The corncrake has disappeared from most of its former British range but remains in western Ireland. Its welfare depends on delayed hay cutting that allows chick-rearing to complete before mowing.
Corncrakes killed by mowing machinery die violently and rapidly, but the impact on welfare at the population level is severe and cumulative. Adults that lose nests and chicks to early cutting may attempt relaying, but time pressure as the season advances reduces the viability of replacement broods. The energy cost of repeated failed breeding attempts reduces adult body condition before autumn migration. The fear response to approaching machinery causes adults to flush repeatedly from vegetation cover, expending energy and risking aerial predation. Delayed cutting of even a proportion of fields in corncrake territories significantly improves breeding success and reduces cumulative individual welfare costs.