Wing‐spreading, wing‐drying and food‐warming in great cormorants Phalacrocorax carbo

Abstract

Wing‐spreading of cormorants (Phalacrocoracidae) is a characteristic and enigmatic aspect of their behavioural repertoire. It has been suggested to have a range of functions including wing‐drying, food‐warming, and social signalling of foraging success. We investigated two of these putative roles by comparing the wing‐spreading behaviour of fed and unfed animals after they had been swimming and diving. The duration of wing‐spreading was correlated only with time spent on the water. The ingestion of food did not influence the duration of wing‐spreading, a finding that supports a wing‐drying, rather than a food‐warming, function.