A REVISION OF THE FORMS OF THE HAIRY WOODPECKER 

 (DRYOBATES VILLOSUS [LINNAEUS]). 



By Harry C. Oberholser, 



Assistant Ornithologist, Department of Agriculture. 



A cursory examination of the hairy woodpeckers (Dryobates villosus 

 [Linnaeus]), made some time ago, showed conclusively that they 

 were much in need of revision. This task I finally undertook, 

 largely at the request of Mr. Ridgway, who generously placed at my 

 disposal all the material he had gathered, and all the measurements 

 he had made for use in preparing his account of this species for the 

 forthcoming fifth part of his "Birds of North and Middle America." 

 This material consists of altogether 1,070 specimens, and comprises 

 the collections of the United States National Museum, including that 

 of the Biological Survey; the American Museum of Natural History; 

 the Museum of Comparative Zoology at Cambridge, Massachusetts, 

 including the Bangs collection; the Academy of Natural Sciences of 

 Philadelphia; the Carnegie Museum of Pittsburg, Pennsylvania; and 

 the Field Museum of Chicago. With this excellent series, which repre- 

 sents all the forms of the species, most of them very satisfactorily, 

 it has been possible to work out the distribution of the various races 

 in considerable detail, which the accompanying map graphically 

 represents. 



The hairy woodpecker, as a species, ranges from Alaska and 

 northern Canada south to Panama, and has 14 currently recog- 

 nized forms, which the present investigation increases to 20. It 

 is preeminently a bird of the forest, and in eastern and northern 

 North America frequents both lowlands and highlands indiscrimi- 

 nately; but in the arid western United States and Mexico perforce, 

 in Central America apparently from choice, it is an inhabitant of the 

 mountains. Most of the forms are sedentary, but three — Dryobates 

 villosus septentrionalis, Dryobates villosus villosus, and Dryobates vil- 

 losus Jiarrisi — have a well-marked southward movement in autumn 

 and winter. Nearly all conform very well to the boundaries of the life 

 zones, as now understood, although they range usually through two 

 or exceptionally even three zones. The distribution of a few of the 



Proceedings U. S. National Museum, Vol. 40— No. 1840. 



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