Black-legged kittiwakes are declining rapidly in many North Sea colonies, with welfare implications from breeding failure and the stress of unproductive seasons.
Prolonged breeding failure causes energetic costs without reproductive benefit. Adults that fail repeatedly show physiological stress markers and reduced body condition over time. Chicks that hatch but starve suffer before death or abandonment. Adults surviving storm events that destroy entire clutches lose entire seasonal breeding investment. The stress of repeated failure in a changing ocean represents cumulative welfare harm.