J. 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 wellestablished. 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- 
