Arthur Cleveland Bent, Life histories of North American woodpeckers (1939)
“ And these associations seem to be actual and usual, and not temporary and accidental ones as they are between most birds of different species. The downy woodpeckers are peaceable little fellows but other birds will impose on them. I have seen a yellow-bellied sapsucker and a mob of three or four English Sparrows near Pine Bluff chasing one about. But downy was a fast flier and outflew all his tormentors each time. Their flight is undulating and typical of the woodpecker family. ”
