ムナジロゴジュウカラ Sitta carolinensis

The largest nuthatch in North America, with distinctive white face, black cap, and blue-gray upperparts. Also note rusty lower belly and undertail coverts. Females have a slightly paler crown than males. Fairly common and widespread, usually in mature woodlands with large trees. Creeps along tree trunks and branches, often upside-down. Sometimes joins mixed flocks with other songbirds. Visits feeders. Listen for insistent yammering calls. Some subtle variation across range, mainly in the darkness of the sides and back, width of the black crown, and vocalizations.