INTERACTION OF BEHAVIORAL AND AUTONOMIC THERMOREGULATION IN COLD EXPOSED PIGEONS

The interaction of behavioral and autonomic thermoregulation in pigeons during ambient cold loads (Tload= +10° to -10 °C) was studied by simultaneous measurements of instrumental response rate for heat reinforcement (RF rate) and electromyographical shivering activity (EMG). Instrumental thermoregulation consistently accounted for only a fraction of overall thermoregulation which consistently involved increased heat production by shivering. RF rate increased with decreasing Tload and vice versa (Fig. 2A). As the result, temporal mean ambient temperature (-Ta) changed only little with Tload (Fig. 2B). EMG activity was closely correlated with -Ta (Fig. 3) and, thus, did not increase with decreasing Tload. Shivering and instrumental thermoregulation could mutually replace each other to a considerable extent at a given Tload (Fig. 4B). Changes of RF rate in response to tepwise changes of Tload overcompensated the changes of Tload. This resulted in inverse changes of -Ta and, consequently, of EMG activity. Skin temperatures in well feathered areas changed in parallel with -Ta, whereas the rates of temperature changes (ΔT/Δt) at exposed areas increased with decreasing Tload and vice versa. © 1979 Springer-Verlag.