BIRDS OF NORTH AND MIDDLE AMERICA 155 



KEY TO THE FORMS OF BONASA UMBELLUS (LINNAEUS) 



a. General coloration more brownish than grayish. 

 b. Dark-brown ventral barring pronounced. 



c. General coloration very dark (chestnut to dark auburn). 



d. General coloration distinctly brownish with little or no grayish cast. 

 e. Very reddish, back bright argus brown to dark chestnut, tail auburn 



to bay (Olympic Peninsula) Bonasa umbellus castanea (p. 169) 



ee. Duller and less reddish, back between Front's brown and Dresden 

 brown; tail dull ochraceous-umber (brown phase) (Vancouver Island). 



Bonasa umbellus brunnescens (p. 170) 



dd. General coloration with more grayish or dusky appearance; tail argus 



brown to cinnamon-brown (w. slopes of Rocky Mountains, Idaho, to 



ne. Washington) Bonasa umbellus phaia (brown phase) (p. 178) 



cc. General coloration lighter (sayal brown to argus brown). 

 d. Distinctly brownish with little or no grayish cast. 



c. Ventral barring darker — cinnamon-brown to dark mummy brown (sw. 

 British Columbia to nw. California) Bonasa umbellus sabini (p. 166) 

 ee. Ventral barring lighter — dusky isabelline to buckthorn brown (Appala- 

 chian Mountains from ne. Pennsylvania to Georgia). 



Bonasa umbellus monticola (p. 163) 

 dd. Browns mixed with some gray. 



e. Blackish areas of ui)perparts more pronounced ; brown parts darker and 

 less rufescent — cinnamon-brown to dark Front's brown (n. New 

 England, Nova Scotia, w. to s. Ontario). 



Bonasa umbellus togata (p. 171) 

 ee. Blackish areas of upperparts less well developed, brown areas paler 

 and more rufescent — Mikado brown to snuff brown (nc. British 

 Columbia s. to ne. Oregon). 



Bonasa umbellus affinis (brown phase) (p. 175) 

 bb. Light brown, barring less pronounced. 



c. General coloration darker, head and neck with little if any grayish suf- 

 fusion, tail (brown phase) nearly hazel (s. New England, e. New York, 



s. to District of Columbia) Bonasa umbellus umbellus (p. 156) 



cc. General coloration paler, head and neck with pale grayish suffusion, tail 

 (brown phase) nearly ochraceous-tawny (sw. Michigan s. to c. Arkansas). 



Bonasa umbellus mediana (p. 161) 

 la. General coloration more grayish than brownish. 

 b. Definitely gray, with little or no brownish wash. 

 c. Very pale (smoke gray to pale neutral gray). 

 d. Tarsus un feathered'^" for one-quarter its length or less ; more white In 

 upperparts (w. Alaska to n. Alberta). 



Bonasa umbellus yukonensis (p. 182) 

 dd. Tarsus unfeathered"' for not less than half its length; less white in 

 upperparts (c. Utah, se. Idaho, to ne. North Dakota). 



Bonasa umbellus incana (p. 179) 

 cc. Darker (mouse gray to light grayish olive) (w. slope of Rocky Mountains, 

 Idaho, to ne. Washington) . .Bonasa umbellus phaia (gray phase) (p. 178) 

 bb. Gray mixed with considerable brown. 



c. Tarsus unfeathered for more than half Its length (nc. British Columbia 

 to ne. Oregon) Bonasa umbellus affinis (gray phase) (p. 175) 



^^ Point of Insertion of feathers on outside of tarsus to junction of tarsus with 

 middle toe is measurement for unfeathered tarsus. 



