White-throated Sparrow - Zonotrichia albicollis
This sparrow was perched on a small pile of sticks and brush. Every few minutes, it would hop inside the pile, grab something, and then come back out on top and eat whatever it had found inside. There was a red squirrel in an adjacent tree that was screaming at this bird. Eventually, the bird left and the squirrel came over and went inside the brush pile...I think it lived in there or at least stored food in there and that the sparrow was stealing from the squirrel's hoard.
Habitat: Forest/meadow edge
Here's the squirrel in its brush pile: