NOCTURNAL DIGESTION, CLOACAL EXCRETION, AND DIGESTION-RELATED THERMOGENESIS IN PIGEONS (COLUMBA-LIVIA)

Two indicators of nocturnal digestive activity were identified in pige ons. Experiment 1 showed that a sizable amount of food empties from th e crop while pigeons are inactive during the night. Experiment 2 showe d that the number and volume of cloacal droppings during the night wer e directly related to the volume of food consumed during the day. The temporal pattern of cloacal droppings in the night was systematically related to features of the nocturnal body temperature (Tb) curves, sug gesting that excretory activity is thermogenic in its own right and/or that it is a marker for a thermogenic process in the upper digestive tract. Questions about the relationship between digestion-related ther mogenesis and shivering thermogenesis during the night in birds are hi ghlighted by these findings. Copyright (C) 1996 Elsevier Science Inc.