BIRDS OF NORTH AND MIDDLE AMERICA 69 



KEY TO THE FORMS (aDULTS) OF DENDRAGAPUS OBSCURUS (SAY) 



a. Top of head, nape, and interscapulars uniform, unbarred (males). 

 b. Rectrices usually with no grayish terminal band (or terminal band very 

 dark, not conspicuously different from rest of rectrices). 

 r. Under tail coverts blackish tipped wfith white (s. Yukon to Idaho and nw. 



Wyoming) Dendragapus obscurus richardsonii (p. 82) 



cc. Under tail coverts grayish chaetura drab tipped with white (mountains of 

 e. Washington, ne. Oregon, se. to c. Nevada). 



Dendragapus obscurus pallidus (p. 88) 

 bb. Rectrices with a distinct grayish terminal band. 



c. Terminal gray band on tail broader (20-35 mm. broad) . 



d. Tail longer (average 189 mm.) (coniferous forests Kern to Calaveras 



Counties, CaUf.) Dendragapus obscurus howardi (p. 80) 



dd. Tail shorter (average 170 mm.). 



e. Terminal band much speckled with black (sc. Washington to ne. Cali- 

 fornia and w. Nevada) Dendragapus obscurus sierrae (p. 77) 



ee. Terminal band not or only slightly speckled with black (Rocky Mountains 

 from s. Alontana to n. Arizona and wc. New Mexico). 



Dendragapus obscurus obscurus (p. 85) 

 cc. Terminal gray band on tail averaging narrower (15-22 mm. broad) (moun- 

 tains of extreme w. North America from sw. Yukon to nw. California) . 



Dendragapus obscurus fuliginosus (p. 74) 

 (islands and coast of se. Alaska to Queen Charlotte Islands). 



Dendragapus obscurus sitkensis (p. 70) 

 aa. Top of head, nape, and interscapulars barred (females). 

 b. Rectrices with no distinct grayish terminal band. 



c. Under tail coverts dark fuscous tipped with white (s. Yukon to Idaho and 



nw. Wyoming) Dendragapus obscurus richardsonii (p. 82) 



cc. Under tail coverts grayish banded with chaetura drab and tipped with white, 

 (mountains of e. Washington, ne. Oregon, se. to c. Nevada). 



Dendragapus obscurus pallidus (p. 88) 

 bb. Rectrices with a distinct grayish terminal band. 

 c. Terminal gray band on tail broader (20-35 mm.). 

 d. Tail longer (average 153 mm.) (coniferous forests Kern to Calaveras 



Counties, Calif.) Dendragapus obscurus howardi (p. 80) 



dd. Tail shorter (average 144 mm. or less). 



e. Sides and flanks with conspicuous white marks (Rocky ^fountains from 

 s. Montana to n. Arizona and wc. New Mexico). 



Dendragapus obscurus obscurus (p. 85) 

 ee. Sides and flanks with no or little white (sc. Washington to ne. California 



and w. Nevada) Dendragapus obscurus sierrae (p. 77) 



cc. Terminal gray band on tail narrower (10-20 mm. broad). 



d. Upperparts with a distinct rufescent tone (islands and coast of se. Alaska 

 to Queen Charlotte Islands). 



Dendragapus obscurus sitkensis (p. 70) 

 dd. Upperparts not distinctly rufescent, but grayish (mountains of extreme 

 w. North America from sw. Yukon to nw. California). 



Dendragapus obscurus fuliginosus (p. 74) 



653008°— 46- 



