its highest
range as on the plains; early spring arrival; a few winter in the State.

418. =Poor-will.= PHALAENOPTILUS NUTTALLII. Common summer resident;
breeds from plains to 8,000 feet; has been noted up to 10,000 feet.

418a. =Frosted poor-will.= PHALAENOPTILUS NUTTALLII NITIDUS. Rare summer
resident; few typical _nitidus_ taken; a more southern variety.

420a. =Western nighthawk.= CHORDEILES VIRGINIANUS HENRYI. Abundant
summer resident; breeds on the plains and up to about 11,000 feet; in
fall ranges up to 12,000 feet; most common on plains and in foothills.

422. =Black swift.= CYPSELOIDES NIGER BOREALIS. Summer 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 inaccessible 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 ALEXANDRI. Summer resident;
local; only in southwestern part of the State, and below 6,000 feet.

432. =Broad-tailed humming-bird.= SELASPHORUS PLATYCERCUS. Common summer
resident; Colorado's most common hummer; breeds from foothills to 11,000
feet; ranges 2,000 feet above timber-line in summer.

433. =Rufous humming-bird.= SELASPHORUS RUFUS. Summer resident; local; a
western species, coming into southwestern 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.

436. =Calliope humming-bird.= STELLULA CALLIOPE. Summer visitor; rare or
accidental; but two records, one near Breckenridge at an altitude of
9,500 feet; western species.

443. =Scissor-tailed flycatcher.= MILVULUS FORFICATUS. Summer visitor;
rare or accidental; but one record; southern range, and more eastern.

444. =Kingbird.= TYRANNUS TYRANNUS. Common summer resident; occurs only
on plains and in foothills up to 6,000 feet; same form as the eastern
kingbird.

447. =Arkansas kingbird.= TYRANNUS VERTICALIS. Common summer resident;
more common in eastern than western part of the State; fond of the
plains and foothills, yet breeds as high as 8,000 feet.

448. =Cassin's kingbird.= TYRANNUS VOCIFERANS. Common summer resident;
breeds on plains and up to 9,000 feet in mountains; occurs throughout
the State.

454. =Ash-throated flycatcher.= MYIARCHUS CINERASCENS. Rare summer
resident;