Полевая малая овсянка Spizella pusilla

Small, slender, blank-faced sparrow. Can be either gray or buffy overall, but always note small pink bill, plain face, and thin white eyering. Inhabits overgrown fields and other brushy areas in eastern North America. Often joins flocks of sparrows in winter. Can visit feeders, but less frequently than Chipping or American Tree sparrows. Song is a series of bell-like notes, accelerating like a dropped ping-pong ball.