346 University of California Publications in Zoology  [Vou. 24

the darker color and the lack of rusty markings dorsally and on the
wings, as compared with southern specimens, is constant and con-
spicuous. The northern adult differs in measurements and proportions
from any southern skin.

Nuttallornis borealis (Swainson). Olive-sided Flycatcher

Not common, but occurring as scattered pairs throughout the low-
lands. Present when we arrived, the last week in May. Last bird
seen September 2. One specimen collected (no. 42181).

Myiochanes richardsoni richardsoni (Swainson).
Western Wood Pewee

Common in the lowlands, usually about clearings. On our first
day in the field, May 27, wood pewees were fairly numerous. The last
was seen September 4. Six specimens collected, all breeding adults
(nos. 42182-42187).

Empidonax trailli alncrum Brewster. Alder Flycatcher

An inhabitant of willow thickets in lowland swamps. Not common,
and so shy that the species could easily be overlooked were it not for
the call note. First arrival noted June 5; last bird seen August 24.
Five specimens collected (nos. 42188-42192), three adult males, and
two males in first winter plumage.

Empidonax hammondi (Xantus). . Hammond Flyeatcher

Abundant in the poplar woods of the lowlands. Present in numbers
when we arrived, the last week in May, and almost up to the time of
our departure. Early in September there was a marked diminution
in numbers, but a few Hammond flycatchers appeared at intervals
up to September 21, when the last one seen was collected. Ten speci-
mens taken (nos. 42193-42202).

A nest (no. 1852) taken near Hazelton, June 16, contained two
fresh eggs, probably an incomplete set. It is constructed outwardly
of ‘cotton’ from the fireweed, and some plant fiber, and moss; the
Jining is of feathers and eattle hair.

A second nest (no. 1853), taken in Kispiox Valley, July 7, eon-
tained three slightly incubated eggs, a complete set. It was in a willow
thicket at the edge of a small stream, about twenty feet from the