As otter populations recover in England, water vole colonies face increasing predation pressure that requires habitat management to reduce vulnerability.
Otter predation causes acute death stress in individual water voles and chronic flight-stress responses in colony members aware of predation risk. Colonies in simple, open habitat with no cover have limited escape routes. The welfare of water voles experiencing otter predation must be considered alongside the conservation welfare benefits of otter recovery — both are native species with equal protection status. Habitat complexity improvements benefit water voles without requiring control of otters.