A tropical bird in the Arctic (the cormorant paradox)

Seabirds, like all marine endotherms, have to compensate for the extensive cooling effect of water when diving. Alone among them, cormorants (Phalacro coracidae) have a wettable plumage and are predicted to require disproporti onately large amounts of food to balance heat losses. These piscivorous bir ds are thus thought to have a detrimental impact on fish stocks. However, w e show here that even in great cormorants from Greenland, which dive in waf er at 3 to 7 degrees C, daily food intake is lower than for well-insulated European seabirds. Despite their wettable plumage, cormorants thus appear t o manage their energy budgets in a remarkably efficient way. Nevertheless, the specific foraging strategies which enable this performance make cormora nts dependent on high prey density areas, a feature that should be taken in to account by future management plans.