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 Oblogist, Goss’s Birds of Kansas, 
The Biological Survey Records, and from specimens in the Bendire 
and Ralph collections of the United States National Museum. 
