Temperature regulation during flight in pigeons

Abstract

Temperatures recorded from a central area near the heart in homing pigeons showed increases of 1.5-2.0 C during flight and attainment of a relatively steady temperature of 44.5 C after approximately 1.5-2.0 min. flight. Subcutaneous temperatures over the pectoral muscles during flight tended to rise at high temperatures and to fall at low air temperatures. Measurement of subcutaneous heat flow from a small area over the pectoral muscles indicated a 6-fold increase during flight compared to that in inactive birds. These results were compared with heat flows measured through the feathers mounted on a heated source in a wind tunnel. The heat flow in this system was relatively independent of wind speed and direction within certain limits, active regulation of heat loss during flight was suggested to account for the much greater loss than occurred in the physical model.