Samenvatting

Maintaining energy balance is a challenge shared by all animals which has resulted in an enormous variety of strategies for maintaining this vital balance. One of these is torpor, a mechanism that slows down basic metabolic rate (BMR) which results in a low expenditure of energy otherwise used to maintain homeostasis. Torpor is often seen as an emergency response used by animals when food resources and/or ambient temperatures are low. However recent evidence suggest that torpor use in birds is a common energy-saving strategy that is not necessarily reserved for energetic emergencies, but a more dynamic response to ambient temperatures that involves flexible adjustments to environmental factors.