Chestnut-backed Chickadee
Poecile rufescens
It is a small chickadee, 11.5–12.5 cm (4.5–4.9 in) long with a weight of 8.5–12.6 g (0.30–0.44 oz). The head is dark blackish-brown with white cheeks, the mantle is bright rufous-brown, the wing feathers are dark gray with paler fringes. The underparts are white to pale grayish-white, with rufous or pale gray flanks. It is often considered the most vibrant of all chickadees. Joseph Grinnell was one of the first to provide a significantly detailed description of this variation. Voice: Chestnut-backed chickadees can be identified by their “chick-a-dee” call, with “dee” repeated a few times. Adults and older nestlings can also be identified by their hissing noise, which mimics a snake while protecting their nests. They rarely use their “gargle” calls.
ID text from Wikipedia, CC BY-SA 4.0

Marsh Tit
Poecile palustris
The nominate subspecies has a black cap and nape with a blue sheen visible at close quarters. The black 'bib' below the bill is rather small; the cheeks are white, turning dusky brown on the ear coverts. The upperparts, tail and wings are greyish-brown, with slightly paler fringes to the tertials. The underparts are off-white with a buff or brown tinge strongest on the flanks and undertail coverts. The bill is black and the legs dark grey.
ID text from Wikipedia, CC BY-SA 4.0

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Play today's Daily BirdPhotos and recordings are credited to their authors under the licence shown. Full profiles: Chestnut-backed Chickadee and Marsh Tit.