MIGRATION. 



Exclusive of the work of the United States Biological Sur- 

 vey but little effort has been made in this country toward 

 detailed co-operative investigations on a large scale of this 

 phenomenon ; therefore the finished systematized report pro- 

 duced from the vast mass of accumulated data should be the 

 most important publication ever issued by that branch. We 

 know very little of the migratory habits of the Flicker beyond 

 that it occurs in large loose flocks by night, published data 

 being meagre ; under the circumstances no excuse need be 

 offered for the tabulated forms, incomplete as they are, owing 

 to the varied terms of years, 1875 to 1899, and fragmentary 

 nature of the reports. In spite of all that has been said to the 

 contrary, the homing instinct must have much to do with the 

 annual northward movement and the alleged failure of the 

 food supply has less to do with the retrograde movement than 

 the approach of cold and stormy weather and consequent dis- 

 appearance of sheltering foliage. In common with a large 

 number of our birds, the Flicker is peculiarl}^ sensitive to me- 

 teorological changes which govern its movements to a large 

 extent. The di.scussion of the probable causes of the semi- 

 annual restlessness and irresistible impulse to move to more 

 favorable climes lies beyond the .scope of this paper. If mi- 

 gration consisted of a uniform dispersion and progression 

 throughout the country instead of lines of flight along the 

 coast, rivers and valleys and in irregular waves, the signifi- 

 cance of the dates would be more apparent ; as it is, a record 

 may be that of the arrival of a Summer resident or transient, 

 according to the remoteness or proximity to the line of flight., 

 W. W. Cooke in " Bird Migration in the Mis.sissippi Valley," 

 states that the Flicker travels faster on the east than the west 

 side of the Mississippi river. He estimates its average daily 

 speed at about 12 miles. My calculations place the relative 

 speed at about the same figure, Intt varying according to season 



