LN ERO DUC LrEON. 
In Crassirication, NoMENcLATURE, and Numeration the present work corre- 
sponds strictly with the “Check List of North American Birds” published by the 
American Ornithologists’ Union,’ which represents the joint labors of a “ Commit- 
tee on Classification and Nomenclature” appointed by the Union during its first 
Congress, held in New York City, September 26-29, 1883. 
During the year which has elapsed since the publication of the A. O. U. Check 
List several species have been added to the North American fauna, while others 
have been for the first time described. These are of course included in the present 
work, being interpolated in their proper places? At the same time, it has been 
considered desirable,'in the interest of the student of North American Ornithol- 
ogy, to include, for reasons stated farther on,’ certain extralimital species from 
contiguous countries. All such additional species have, however, been carefully 
distinguished typographically, in order that no confusion may arise, the method 
of discrimination being as follows: 
(1) All species which are undoubtedly North American, even though of doubt- 
ful validity, are in larger type, those given in the A. O. U. Check List proper being 
numbered as in that list, while eighteen of the twenty-six species composing the 
so-called “ Hypothetical List,”* and also those subsequently added to the fauna, are 
preceded by a dash (—) instead of a number. (2) All species which have not been 
established as North American (the majority never having been claimed as such) 
are printed in smaller type, and have neither a number nor a dash. 
The GroGRAPHICAL Limits are also, so far as numbered species are concerned, 
those of the A. O. U. Check List ; but practically these limits have been enlarged so 
1 The Code of Nomenclature | and | Check List | of North American Birds | Adopted by the American 
Ornithologists’ Union | Being the Report of the Committee of the Union on Classification and Nomenclature | 
(Motto) | —— | New York | American Ornithologists’ Union | 1886 | [8vo., pp. i-viii, 1-392.] 
2 For lists of these additional species, see Appendix, pages 591-594, 
8 See under “ Geographical Limits.” 
4 Consisting of species which have been recorded as North American, but whose status as North Ameri- 
can birds is doubtful, either from lack of positive evidence of their occurrence within the prescribed limits . . . 
or from absence of satisfactory proof of their validity as species.” Of the twenty-six species constituting this 
list, eighteen are unquestionably North American (one of them having been recently established as such), while 
the remaining eight have very scant claims to a place in our fauna. 
ix 
