/ A. ALLEN. 31 



THE MIGRATION OF BIRDS. 



BY J^A. ALLEN. 



American Museum of Natural History, New York. 



The migration of birds has long attracted popular atten- 

 tion, references to the subject dating back to the days of 

 the prophet Jeremiah, who says : " Yea, the stork in the 

 heaven knoweth her appointed times ; and the turtle and 

 the crane and the swallow observe the time of their coming." 

 The early naturalists speculated upon the seasonal move- 

 ments of birds ; they noted the periodical appearance and 

 disappearance of the ' birds of passage,' but had little knowl- 

 edge as to where they went for their winter quarters. Certain 

 European birds were even supposed to be annually trans- 

 formed into other species for a portion of the year, or else 

 to pass the season of winter in a state of hibernation at the 

 bottom of streams or ponds. It was thought that the Cuckoo 

 became changed into a Hawk in winter, and that Swifts, 

 Swallows and Rails descended into the mud at the bottom of 

 ponds at the approach of cold weather. 



In later times the winter haunts of many species were 

 gradually discovered, and the fact of their long flights of 

 migration became well established. Yet the matter remained 

 to a large degree involved in mystery ; the migrations of 

 birds were thought to be in a sense automatic, under the 

 impulse and guidance of a blind, unerring " instinct " — in 

 other words, little short of miraculous. During recent years 

 the phenomena of migration have been made the subject of 

 careful and systematic investigation by thousands of ob- 



