Circadian metabolic responses to food deprivation in the Black-shouldered kite

Circadian metabolic responses to food deprivation were measured in Black-sh ouldered Kites (Elanus caeruleus) at thermoneutral and cold ambient tempera tures. The basal metabolic rate (BMR) of the kites aas 60-70% of that predi cted by various allometric equations. They displayed marked circadian rhyth ms of BMR and body temperature (T-b), but did not show any indication of me tabolic depression or adaptive hypothermia in response to food derivation. Instead, moderate reductions in metabolic rate and T-b were observed, resul ting in significant reductions in the daily energy expenditure. Thc conserv ative metabolic traits shown by the kites and their reponses to food depriv ation suggest tolerance of periodic, limited food supplies.