Field voles are the most numerous UK mammal and form the base of the upland raptor food web, with population cycles creating welfare consequences throughout the food chain.
Field voles live fast, dangerous lives with high predation pressure and extreme weather exposure. Population crashes following peak years cause starvation and exposure mortality at enormous scale. Raptors dependent on voles suffer breeding failure and increased adult mortality during crash years, creating cascading welfare impacts through the food web. Maintaining diverse grassland structure — rough tussocky areas with dense cover — supports stable vole populations and the welfare of dependent predators.