eine Thirteenth Supplement to the A. O. U. Check-List. 7 
THIRTEENTH SUPPLEMENT TO THE AMERICAN 
ORNITHOLOGISTS’ UNION CHECK-LIST OF 
NORTH AMERICAN BIRDS.! 
At a session of the A. O. U. Committee on Nomenclature held 
in Washington in April, 1904, the following rulings were adopted. 
Departures from the nomenclature of the Check-List due to the 
adoption by authors of the 12th instead of the 1oth edition of 
Linneeus’s ‘ Systema Nature,’ and those which are merely expres- 
sive of personal preference or opinion, without the presentation of 
new evidence, were not considered as requiring the formal reaffir- 
mation of the Committee’s previous rulings in such cases. 
Owing to the limited time at the Committee’s disposal, and the 
absence of the requisite material, many cases were deferred for 
later action. In view of the present large number of these it was 
decided to refer as many of them as possible to subcommittees for 
investigation, with instructions to report thereon to the full Com- 
mittee at its next session, which it is hoped can be so planned that 
both time and material will be available to enable the Committee 
to dispose of practically all of the cases then awaiting action. 
In preparing the present Supplement it has been deemed advis- 
able to omit the secondary references to species and subspecies, 
together with the concordance and geographical ranges, and also 
the list of deferred cases. 
(J. A. ALLEN, Chairman. 
| CHARLES W. RICHMOND, Secretary. 
WILLIAM BREWSTER. 
Committee. J JONATHAN DwiGur, JR. 
C. Hart MERRIAM. 
ROBERT R1DGWAY. 
WITMER STONE. 
1 Five Supplements have been issued since the publication of the Second 
Edition of the Check-List in 1895, as follows : 
Eighth Supplement, Auk, XIV, Jan., 1897, pp. 117-135. 
Ninth Supplement, Auk, XVI, Jan., 1899, pp. 97-133. 
Tenth Supplement, Auk, XVIII, July, 1901, pp. 295-320. 
Eleventh Supplement, Auk, XIX, July, 1902, pp. 315-342. 
Tweifth Supplement, Auk, XX, July, 1903, pp. 331-368. 
