13 PREFACE TO THIRD EDITION. 
6. Numbering of species omitted. 
7. Stragglers or accidental visitors are designated by the matter relating 
to them being bracketed. 
8. Subspecies are distinguished typographically by the use of smaller 
type. 
9. Addition of a map showing the principal life zones of North America. 
At the meetings of the Committee held in 1905 and 1906, and also 
later, the various parts of the work connected with the preparation 
of a new Check-List were assigned to different members of the Com- 
mittee, acting as subcommittees, with whom were sometimes asso- 
ciated other members of the Union familiar with special questions. 
The Committee is thus especially indebted to Messrs. Chapman, 
Cooke, A. K. Fisher, J. Grinnell, Lucas, Nelson, Oberholser, Osgood, 
and Stejneger for assistance in its work. To Dr. Richmond was 
assigned the task of verifying the references and citations in the second 
edition of the Check-List, and of preparing the nomenclatural part of 
the new Check-List for publication. A special subcommittee on 
nomenclature was established, consisting of the Chairman, Richmond, 
and Stone. ‘To Mr. Ridgway (with the codperation of Dr. Stejneger) 
was assigned the task of drafting a new classification, which, however, 
it was finally decided not to use, for reasons already given. ‘The 
determination of type localities of species and subspecies was assigned 
to Drs. Richmond and A. K. Fisher. The revision of the list of 
fossil North American birds was referred to Drs. Richmond and Lucas. 
The accentuation of the technical names was referred to a sub- 
committee consisting of the Chairman, Dr. Dwight, and Mr. 
Batchelder. 
The preliminary revision of the geographical ranges of the species 
and subspecies was undertaken by Mr. Stone, while the final revision 
and preparation of the manuscript for the press was assumed by Dr. 
Merriam, who, with the aid of members of his scientific staff (Biologi- 
cal Survey) has given the subject thorough consideration. It was at 
first intended to base the revision on an examination of published 
records, but later these were supplemented by the resources, in large 
part unpublished, of the Biological Survey. The ranges as now 
given therefore embody a large amount of original research, and 
may be taken as reflecting the present available knowledge of the 
subject, for which the Union owes a lasting debt of gratitude to 
