The merlin, the UK's smallest raptor, nests on upland moorland and heathland, hunting small birds in low, fast pursuits across open ground. Its welfare is tied to moorland quality and prey availability.
Merlin welfare during breeding is sensitive to moorland management. Heather burning for grouse management creates the open structure merlins use for hunting, but intensive burning at high frequency can be detrimental. Predator control on grouse moors — while controversial — incidentally benefits merlin breeding success by reducing crow and fox predation of ground nests. The biggest welfare threat to merlins is deterioration of upland habitats through both undergrazing (rank vegetation closing over) and overgrazing (removing heather diversity). Winter welfare in coastal areas, where merlins hunt reed buntings and finches, is affected by disturbance at key roost and foraging sites.