260 



NATURE SKETCHES IN TEMPERATE AMERICA 



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The Bird Thermometer 



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i] 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 liis bhie coat, he is 

 now securely hiihlen among the shadows, 

 for the bright blue of his feathers is 

 sulxlucd several shades from his former 

 sunlit hue. One who has taken the 

 sunny i)ath along the wayside realizes 

 what the shelter of the trees means 

 to the birds. Hut let us see what 

 this difference in temperature really 

 amounts to. 



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. 

 The.se are the actual varied c-onditions that caused the indigo 

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

 diflPerent points affects the animal inhabitants I have noted 

 on every hand. 



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