Atlantic puffins at UK colonies including Bempton Cliffs and the Farne Islands face chronic breeding failure linked to declines in sandeels, their primary prey, driven by warming seas and industrial sandeel fishing in the North Sea.
Puffin chicks that receive insufficient food starve slowly in burrows over days to weeks, unable to cry out for help. Adults make increasingly desperate foraging trips but cannot locate adequate prey. Chronic breeding failure causes population decline without the acute visible suffering of mass mortality events, making the welfare harm less obvious but sustained across decades.