The Development of Endothermy and Existence Energy Expenditure in Herring Gull Chicks

Abstract

Herring gull chicks maintain homeothermic body temperatures in moderate ambient temperatures by 24 h after hatching, and in all but extreme temperatures after 3 days. A crude estimate of total metabolic costs of non-active chicks in the natural environment shows that a much smaller proportion (7%) is expended on thermoregulation than in double-crested cormorant chicks (38%). The magnitude of this difference suggests that chick energetics might be important in the study of parental reproductive strategies.