Atlantic puffins are beloved seabirds whose welfare and population success depend critically on sand eel and small fish availability. Climate change is altering prey distribution in ways that threaten puffin breeding success at scale.
Puffin chick welfare during breeding failures is acute and prolonged. Chicks (pufflings) that do not receive adequate fish deliveries from parents starve slowly in their burrow over days. Parents make repeated food delivery trips, decreasing in frequency as fish become harder to find. Chicks that survive long enough may emerge from burrows underweight and unable to fledge successfully. The welfare dimension of mass breeding failures - entire colonies producing no surviving chicks in poor years - involves the suffering of thousands of individual animals dying from starvation in their natal burrows. Adult puffins that survive failed breeding seasons carry the physiological cost of intensive foraging effort without reproductive reward. The climate driver of these failures makes individual welfare directly contingent on global carbon policy.