the american tree sparrow (spizella arborea), formerly known as the winter sparrow , is a medium-sized sparrow .
adults have a rusty cap and grey underparts with a small dark spot on the breast .
they have a rusty back with lighter stripes , brown wings with white bars and a slim tail .
their face is grey with a rusty line through the eye .
their flanks are splashed with light brown .
they are similar in appearance to the chipping sparrow .
their breeding habitat is tundra or the northern limits of the boreal forest in alaska and northern canada .
they nest on the ground .
these birds migrate to the united states or southern canada to spend the winter .
usually , chipping sparrows are moving south around the same time as these birds arrive .
these birds forage on the ground or in low bushes , often in flocks when not nesting .
they mainly eat seeds and insects , some berries .
they are commonly seen near feeders with dark-eyed juncos .
this bird's song is a sweet high warble descending in pitch and becoming buzzy near the finish .
