COLE ON THE MIGRATIONS OF BIRDS. (J~ 



PArERS READ IN THE SECTION OF ZOOLOGY. 



SUGGESTIONS FOR A METHOD. OF STUDYING THE MIGRA- 

 TIONS OF BIRDS. 



BY LEOX J. COLE. 



Many theories have been advanced to acceunt for the striking migra- 

 tions of birds, and as has been shown by Walhice/ and in a somewhat 

 modified way by Brooks,- the law of natural selection is capable of 

 accounting for the origin of this habit, which has become so perma- 

 nentlv fixed in nearly all of our birds. But there are many phenomena 

 connected with migration to account for which even satisfactory hypoth- 

 eses are not as yet forthcoming, chief among which may be cited the 

 question of how birds are able to find their way unerringly over hun- 

 dreds, or even thousands, of miles of land and water to a particular 

 locality which they have left the previous year. Before these ques- 

 tions can be answered a much better knowledge of the facts is neces- 

 sary. 



Various methods have been employed for obtaining data relative to 

 the migration of birds, and an immense amount is contained in miscel- 

 laneous notes scattered throughout the ornithological literature. These 

 notes embody in large part the records of single observers on the flights 

 of birds, their abundance at various times of year, and especially 

 records of their first arrival in the spring. The collection of this last 

 mentioned data, together with some further notes on the time the bird 

 became common, whether it breeds at the station of the observer, etc., 

 has been carried on in an extensive and systematic way in this country 

 for many years by the United States Department of Agriculture, under 

 the able direction of Dr. C. Hart Merriam. A very excellent report 

 of some of the results of the first of this work in the Mississippi Valley 

 was prepared by Piof. W. W. Cooke,^ but so far as I know nothing of 

 the kind has been attempted with the mass of data which must have 

 accumulated since that time. During the period of its activity the 

 Michigan Ornithological Club appointed a committee to collect similar 

 data in the Great Lake region, blanks being used almost identical with 

 those of the Department of Agriculture. 



1 Nature, X., p. 459. 



"The Foundation.s of Zoology, chapter V. New York, ISO'J. 



* Report on Bird Migration in the Mississippi Valley in the Y'ears 1884 and 1885, by W. 

 W. Cooke. Edited and revised bv Dr. C. Ilai-t Merriam. U. S. Dept. Agr.. Division of Economic 

 Ornithology, Bulletin No. 2. -Washington, 1888. 



