148 Birds of Colorado 
on a specially selected spot—a log or flat rock generally. 
The sound is caused by the rapid vibration of the wings, 
and is sometimes kept up for hours and resembles the 
sound of a kettle-drum. It is only indulged in by the 
male, and is a love-call to attract the female. 
Genus LAGOPUS. 
No crest, ruff or tufts; only a naked comb over the eye ; tail short, 
about 2 of wing, of fourteen rectrices nearly covered up by the coverts ; 
tarsi and toes densely feathered to the claws ; plumage white in winter. 
A considerable genus containing three well-marked North American 
and three well-marked European species, as well as a good many less 
well-defined species and subspecies, all restricted to the boreal zone. 
White-tailed Ptarmigan. Lagopus leucurus. 
A.O.U Checklist no 304—Colorado Records—Baird 58, p. 636; 
Allen 72, p. 164; Aiken 72, p. 209; Batty 74, p. 390; Coues & Trippe 
74, p. 426; Brewer 74, p. 348 ; Henshaw 75, p. 438; Coues 76, p. 263 ; 
Scott 79, p. 96; Drew, 81, p. 141; 84, p. 392; 85, p. 17; Morrison 
89, p.181 ; Kellogg 90, p. 87; Bendire 92, p. 83 ; McGregor 97, p. 38; 
Cooke 97, pp. 70, 202; Warren 00, p. 169; 08, p. 20; Osgood 01, 
p- 180; Henderson 03, p. 235; 09, p. 228; Henshaw 05, p. 315; 
Judd 05, p. 47. 
Description.—In summer—Above, including the head, fore-neck and 
breast, mottled, barred and spotted with black, white and tawny ; 
tail, wings, belly and legs white, sometimes yellowish and discoloured, 
the white of the tail partially hidden by the long coverts; iris hazel, 
comb over the eye red, bill black. Length 12-0; wing 6-75; tail 4-5; 
bill -37; tarsus 1-20. 
In late summer after the post-nuptial moult, the dark parts are 
more uniformly grey with finer markings; in winter pure white 
throughout. The moults take some little time to complete, so that 
specimens in every intermediate stage are frequently met with (see 
Plate 3). 
Distribution.—The Rocky Mountains at high elevations, chiefly above 
timber line, from British Columbia south to the Cascade range in 
Oregon and the Taos range in New Mexico. 
This Ptarmigan is fairly abundant throughout the higher mountain 
ranges of Colorado, and is a resident there all through the year. It 
breeds above timber line from about 11,500 feet to the summits of the 
mountains, while in winter it stays about timber line though sometimes 
driven down to lower levels, perhaps 9,000 feet, by heavy storms. It 
