331. =Marsh hawk.= CIRCUS HUDSONIUS. Common resident; most common in migration; a few remain throughout winter; breeds on plains, and in mountains to 10,000 feet; in fall may be seen at 14,000 feet.
332. =Sharp-shinned hawk.= ACCIPITER VELOX. Common resident; much more common in mountains than on plains; breeds up to 10,000 feet.
333. COOPER'S HAWK. ACCIPITER COOPERI. Common resident; breeds from plains to 9,000 feet.
334. =American goshawk.= ACCIPITER ATRICAPILLUS. Resident; not uncommon; breeds from 9,000 to 10,000 feet; more common in winter than summer.
334a. =Western goshawk.= ACCIPITER ATRICAPILLUS STRIATULUS. Winter visitor; rare, if not accidental; Pacific Coast form; comes regularly as far east as Idaho.
337a. =Krider's hawk.= BUTEO BOREALIS KRIDERII. Resident; not uncommon; nests on the plains; no certain record for the mountains.
337b. =Western red-tail.= BUTEO BOREALIS CALURUS. Abundant resident; this is the Rocky Mountain form, of which Krider's hawk is the eastern analogue; the ranges of the two forms overlap on the Colorado plains; _calurus_ breeds from plains to 12,000 feet; not a few winter in the State.
337d. =Harlan's hawk.= BUTEO BOREALIS HARLANI. Rare winter visitor; one specimen; natural habitat, Gulf States and lower Mississippi Valley.
339b. =Red-bellied hawk.= BUTEO LINEATUS ELEGANS. Rare migrant; Pacific coast species.
342. =Swainson's hawk.= BUTEO SWAINSONI. Common resident; breeds everywhere below 11,000 feet.
347a. =American rough-legged hawk.= ARCHIBUTEO LAGOPUS SANCTI-JOHANNIS. Somewhat common winter resident; arrives from the north in November and remains till March.
348. =Ferruginous rough-leg.= ARCHIBUTEO FERRUGINEUS. Rather common resident; breeds on plains and in mountains; winters mostly on plains and along lower streams.
349. =Golden eagle.= AQUILA CHRYSAETOS. Resident; common in favorable localities; breeds from foothills to 12,500 feet; in winter on plains and also in mountains, often at 11,000 feet.
352. =Bald eagle.= HALLÆETUS LEUCOCEPHALUS. Fairly common resident; mostly in mountains in summer; on plains in winter.
355. =Prairie falcon.= FALCO MEXICANUS. Not uncommon resident; breeds from plains to 10,000 feet; quite numerous in more open portions of western Colorado.