from the outside of a field to its centre , gives little chance of escape for the chicks , which are also exposed to potential animal predators . Adults can often escape the <unk> , although some <unk> females sit tight on the nest , with fatal results . 
