Black capped chickadees band together in small, stable groups. Likely all those beady, active pairs of chickadee eyes offer some survival advantage.
Our feeder is about 20' in front of the house. Several years ago I noticed I could walk outside when the feeder was empty and not hear or see a chickadee. But walk towards the feeder and the band would instantly materialize in chickadee-dee-deeing mass anticipating a feeder refill. This year they added a new twist. If I am out on the property when the feeder is empty (and only when empty), one or two of the chickadees will land nearby, sometimes within a few feet and chatter away. Now they could just be updating me on chickadee current events, but my suspicions are that they are berating me for my sloth in letting the feeder run empty.