Technically I suppose it's more of a side door, but I don't think anyone's written any songs about side doors.
This male Hairy Woodpecker (Picoides villosus) was using the suet feeder at the bookstore door this morning, and I did my best to take a few photos of it through the window.
We usually get woodpeckers (including the Hairy, Downy, Yellow-Bellied Sapsucker, Northern Flicker, and the occasional Pileated) coming to the suet feeder throughout the year, but when the weather starts getting colder they become more frequent visitors.
There are many different commercial suet feeders available in stores, but making your own can be as simple as drilling a few large-bore holes into a length of wood and filling the holes with a homemade suet mix. Recipes for suet mixes can be found online or in books like NatureScape Alberta (available at the Nature Centre). Bob also has some suet recipes on hand, and he'd be happy to tell you what's been working best in our feeder if you drop by the bookstore.