ROLES OF METABOLIC LEVEL AND TEMPERATURE REGULATION IN THE ADJUSTMENT OF WESTERN PLUMED PIGEONS (LOPHOPHAPS K?ZlZlWGINEA) TO DESERT CONDITIONS

l. Standard metabolic rate of western plumed pigeons (Lophophups femginea) averages 088 ml 0, (g hr)-’ during summer. This rate and the rate of evaporative water loss by these birds at 25°C are well below levels anticipated for birds of comparable size (81 g). 2. Summer and late fall birds did not have significantly different minimal thermal conductances, the means for both approximating l-8 kcal (ma hr “Q-l. 3. A relatively low level of metabolism and effortless evaporative cooling restrict the caloric burden for western plumed pigeons in the hot and arid regions of northwestern Australia where these birds live. Other pigeons closely associated with hot and arid environments also have relatively low metabolic rates.