THE UNCHARTED SKY 127 



you'll find them nesting at the northern limit of 

 trees, all the way across from Alaska to Labrador. 

 No matter where they nest though, as soon as the 

 fledgelings are old enough and the molt is com- 

 plete, every one of those millions of tiny birds 

 takes the sam^e invisible railroad route through 

 the air from Alaska or Labrador to Key West, 

 thence to Cuba and Jamaica and so on to the coast 

 of South America." 



*'How can yo' tell what way they go?" ques- 

 tioned Bull in a disbelieving voice. 



' ' That 's simple enough, ' ' came the reply. ' ' On 

 their migration route they are reported by our ob- 

 servers, all along the line, and they are not seen 

 anywhere else. We know they nest in Labrador. 

 "We know they winter in Brazil. We know in the 

 fall, at the same date every year, they appear suc- 

 cessively in Florida, Cuba and Jamaica. They 

 are never reported from the southwestern states 

 and are unknown in Mexico. How's that for 

 proof?" 



'^ Sounds right enough," said the pot-hunter 

 grudgingly, but it was evident that he w^as not 

 convinced. "Do any 0' the small birds that nest 

 roun' here go travelin' that way?" he queried. 



"Lots of 'em," was the answer. "Take the 



