【Abstract】 The resting metabolic rate ( RMR ) of birds correlates broadly with the climate of origin. In order to study the characteristics of thermoregulation in Little buntings and Chestnut buntings, are measured their resting metabolic rate ( RMR )at ambient temperature ( T a) ranged from 5℃ to 30℃ and calculated thermal conductance. The results are mainly as follows. 1. Thermal neutral zone ( TNZ ) for Little buntings ranged from 20℃ to 25℃ and for Chestnut buntings from 25℃ to 32 5℃. 2. The minimum metabolic rate of Little buntings and Chestnut buntings were 4 19 ml O 2/g·hr and 3 99 ml O 2/g·hr, respectively, which were 181% and 146% of the expected values that calculated from their body mass according to Aschoff and Pohl (1970). Above the upper critical temperature, RMR and T b increased. 3. The minimum thermal conductance ( C ) of Little buntings and Chestnut buntings were 0 26 ml O 2/g·hr·℃ and 0 23 ml O 2/g·hr·℃, respectively, which were 138% and 140% of the predicted values calcalated according to Aschoff (1981). In conclusion, the adaptation of Little buntings and Chestnut buntings to environmental climate were by the means of the slight higher level RMR and thermal conductance, and high intensity of chemical thermoregulation.更多还原