Shortly after we moved into our house, my husband came in and said we had the biggest Downy he had ever seen. Of course, what he had seen was a Hairy Woodpecker. The two are remarkably similar.
For comparison, here are the two at the same feeder: (Click to enlarge)
This is the Downy. He is less than half the length of the feeder. Note that his bill is relatively short, about half the length of his head. A goldfinch seems to be interested in watching him.
Compare him to the Hairy:
The Hairy Woodpecker is much larger than the Downy. His length covers more than two-thirds of the feeder. Note the length of his bill. It is almost as long as his head.
Both the Downy and the Hairy do drumming on dead trees to attract mates and establish territory. Our other woodpeckers, the Pileated and (to a lesser extent) the Red-Bellied also drum. The resonance of the drumming is very different from the sound of pecking for insects or excavating a nest cavity. It is a wonderful and welcome sound. No additonal percussion is required.