Geographic Variation in the Bioenergetics of the House Sparrow

The introduction of the House Sparrow, Passer domesticus, into North America has been a fortuitous natural experiment in avian adaptability. Several attempts have been made to demonstrate morphological variations between various localities resulting from natural selection. The present paper is an examination of some components of the bioenergetics of the House Sparrow with regard to inter-populational differences and their possible adaptive roles. Kendeigh (1934, 1944, and 1949), Seibert (1949) and Davis (1955) have already described existence metabolism and other aspects of the energetics of House Sparrows from central Illinois (latitude 40 °N). In this same area, Barnett (1970) studied mechanisms of seasonal acclimatization, and Zar (1967) experimentally assessed the influence of temperature on lipid composition. Hudson and Kimzey (1966) reported that Houston, Texas, populations had lower standard metabolic rates than those of Michigan, Colorado, and New York.