CHECK-LIST OF COLORADO BIRDS 327 



almost as plentiful at its highest range as on the plains ; 

 early spring arrival ; a few winter in the State. 



418. Poor-will. Phal.enoptilus nuttallii. Common 

 summer resident; breeds from plains to 8,000 feet; has 

 been noted up to 10,000 feet. 



418a. Frosted poor-will. Phal.enoptilus nuttallii 

 NiTiDUS. Rare summer resident ; few typical mtidus taken ; 

 a more southern variety. 



420a. Western nighthawk. Chordeiles virginianus 

 HENRYi. Abundant sununer resident ; breeds on the plains 

 and up to about 11,000 feet; in tall ranges up to 12,000 

 feet ; most common on plains and in foothills. 



422. Black swift. Cvpseloides Niger borealis. Sum- 

 mer resident ; abundant locally ; southwestern part of the 

 State; breeds from 10,000 to 12.000 feet, and ranges up 



to 13,000 feet. 



425. White-throated swift. Aeronautes melanoleucus. 

 Summer resident ; not uncommon locally ; breeds in inac- 

 cessible rocks from 6,000 to 12,000 feet, if not higher; 

 most common in southern part of the State. 



429. Black-chinned humming-bird. Trochilus alexan- 

 DRi. Summer resident ; local ; only in southwestern part 

 of the State, and below 6,000 feet. 



432. Broad-tailed humming-bird. Selasphorus platy- 

 CERCUS. Common summer resident ; Colorado's most com- 

 mon hummer ; breeds from foothills to 1 1 ,000 feet ; ranges 

 2,000 feet above timber-line in summer. 



' 433. Rufous humming-bird. Selasphorus rufus. Sum- 

 mer resident ; local ; a western species, coming into south- 

 western Colorado, where it breeds from 7,000 to 10,000 

 feet, and ranges in summer several thousand feet higher ; 

 a few records east of the range. 



