PREFACE. 



The present report is a continuation of a systematic account of the vertebrate animals of 

 Korth America, collected or observed by the different parties organized under the direction of the 

 War Department for ascertaining the best route for a railroad from the Mississippi river to the 

 Pacific ocean. 



The collections of these expeditions having been deposited with the Smithsonian Institution 

 by the War Department, in compliance with an act of Congress, the undersigned was charged 

 by the Secretary of the Institution with the duty of furnishing the series of general reports 

 upon them, as called for by the Department. The account of the mammals having been 

 published in ISST, that of the birds is herewith furnished, prepared according to the plan 

 announced in the preface to that volume. 



As in the volume on the mammals, by the insertion of the comparatively few species not noticed 

 by the expeditions, this report becomes an exposition of the present state of our knowledge of the 

 birds of North America, north of Mexico. This addition, while rendering the work more valuable 

 to the reader, was absolutely necessary for the proper understanding of the western fauna, the 

 species of which are generally so closely allied to the eastern forms as to require in most cases 

 more minute and detailed descriptions of the latter than have been published. 



Certain portions of the report have been prepared by Mr. John Oassin, of Philadelphia^ and 

 Mr. GrEOKGB N. Lawrence, of New York, well known as the leading ornithologists of the United 

 States. Mr. Cassin has furnished the entire account of the Raptores, from p. 4 to 64, of the 

 Orallae from p. 689 to 753, and of the Alcidae from p. 900 to 918, in all about 1.35 pages. Mr. 

 Lawrence has written the article on the Longipennes, Totipalmes, and Colymbidae, from page 

 820 to 900, making 80 pages. 



To Mr. P. L. Sclater, of Londpn, acknowledgments are due for the examination of certain 

 specimens in European museums, and for other valuable aid in determining points of synonymy ; 

 some of his notes received too late for insertion in their proper places will be found in 

 Appendix A. Much assistance has also been rendered in various ways by Dr. J. G-. Cooper. 



In the introduction to the general report upon the mammals will be found a detailed account 

 of the different railroad surveying parties from which zoological collections were received 

 with their respective routes. For the proper understanding of the subject^ however, it will be 

 necessary to present a brief recapitulation in this place. 



1. Line of the 47xh parallel, under Governor 1. 1. Stevens. — This consisted of two principal 

 parties, one under Governor Stevens, passing from St. Paul, Minnesota, to the Pacific 

 accompanied by Dr. George Suckley, U. S. A, as surgeon and naturalist, the other under 

 Captain G. B. M'Clellan, proceeding from Vancouver to the Cascade mountains, -accompanied by 



