Part 11.] NATURAL ENEMIES OF BIRDS. 211 



Much time, thought and care have been given by the writer 

 of this paper to a study of the relations of birds and their 

 enemies, and the experience of many other observers has been 

 drawn upon in preparing this bulletin. Nevertheless, it may be 

 noted that the statements concerning the economic value of 

 the various creatures as set forth in these pages are supported 

 by comparatively little evidence. Thus they lack the apparent 

 authority that a fuller presentation of the evidence would have 

 given them. Had the original plan been followed many more 

 pages might have been filled with material fully confirming 

 the conclusions arrived at, but lack of space forbade, and it was 

 impracticable to secure the publication of the bulletin except 

 in its present abridged form. Therefore, the statements and 

 recommendations made and the conclusions drawn should be 

 taken as the judgment of an observer who, having opportunity, 

 has endeavored to inform himself fully, and who is confident 

 that his conclusions have value as guides to all who seek to 

 protect birds. 



The names of mammals given in this bulletin have been 

 brought down to date through the kindness of Dr. Glover M. 

 Allen. Those of North American birds have been taken from 

 the "American Ornithologists' Union Check-list," third edition 

 (1910). Other zoological names are such as are given in the 

 various publications quoted or cited. 



