158 



NATUEAL HISTORY COLLECTIONS IN ALASKA. 



and other mountains of the west to the south is found the form known as dorsalis, which, as will 

 be seen in the appended description, is a well-marked race. From Fort Simpson and Fort Liard, 

 on the headwaters of the Mackenzie Eiver north, including also the Anderson and Lower 

 Mackenzie Elvers, and to the west, covering the entire northern portion of Alaska, on the south- 

 eastern shore of the Territory, its range merges into that of dorsalis, as mentioned previously. The 

 differences existing between ammcaw^is and aJascensis mil be seen by the following parallel tables, 

 in which the northern form is compared directly with specimens from the Adirondacks: 



Americanos. 



Crown the same in both forms. The nuchal collar 

 frequently indistinct, and never forming a 

 heavily-marked hand. The upper half of the 

 dorsum is frequently black, almost unspotted, 

 and is never heavily or thickly barred or 

 marked with white ; the lower half of dor- 

 sum is frequently rather profusely barred with 

 white, but rarely equaling even those Alaskan 

 specimens with the lightest markings. The 

 rump is sometimes black, but usually has 

 more or less white markings in the shape 

 of spots and small bars; the white wing- 

 barriug and spotting along the edges of the 

 vanes of the primaries, secondaries, and ter- 

 tials are about equal in number in the two 

 races, but the individual marks are much 

 smaller, as a rule, in americanns. The pattern 

 of the white markings about the head is the 

 same in both forms, but in the present bird 

 these markings are very much less decided 

 than in the northern race. The upper tail- 

 coverts are either unmarked or the markings 

 are very narrow. The barring and streaks on 

 the sides of the breast and flanks are always 

 black and distinct. 



Alascensis. 



White nuchal collar generally very broad and well 

 defined. The upper half of dorsum is almost in- 

 variably thickly and heavily barred with white, 

 which often occupies two-thirds of this area. 

 This is one of the main and most striking differ- 

 ences between the two forms. The lower half 

 of dorsum, although less abundantly marked 

 than the upper half, usually has nbont one-half 

 its surface covered by transverse or longitudi- 

 nal white markings ; in some instances these 

 markings cover nearly the whole back, so that 

 the bird appears to be almost uniformly white 

 on the entire dorsal surface with a faint wavy 

 barring of darker showing indistinctly through 

 the white. The rump is always profusely 

 marked with white bars aud streaks, which 

 extend over the upper tail-coverts, which latter 

 are generally broadly barred and marked with 

 white. The white markings on the wing- 

 feathers have the same distribution as in attier- 

 ieanus, but they occupy nearly twice the area 

 occupied by those in amerieanus, aud in many 

 cases the primaries and secondaries are broadly 

 tipped with white ia the northern birds. The 

 streaks and barring on the sides and flanks are 

 much lighter than in amei-icanus, aud frequently 

 are pale fulvous brown in very narrow bars 

 with broad interspaces of white. 



The following notes form a summary of the characters distinguishing the three American forms 

 of this bird; a series of measurements is appended: 



Amerieanus. — A series of eleven birds from Northern New York have the white markings ot 

 the back in the form of transverse bars, which are frequently restricted to the central p ortions ot 

 the feathers, and in several instances the upper half of the dorsum is very much less marked than 

 the lower portion. The oval or quadrate spots and bars along the webs of the wing-feathers are 

 small. The white line extending from the eye to the nape is very narrow and frequently scarcely 

 discernible. In short, the birds of Eastern North America are darker colored, with the white 

 markings less inclined to spread and become united into broad areas, than is the case in the fol- 

 lowing forms. 



Dorsalis.— The National Museum series of Three-toed Woodpeckers from the Eocky Mountains, 

 ten in number, ranging from Port Kenai and the Southeastern Alaskan coast, and Fort Simpson, 

 on the headwaters of the Mackenzie River, south to Colorado and Arizona, agrees in having a v ell- 

 marked nuchal collar, which is joined by a white stripe from the eye. In all well plum aged sum- 

 mer birds a longitudinal white band begins with the nuchal collar and extends down the back to 

 the rump, with no trace, or at most a very slight one, of transverse barring. This white dorsal 

 band has the same appearance and outline as the white band on the back of the Hairy Wood- 

 pecker, except that on dorsalis this white area extends much higher on the nape "than it does 

 in Picus villosus. The feathers of the rump are usually white tipped. The white quadrate spots 

 and bars on the wing-feathers are smaller than in the birds found farther north, but agree in 

 averaging a little larger than in the birds from Eastern North America. 



