70 BIRDS OF COLORADO. 



295. Callipepla gambeli. Gambel's Partridge. 



Resident; rare. Known to occur only in southwestern 

 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 while, 

 changing to the darker mixed color in March and April ; by the 

 breeding season in June they have become so close in color to 



