Guillemots nest in dense colonies on coastal cliff ledges and face welfare threats from human disturbance, predation, and climate-related shifts in prey fish availability.
Guillemot welfare at colony sites is acutely threatened by disturbance. Eggs are laid on bare ledges without nests; when adults are flushed by approaching people, boats, or drones, eggs roll off ledges and chicks fall into the sea below. Mass disturbance events can destroy a significant proportion of colony productivity in a single incident. Climate-driven reduction in sandeel availability forces adult guillemots into longer foraging trips, with chicks underfed and failing to fledge. The cumulative welfare impact of climate change on prey availability represents a systemic challenge that colony management cannot address at local level. Maintaining adequate viewing distances at breeding colonies and regulating boat traffic near breeding cliffs directly prevents colony disturbance welfare harms.