Seeking advice on feeders for the daycare

My Ramona spends half a day at the campus daycare. Her teacher is interested in placing a couple of feeders outside the classroom window to attract birds for the toddlers to watch. Any suggestions on the best kinds of feeders for the birds they're likely to get on that end of campus? Thoughts on who might turn up? The teacher thinks she's seen woodpeckers in the courtyard, and there are a bunch of beautiful old firs just behind the compound. I'm planning on doing a classic posterboard display of likely birds to post near the window. I've seen juncos, house finches, and a Northern flicker on the grounds in the past.