506 Birds of Colorado 
to the agriculturist in destroying an infinite number 
of insect pests, while the damage they do is infinitesimal. 
They creep and crawl in all sorts of attitudes, often 
hanging suspended from a branch or running along, 
head down and tail up. The note of the bird is recalled 
in its common name, and in this respect the eastern and 
western forms hardly differ at all. 
The nest is placed in an old aspen stub or in a rotten 
pine tree, the hole being usually hollowed out by the 
bird itself; the nest, placed at the bottom of the 
hole, is made of bark strips or moss, and lined with 
fur, hair or feathers; the eggs, four to eight, are dull 
white, rather evenly speckled with reddish-brown, and 
measure “62 x “48. Gale found fresh eggs in Boulder 
co. between May 20th and June 15th. 
Mountain- Chickadee. Penthestes gambeli. 
A.O.U. Checklist no 738—Colorado Records—Allen 72, pp. 161, 
174; Aiken 72, p. 195 ; Trippe 74, p. 230; Henshaw 75, p. 169 ; Scott 
79, p. 92 ; Drew 81, p. 87 ; 85, p. 15 ; Coues 83, p. 240; Allen & Brewster 
83, p. 154; Beckham 85, p. 140; 87, p. 125; W. G. Smith 86, p. 25; 
Morrison 88, p. 72; Kellogg 90, p. 89; Lowe 94, p. 270; Cooke 97, 
pp. 123, 222; Henderson 03, p. 257 ; 09, p. 241 ; Gilman 07, p. 195; 
Warren 08, p. 26; 09, p. 17 ; Rockwell 08, p. 179. 
Description.—Adult—Closely resembling the Long-tailed Chickadee, 
with black crown and throat and olive-grey back, but distinguished 
at once by a conspicuous superciliary stripe running from the forehead 
over and behind the eye ; whole of the back olive-grey with but little 
trace of the buffy on the rump; wings and tail with slightly paler 
edgings, but without white on the coverts; below white, becoming 
olive on the flanks and abdomen ; iris dark brown, bill black, feet 
dusky, blueish-grey in the flesh. Length 5-30; wing 2-80; tail 2-50; 
culmen -38 ; tarsus -65. 
The sexes are alike; the young closely resemble the adults, but 
the black of the crown and throat is duller and less glossy, and the white 
supercilium is less distinct and sometimes rather broken up. 
Distribution.—The mountains of western North America, from 
British Columbia to California and western Texas. In Colorado the 
Mountain-Chickadee is a common resident throughout the year at the 
