PREFACE. 



Although preparations for the present work have been more or less 

 actively conducted for some twenty years past, as time and opportu- 

 nity permitted, the actual work of putting together the vast amount 

 of material accumulated during that period was not begun until Sep- 

 tember, LS!)4, when the author was directed by Dr. G. Brown Goode, 

 Assistant Secretary of the Smithsonian Institution, in charge of the 

 National Museum, to consider of paramount importance among his 

 official duties the task of "making available, through publication, the 

 results of the ornithological work of the Government, as represi'nted 

 in the collections of the Smithsonian Institution." The labor of collat- 

 ing references pertaining to more than 3,000 species of birds, verifying 

 citations of original descriptions, measuring many thousands of speci- 

 mens, and other time-consuming details connected with the preparation 

 of such a work has necessarily delayed the beginning of its publication; 

 but most of this drudgery having been disposed of, it is hoped that 

 future progress may be more rapid. 



In the following pages the attempt is made to describe every species 

 and subspecies, or definable form, of bird found on the continent of 

 North America, from the arctic districts to the eastern end of the. 

 Isthmus of Panama, together with those of the West Indies and other 

 islands of the Caribbean Sea (except Trinidad and Tobago), and the 

 Galapagos Archipelago; introduced and naturalized species being 

 included, as well as accidental or casual visitors. 



The classification presented is essentially that of the most recent and 

 advanced authorities,^ with such minor modifications as in the judg- 

 ment of the present author seem desirable. The imperfection of our 

 knowledge concerning the internal structure of many groups of birds, 

 however, makes an entirely satisfactory classification impossible at the 

 present time, and that here adopted must therefore be considered as 

 provisional only. An entirely sound classification of birds is a matter 

 of the future, requiring vastly extended investigations in the field of 

 avian anatomy and the expenditure of an enormous amount of time 

 and labor in elaborating the results. 



Some effort has been made to establish the proper terminology of 

 the higher groups, no fixed rule having been followed in this respect, 



' These are specially mentioned on pages 6, 7. 



