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-bro\vn, and 

 measure "62 x '48. Gale found fresh eggs in Boulder 

 CO. between May 20th and June 15th. 



Mountain- Chickadee. Penthesfes gamheli. 



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 ; Gihnan 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 oHve-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 

 supercihum 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 



