A Respirometer for Determination of Metabolic Rates and Activity Patterns under Simulated Natural Conditions

moonl ight, twil ight, and dayl ight a re a p p r o x-imated. Oxygen consumpt ion in the open system is m e a s u r e d by a Beckman polar iz ing oxygen ana lyzer and recorded on an ana log recor-der. Act ivi ty is cons tant ly moni to red on an even t recorder t h r o u g h t h e use of two photoconduct ive cells in the r u n w a y to indica te m o v e m e n t be tween the nest box and act iv i ty chamber and by a microswi tch on t h e act ivi ty whee l to indicate runn ing; addi t ional ly, ro ta t ions of t he w h e e l a re total led by an electr ic counter. The a p p a r a t u s has p roved to be successful in 24-hour de t e rmina t ions of bo th oxygen consumpt io