Animal Sciences Commons^™

Seasonal And Geographic Variation Of Cold Resistance In House Finches Carpodacus Mexicanus, William Dawson, Richard Marsh, William Buttemer, Cynthia Carey

Richard Marsh

The house finch (Carpodacus mexicanus) is resident in tropical and subtropical regions as well as in localities having relatively severe winters. The extent of its winter acclimatization was assessed in freshly captured individuals of this species from southern California and Colorado. In severe cold stress tests involving exposure to Tₐ < −60 C, the former did not remain homeothermic any longer in winter than in late spring, whereas the Colorado birds did (8.8 vs. 97.5 min; P < .001). The capacity for winter acclimatization evident in these Colorado individuals was correlated with modest winter fattening, a response lacking in those from southern …