216 In Touch with Nature. 



sights. ' The call was invariably answered by some 

 birds in the rear, and it seemed to me that the 

 cries of the leaders mean an order to close up and 

 keep together.' As self-preservation is the first 

 law of nature, it is not a fanciful assumption that 

 the birds of the air are gifted with this instinct in 

 common with mankind; and that being so, the 

 power of communing with each other would seem 

 to follow as a necessary conclusion." 



But birdmen need not climb so high to observe 

 much of this, if, indeed, not every phenomenon. 

 The trackless highway of the moonlit river-valley 

 tells the same story. Anchor amid-stream when 

 the hunter-moon is full, and mark the sounds that 

 come floating earthward from the starlit skies. 

 Signal and reply, alarm and general response ; all 

 that transpires as hosts are hurrying by can be 

 noted here. Few suspect what a busy world there 

 is above the tree-tops. 



Amid all the varied changes in the tree above 

 me, one feature of bird-life never varied. An in- 

 digo-finch sang without ceasing. I make this 

 statement without qualification, although it con- 

 flicts with our views of physiology and usual ex- 



