Olive-sided Flycatcher 269 
abdomen and under tail-coverts somewhat less pale; the sides of the 
neck, breast and flanks ashy-brown, indistinctly streaked with darker ; 
w patch of pale yellowish, fluffy feathers on the flanks, generally con- 
cealed but sometimes very clearly visible on either side of the rump ; 
iris brown, bill and legs brownish-black. Length 6-5; wing 4-20; 
tail 2-5; tarsus -55; culmen -85. The sexes are alike, and the young 
essentially like the adults, but the pale tips of the coverts and 
secondaries are brownish. 
Distribution. Breeding throughout the coniferous forest regions 
from Alaska and Hudson Bay southwards to New York and Minnesota, 
and thence along the Alleghanies, Rockies and subsidiary ranges of 
the west to northern Mexico, migrating southwards to Columbia, 
western Ecuador and Peru. 
A fairly common summer resident in the mountains of Colorado, 
but only a migrant in the plains and not so often met with. It is noted 
as a migrant in the plains of Boulder co. by Henderson, and is not very 
abundant in E] Paso co. on the plains, but Scott found it not uncommon 
near Twin Lakes at about 9,300 feet, and Minot at 10,000 feet on Pikes 
Peak. Gale found nests from 8,000 to 9,500 feet in the mountains of 
Boulder co. ; Lowe records it nesting at about 9,500 feet in the Wet 
Mountains in Huerfano co., and Henshaw met with it from 7,000 feet 
to timber line near Fort Garland. In Mesa co. it is stated by Rockwell 
to be quite rare; he only observed it once in Plateau Valley at 6,800 feet. 
It arrives from the south in May; W. G. Smith notes it once at 
Loveland on the 11th; Allen and Brewster first saw it on the 17th; 
Aiken’s earliest record is the 21st. It departs south again at the end 
of August or beginning of September. 
Habits—The Olive-sided Flycatcher is never very 
abundant, possibly owing to its quarrelsome and un- 
sociable nature. Its favourite resort is the top of a bare 
spruce, whence it makes constant sallies after passing 
insects, clicking its bill as it catches them on the wing. 
It has a loud whistle-like call-note, as well as a “‘ Chip, 
chip, chip.” 
The nest is usually saddled far out on the horizontal 
limb of a fir, and is completed about the middle of June ; 
it is small and flat, and appears fragile though constructed 
of strong material. The eggs are generally three in 
number, with a white to pale pinkish ground-colour, 
thickly blotched and spotted with chestnut and purple. 
