Bird feeder

As a long-term cat owner, I never did this before, but with no cats I decided I need a bird feeder. I didn't sit at my desk very much yesterday so I saw no activity, but today I see visitors out there. Well, one visitor, or a bunch of identical visitors arriving solo. It's dull blue with a little white. I suppose I will learn to identify these birds eventually.

Edited to add: I am told this bird is a chickadee.