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.
Range. - Kowak River, northwest Alaska.
A larger and grayer form of the last species; nesting habits and eggs not differing.
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.
Range. - Eastern half of Canada and northern New England and New York.
These birds were formerly hudsonicus in company with the western ones, but they are now supposed to be a trifle smaller and with the crown duller; this division does not affect the similarity of their habits and eggs.