88 
BIRDS OF COLORADO. 
455a. Myiarchus lawrencei olivascens. Olivaceous Fly- 
catcher. 
Summer visitant; rare, if not accidental. A southern 
species, known from Arizona and Mexico. Taken once by 
Capt. P. M. Thorne, at Fort Lyon, May ii, 1883. (Auk, VI. 1889, 
276.) 
456. Sayornis phoebe. Phcebe. 
Summer visitant; rare. Comes west rarely to the eastern 
edge of Colorado. The only record is the one taken by Capt. 
P. M. Thorne at Fort Lyon, April 20, 1884. (Auk, VI. 1889, 
276.) 
457- Sayornis saya. Say’s Phcebe. 
Summer resident; common. A bird of the plains rather 
than the mountains. Most common along the edge of the foot- 
hills, breeding in towns and around buildings like the eastern 
Phoebe, which it here replaces. Arrives early, from the middle 
of March to the first week in April, according to the season. 
Breeds on the plains and in the mountains to about 8,000 feet. 
Eggs are laid early in June. 
459. Contopus borealis. Olive-sided Flycatcher. 
Summer resident; common. Occurs in migration on the 
plains and in the mountains throughout the State. Breeds 
only in the mountains from 7,000 to 12,000 feet and is much 
less common breeding than in migrations. Breeds at least as 
far south as southern Colorado. Arrives late in May and breeds 
about the last of June. Departs southward in September. 
462. Contopus richardsonii. Western Wood Pewee. 
Summer resident; common. Fairly common throughout 
the State as a breeder below 11,000 feet and very common in 
migration. In some places the most common Flycatcher. Ex- 
tends eastward to Kansas. Arrives last of April and first week 
in May and breeds about the middle of June. It is most common 
during the breeding season from 7,000 feet to the pine region. 
Migrates south in September. 
464. Empidonax difficilis. Western Flycatcher. 
Summer resident; common. Breeds from the plains to 
10,000 feet, but is more common in the upper part of its range. 
Arrives late in May and nests early in July. 
466. Empidonax traillii. Traill’s Flycatcher. 
Summer resident; fairly common. More common on the 
plains, but occurs in the mountains to 8,000 feet, breeding 
throughout its range in Colorado. Arrives early in May and 
leaves late in September. 
