BIRD ENERGETICS - EFFECTS OF ARTIFICIAL RADIATION

Radiant energy reduces oxygen consumption in birds; this reduction is correlated with feather color, being greater in dark birds (26 percent reduction) than in white ones (6 percent reduction). With radiant energy (basking), the cowbird effectively increased its insulation, thus shifting the lower end of the zone of thermal neutrality down by as much as 10°C (35° to 25°C).