8 PREFACE TO THIRD EDITION. 



Fifteenth) to the Check-List, published respectively in 'The Auk' for 

 July, 1908, and July, 1909. 1 



The changes in nomenclature from the second edition are numer- 

 ous, and result mainly from two causes: The recent unprecedented 

 activity in bibliographic research, abroad as well as in America, and 

 the strict, application of the law of priority. The critical examination 

 of many little known or wholly overlooked early publications, and 

 more careful scrutiny of others long well known, has led to the dis- 

 covery of many generic and specific names that, under universally 

 accepted rules of nomenclature, must be adopted. Many of these 

 changes result from the tendency heretofore to ignore rules of nomen- 

 clature when their observance entailed unwelcome changes in technical 

 names. With each year, however, the tendency is toward a strict 

 enforcement of generally accepted rules of nomenclature, the former 

 indifference to such rules rapidly giving place to their strenuous 

 observance, especially by the younger school of taxonomers. 



Many changes in generic names have resulted from raising to 

 generic rank various groups recognized merely as subgenera in the 

 first and second editions of the Check-List, their reduction in grade 

 by the original Committee having failed to meet with general 

 approval. 



The classification adopted for the Check-List a quarter of a century 

 ago does not now reflect current views on the relationships of many 



1 Eight Supplements to the Check-List have been published since the appearance of 

 the second edition, as follows: 



Eighth Supplement to the American Ornithologists' Union Check-List of North 

 American Birds. Auk, XIV, Jan., 1897, pp. 117-135. 



Ninth Supplement to the American Ornithologists' Union Check-List of North Ameri- 

 can Birds. Auk, XVI, Jan., 1899, pp. 97-133. 



Tenth Supplement to the American Ornithologists' Union Check-List of North Ameri- 

 can Birds. Auk, XVIII, July, 1901, pp. 295-320. 



Eleventh Supplement to the American Ornithologists' Union Check-List of North 

 American Birds. Auk, XIX, July, 1902, pp. 315-342. 



Twelfth Supplement to the American Ornithologists' Union Check-List of North 

 American Birds. Auk, XX, July, 1903, pp. 331-368. 



Thirteenth Supplement to the American Ornithologists' Union Check-List of North 

 American Birds. Auk, XXI, July, 1904, pp. 411-424. 



Fourteenth Supplement to the American Ornithologists' Union Check-List of North 

 American Birds. Auk, XXV, July, 1908, pp. 343-399. 



Fifteenth Supplement to the American Ornithologists' Union Check-List of North 

 American Birds. Auk, XXVI, July, 1909, pp. 294-303. 



For a list of the previous Supplements see the Preface to the second edition of the 

 Check-List (below, p. 15). 



