HUDSON 



Figure 1. Oxygen consumption (corrected to STP) of a Poor- will ( Phalaenoptilus 

 nuttallii) plotted against ambient temperature. Each point is the minimum consump- 

 tion maintained for at least 30 minutes in a post- absorptive bird. The solid line is 

 fitted by eye and is extrapolated as the dashed line to intercept with the abscissa. 

 This intercept indicates only an approximate conformity with Newton's Law of 

 Cooling. 



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