The last several days, I have been watching two non-male hummingbirds
which I believe are immatures. There is a great deal of interaction
between the two, including soaring and swooping in parallel, like the
Rockettes or synchronized swimmers. What comes to my mind are two kids
playing. Has anyone else observed anything like this, and/or is there
anything in the literature? All I am aware of is swallows playing with
feathers, which I see as different, bird to inanimate object.