INTRODUCTION. 



THE classification, nomenclature, and numeration used in this 

 book are those of the A. 0. U, Check-List of North American Birds, 

 except that modern scientific usage has been followed in dropping 

 the possessive form in the vernacular names of species, as Clarke 

 nutcracker and Steller jay, instead of Clarke's nutcracker and Stel- 

 ler's jay. The rulings of the nomenclature committee of the Amer- 

 ican Ornithologists' Union have been followed, but new species upon 

 which the committee has not yet ruled have been included in foot- 

 notes under their proper places. 



In the matter of authorities, Ridgway's Manual of North Ameri- 

 can Birds, his Hummingbird paper, and Birds of North and Middle 

 America (Parts I. and II.) have been used at all points as standard 

 authorities, and the substance of keys and descriptions frequently 

 quoted. 



In the general treatment of species various authorities have been 

 followed. 



General Characters. These summaries of technical characters 

 have been abridged from the generic descriptions in Parts I. and II. 

 of Ridgway's Birds of North and Middle America, his monograph 

 on the Hummingbirds, and Coues's Key to North American Birds. 



Measurements. The measurements have been taken from the 

 second edition of Ridgway's Manual of North American Birds, from 

 Parts I. and II. of North and Middle America, with the millimeters 

 converted into inches, and, in the case of species not included in 

 these books, from the original descriptions. 



Nest and Eggs. Descriptions of nests and eggs are taken mainly 

 from Bendire's Life Histories of North American Birds, Ridgway's 

 Manual, second edition, The Auk, The Condor, The Osprey, The 

 Nidologist, The Ornithologist and Oologist, Goss's Birds of Kansas, 

 The Biological Survey Records, and from specimens in the Bendire 

 and Ralph collections of the United States National Museum. 



