Bird lore - Project Puffin

Notes on the Plumage of North American Birds 17
(3) Yukon Chickadee {P. a. turneri). A large form, paler even than the Long-
tailed Chickadee, which inhabits northern and western Alaska,
Carolina Chickadee {Penthestes carolinensis carolinensis. Fig. 5).
Although this species so closely resembles the Black-capped Chickadee that it
might well be considered merely a race of it, the two kinds do not intergrade.
During the winter they may both be found in a narrow strip of territory at the
northern limit of the range of the southern species and the southern limit of
the range of the northern species. Under these circumstances, it requires a
highly trained eye to distinguish these birds by the slight difference in their
size and markings, the Carolina Chickadee being smaller and without whitish
margins to the wing-coverts; but to one familiar with their notes field identi-
fication is possible.
Two races of the Carolina Chickadee are known: (i) the Florida Chickadee
{Penthestes carolinensis itnpiger), a small, dark form from east-central Florida,
and (2) the Plumbeous Chickadee (P. c. agilis), a larger, paler form from the
western part of the lower Mississippi Valley.
Mexican Chickadee {Penthestes sdateri. Fig 3). This, the most southern-
of the Chickadees, may be known by its dark gray, sides and large black throat
patch. No races of it have been described.
Mountain Chickadee {Penthestes gamheli gambeli. Fig. 6). The white
line over the eye at once distinguishes this Chickadee, of which one race is
known, Bailey's Mountain Chickadee {Penthestes gambeli baileyce), of the
"mountains of the great Basin region and northern Lower California,
Alaska Chickadee {Penthestes cinctus alascensis. Fig. i). This is an
Alaskan form of a Siberian species, which resembles the Hudsonian Chickadee,
but is paler and has the sides of white instead of gray.
Acadian Chickadee {Penthestes hudsonicus littoraUs. Fig. 2). This species
may be known by its brown crown, brownish back, and rusty sides, which are
evident in the field. In the interior of Canada and northwest to Alaska, it is
replaced by the closely allied Hudsonian Chickadee {Penthestes hudsonicus
hudsonicus) , a larger, somewhat more brightly colored race.
Chestnut-backed Chickadee {Penthestes rufescens. Fig. 7). This distin-
guishing character of this species is expressed in its common name. As stated
by Professor Cooke on the preceding page, four forms of it are known of
which the California Chickadee {Penthestes rufescens neglectus), has only a
tinge of rusty on the flanks, and Barlow's Chickadee {P. r. harlowi), has no
rusty on the flanks.