This a Northern Flicker. It used to be called a "Yellow-shafted Flicker" because the feather shafts are yellow. I suspect that is mainly because no one ever gets a good picture of the bright yellow under the tail! Usually you only see a bright flash of yellow as it flies away! Even the bird books rarely show the underside of the tail! When the bird is perched on a tree, the yellow shafts stand out(sometimes). It interbreeds with the "Red-shafted Flicker" so they were combined taxonomically nomenclaturally. The male has a black "moustache". I was lucky enough to get a series of pics at my feeders to show male and female and also the lovely yellow under the tail!!! All shot from the comfort of home at Streamwood!