H. Howell of the United States Biological Survey, for determin- 
ing species. Credit is given to other observers in the body of the 
text. 
They desire also to acknowledge the kindness of various 
magazines in allowing the use of photographs previously used in 
illustrating articles by the authors. 
The number with which the description of each bird be- 
gins is the one assigned to it by the American Ornithologist 
Union (third and last edition), and is convenient for reference 
to other works. 
The authors have not attempted to give full descriptions 
of the birds but only so much as seemed necessary for identifica- 
tion. For more complete descriptions they refer the observer to 
the principal works mentioned in the attached bibliography. 
