THE AUK: 



A QUARTERLY JOURNAL OF 



ORNITHOLOGY. 



vol. x. April, 1893. no. 2. 



THE GEOGRAPHICAL ORIGIN AND DISTRIBUTION 



OF NORTH AMERICAN BIRDS, CONSIDERED 



IN RELATION TO FAUNAL AREAS 



OF NORTH AMERICA. 1 



BY J. A. ALLEN. 



The present paper consists essentially of two parts. The 

 first treats of the probable geographical origin and present 

 distribution of the genera of birds represented in North America, 

 regardless of any inferences that may be drawn from this general 

 presentation of the facts of the case ; the second relates to the sub- 

 division of the continent into faunal areas of various grades, with 

 reference to their relationships, classification and nomenclature. 

 No very novel views, nor many new facts are presented, the paper 

 being in great measure a restatement of generally known facts in 

 a new sequence, with a view to giving them greater emphasis in 

 their bearing upon the special subject in hand. The leading ideas 

 here embodied have already been set forth by the writer in other 

 connections,' 2 but the evidence is here for the first time presented 



1 Read before the Tenth Congress of the American Ornithologists' Union, held in 

 Washington, D. C, Nov. 15-17, 1892. 



2 See the author's recent paper, 'The Geographical Distribution of North American 

 Mammals' (Bull. Am. Mus. Nat. Hist., Vol. IV, 1892, pp. 199-243, pll. v-viii), and 

 the earlier papers there cited. 



