260 NATURE SKETCHES IN TEMPERATE AMERICA 



ife V/ 



The Bied Thebmometek 



ITH open mouth and panting for 

 breath, the indigo bird flies from 

 the ground to the deep shadows 

 of a hickory tree beside the road. 

 Every feature of his attitude is an 

 expression of the excessive heat of the 

 July day. Despite his blue coat, he is 

 now securely hidden among the shadows, 

 for the bright blue of his feathers is 

 subdued several shades from his former 

 sunlit hue. One who has taken the 

 sunny path along the wayside realizes 

 what the shelter of the trees means 

 to the birds. But let us see what 

 this difference in temperature really 

 amounts to. 



I At ten in the morning, beside the 



shaded door of the house, the thermom- 

 eter registered eighty-three degrees, but 

 see how rapidly the mercury ascends as the thermometer is 

 changed. In the course of a number of minutes the mercury 

 runs up to one hundred and sixteen degrees when the instru- 

 ment is placed on the ground. Then, fixing the instrument in 

 mid-air so that the air circulates about -it in the sunlight, it 

 soon drops to one hundred and three degrees Fahrenheit. 

 These are the actual varied conditions that caused the indigo 

 bird to seek cover. How much this change of temperature at 

 different points affects the animal inhabitants I have noted 

 on every hand. 



