Grey herons are successful generalist predators with stable UK populations, but face welfare challenges from cold winters, fish availability, and colony disturbance.
Individual grey heron welfare is primarily challenged during severe winter weather when prey becomes inaccessible under ice. Adults in poor body condition from difficult winters have reduced breeding success. Heronries disturbed during breeding cause adults to abandon nests with eggs or small chicks, causing welfare harm to individuals and breeding failure for the colony. Predation by foxes and mink at colony sites causes chick mortality. Seasonal changes in fish availability affect individual foraging success and condition. Welfare-focused management protects heronries from disturbance during the February to May breeding season.