Atlantic puffin breeding success is declining in many colonies as climate change alters the availability and distribution of sand eels and other prey fish during the critical chick-rearing period.
Pufflings that receive insufficient food during their 40-day nest period starve slowly before parents abandon the burrow. Starvation in nestlings causes progressive weakness, hypothermia, and death over days. Adults that successfully raise chicks invest enormous energy in long foraging flights when prey is scarce. The multi-decade lifespan of adult puffins means that several consecutive breeding failures can drive rapid population decline even when adult survival remains high. Climate-driven prey shifts are difficult to mitigate directly, making emissions reduction the most impactful long-term welfare intervention. Marine protected areas that preserve sand eel spawning and nursery habitat provide partial protection.