REMARKS ON THE ORIGIN OF BIRD MIGRA- 

 TION.i 



BY FRANK M. CHAPMAN. 



As A TEXT for the remarks I have to offer on this subject I 

 have taken the following paragraph from Dr. Allen's paper on 

 the 'Origin of the Instinct of Migration in Birds'^: "Nothing 



1 Read at the Eleventh Congress of the American Ornithologists' Union, held in 

 Cambridge, Mass., Nov. 20-23, 1893. 



2 Bull. N. O. C, V, 1880, pp. 151-154. 



influences which may have aided climatic conditions in establish- 

 ing the habit of migration and which are probably effective in 

 governing it to-day. 



Most animals have an instinctive desire for seclusion during 

 the season of reproduction, and when this season approaches will 

 seek some retired part of their range or haunts in which to rear 

 their young. Even our domesticated hens, turkeys, ducks, and 

 pea-fowl, if given freedom, often travel a greater or less distance in 

 search of a place where they may conceal their nests. Many 

 species of tropical sea-birds resort each year to some rocky islet, 

 situated perhaps in the heart of their habitat, where they may 

 nest in safety. This is not migration in the true sense of the 

 word, but nevertheless the object is the same as that which 

 prompts a Plover to migrate to the Arctic regions, and, be it further 

 noted, the moveprent is just as regular. These sea-birds pass 

 their lives in the tropics, their presence or absence in any part 

 of their range being largely dependent upon the food-supply. 

 But, as in the case of a Warbler which nests in Labrador, they 



