INTRODUCTION. 21 



abnormally dark or black. In albinism, which Ts not uncom- 

 mon, birds are partially or whoUy abnormally white (or even 

 yellow) ; sometimes they are partly bleached. Such condi- 

 tions of plumage need cause confusion only among birds of 

 the same genus, and rarely then, being seldom complete.] 

 There are often varieties,* geographical races, or forms ren- 

 dered appreciably distinct by the effects of climate, etc. By 

 a strict definition of the term, varieties must have different 

 distributions (at least during the breeding-season), though 

 accidental stragglers may occur far from their usual habitat. 

 A specific type is usually the variety first named. Hyhrids, or 

 " crosses," are the joint offspring of two species, but they do 

 not often occur among birds in a natural state. 



A bird's scientific name consists of a generic (subgeneric) 

 and specific, or also subspecific, title; e. g., Turdus {Hylo- 

 cichla) swainsoni, var. alicice, or simply Turdus alicice. ^® f 

 Family names end in idee, those of subfamilies in vnoe. Sci- 

 entific names are usually begun with a capital, are italicized, 

 and, when following English names, put in parentheses. 

 Specific names, however, are ordinarily spelt without a capital, 

 unless derived from proper names. J 



Note. — Many still existing scientific names are unworthy 

 of retention, but they have not been altered in this volume on 

 account of the established rule of priority, which necessitates, 

 however, many incongruities. The authorities for these names 

 are given in the second index. Great care has been bestowed 

 upon the orthography of English names, since great latitude 

 exists in this respect, no system being yet established. Certain 

 rules have here been followed, with the exceptions produced 

 by general or the best usage. 



• " Subspecies " is the term now in the connecting " var.'' ; e. g., Turdus 



general iise for geographical forms. — didw Uchndli. — W. B. 

 ■TO' g X The capitalization of proper spe- 



16 Turdus alicioe is often ranked as a cific names has heen discontinued by 



species. American ornithologists, whose custom 



t The names of subspecies are now in this respect has been followed m the 



written as simple trinomials without present edition of Mr. Minot's book. — 



W.B. 



