Puffins face a growing welfare challenge as warming seas reduce the abundance of sandeels and other small fish that form the bulk of their diet. UK breeding populations have declined significantly at many colonies.
Adult puffins that fail to find adequate fish experience reduced body condition and may abandon breeding attempts, leaving eggs and chicks to die. Chicks that receive inadequate food starve slowly in the burrow. Breeding adults unable to provision chicks adequately invest their own reserves, reducing survival probability in subsequent years. Sea warming and sandeel depletion from both climate change and industrial fishing create a cumulative welfare impact on entire breeding colonies. Individual welfare suffering is multiplied across the hundreds of thousands of birds at affected colonies.