Whenever black walnuts are cracked open by mammals, or crushed by vehicles in driveways or highways, many birds eat the highly nutritious meat. In fact, black walnut meat is ranked as a choice food for the eastern towhee, cardinal, white-throated sparrow, brown-headed nuthatch, Carolina chickadee, tufted titmouse, blue jay, and woodpeckers (hairy, red-bellied and downy).
Very informative, Terry!