black more extended on the throat and the under
parts are grayish of a lighter shade than the upper, the cheeks,
however, remaining white. Their nests are in hollow stubs and the eggs
are indistinguishable from those of the foregoing Chickadees.

738. MOUNTAIN CHICKADEE. _Penthestes gambeli gambeli._

Range.--Rocky Mountain region and west to the Pacific; north to British
Columbia chiefly in higher ranges.

This handsome little Titmouse has a white superciliary line, leaving a
black stripe through the eye. Their habits are like those of the other
Chickadees and they are equally confiding and inquisitive. Their eggs
range from five to eight in number and are either pure white or faintly
marked with reddish brown; size .60 x .45. Data.--Estes Park, Colorado,
June 8, 1803. Nest in an old Sapsucker's hole in a live aspen tree, 28
feet from the ground; cavity lined with hair and fur.

[Illustration 437: 735b--737--738.]
[Illustration: White.]
[Illustration: White.]
[Illustration: right hand margin.]

Page 436

739. ALASKA CHICKADEE. _Penthestes cinctus alascensis._

Range.--Northern Alaska and eastern Siberia.

This bird, which is most like the Hudsonian Chickadee, nests in the
usual manner and its eggs are like those of the common Chickadee of the
east.

740. HUDSONIAN CHICKADEE. _Penthestes hudsonicus hudsonicus._

Range.--Western half of British America.

These brown capped Chickadees are very abundant throughout the northwest
and are even tamer than our United States varieties. They usually make
their nests at low elevations in dead and decayed stumps and line the
bottom of the cavity, which varies from three to eight inches in depth,
with moss and fur. Their eggs, which they lay in May, June or July, are
white, specked with reddish brown and cannot with any certainty be
distinguished from those of the Black-capped Chickadees, the eggs of all
the species showing considerable variations; size .60 x .45.

740a. ACADIAN CHICKADEE. _Penthestes hudsonicus littoralis._

Range.--Kowak River, northwest Alaska.

A larger and grayer form of the last species; nesting habits and eggs
not differing.

740b. COLUMBIAN CHICKADEE. _Penthestes hudsonicus columbianus._

Range.--Rocky Mountains from northern United States to Alaska.

Like _hudsonicus_ but with the crown slaty instead of brownish. No
difference can be distinguished either in their habits or eggs.

740c. CANADIAN CHICKADEE. _Penthestes hudsoni