70 
BIRDS OF COLORADO. 
295. Callipepia gambeli. Gambel’s Partridge. 
Resident; rare. Known to occur only in south western 
Colorado, where C. F. Morrison shot three of them 40 miles 
southwest of Fort Lewis. Across the line in southern Utah 
and in Arizona they are common. 
297. Dendragapus obscurus. Dusky Grouse. 
Resident; common in the mountains. Its only migration 
is a slight vertical one. Breeds from 7,000 feet to the border of 
timber-line, 4,000 feet higher. At the lower altitude the eggs 
are laid about the middle of May; at timber-line about June i. 
Raises but one brood which is hatched about the middle of 
June. In August they begin to gather into flocks of ten to fif- 
teen individuals and visit the grain fields or the more open 
gulches and foothills for berries. In September they wander 
above timber-line to feed on grasshoppers, reaching 12,500 feet. 
In winter they come down into the thick woods during the 
severest weather, but many remain the whole year close to 
timber-line. 
300b. Bonasa umbellus umbelloides. Gray Ruffed 
Grouse. 
Resident; rare. So rare that the present writer has not 
yet been able to find a hunter who has seen it or even heard of 
it. Occurs mostly farther north, only a few coming as far south 
as Colorado. Is found from 7,000 to 10,000 feet ; breeds among 
the pines just below timber-line and retires to the higher foot- 
hills in fall and winter. 
304. Lagopus leucurus. White-tailed Ptarmigan. 
Resident ; common. One of the most strictly alpine birds ’ 
of the Rocky Mountain region. Fifty years ago the surveying 
parties of the Pacific Railroads found them breeding on the 
Snowy Range, and to-day the tourist who visits the highest 
peaks does not consider he has completed his sight seeing until 
he has been shown a family of Ptarmigan, or “ Mountain Quail 
as they are commonly called. They breed entirely above timber- 
line from 11,500 to 13,500 feet, wandering to the summits of the 
peaks a thousand feet higher. Nesting begins soon after the 
first of June, and the young are hatched the early part of July. 
In southern Colorado eggs have been found as early as the first 
part of May. Only in the severest winter weather do they come 
down into the timber, usually to 10,000 feet, but occasionally to 
8,000. At that season the sexes are in separate flocks and sub- 
sist largely, on willow buds. In the winter they are white, 
changing to the darker mixed color in March and April ; by the 
breeding season in June they have become so close in color to 
