We always have a swarm of hummingbirds, every year they return the first week of May. Last year quite a few seemed to congregate around a row of "rose of Sharons". It wasn't until clipping the bushes did I realize why. I accidentally clipped a nest they had in the bushes. Now I know what they look like.
Even if you are not an avid bird watcher it is fun to identify these garden visitors. Noting size & shape, color pattern, behavior, and habitat can help. There are books for your region and apps for your phone available to assist.