28o Natural History Bulletin. 



the habit the bird has of circhng around the hunter, stopping 

 in each tree long enough to beguile him into thinking the 

 songster is at last located, and then flitting slyly to the next 

 and repeating the performance. In addition to this, however, 

 the voice is exceedingly difficult to locate, even when the bird 

 remains in one spot. 



Eleven specimens secured. 



Merula migratoria. (Linn,). American Robin. Very 

 abundant at Grand Rapids, although none were seen at 

 Chemawawin. 



A reference to the appended tables shows that the great 

 majorit}^ of the species secured b}- us are familiar migrants 

 in Iowa and are winter residents in the southern part of 

 North America, or in Central America. It is still more inter- 

 esting to note that a majority of the species breeding within 

 the Arctic Circle are winter residents of sub-tropical or tropi- 

 cal America. This implies a biennial migration of about three 

 thousand miles on the part of a large proportion of our North 

 American birds. 



The fact of this migration is now pretty generally under- 

 stood. The origin of the migratory habit is very happily and 

 tersety explained b}^ Dr. Leonhardt Stejneger.i It might be 

 questioned, however, whether this habit is solely an instinc- 

 tive one, or partly, at least, the result of a direct stimulus or 

 suggestion afforded by external conditions coming with the 

 return of the season of migration. 



If a direct and immediate incentive or stimulus to mifjration 

 can be found, a stimulus reasonably competent to start the 

 birds and keep them moving to the end of their migratory 

 journey, it would be more satisfactory to many minds than 



1 Standard Natural History, Vol. IV., p. 17. 



