It's been empty for several years - the entrance is quite small and therefore limits the type of bird that can use it. No Steller's jays, or pigeons here, thank you.
Well, we have a lot of Mountain Chickadees here. They love the trees with all the pine seeds and insects, their principal diet. They are hard to spot if you don't know them as they have a habit of perching in the trees where they just whistle at you. It sounds a little like "We're in the money!" A very cheerful sound.