How Many Hummingbirds?

I spent a good portion of my Saturday tending to the yard, feeders, bird baths and other tasks. Unlike earlier Saturdays this summer I had the luxury of seeing Ruby Throated Hummingbirds frequently, for many hours. While I have been observing them closely, I can't quite determine how many individuals are working the four nectar feeders. It is at least three, I'm decided. One female who preferentially perches in the south side trees, one male who seems to be based in the same area, and one female who most often perches on the opposite side of the house. If "exit path" is an indicator I could have as many as five, but I am skeptical. Hummingbirds move about, and I could even be getting some "neighbor" birds on patrol. Real professionals would catch and band the birds. But I am inclined to leave them in peace. It's really enough to know there are birds who stay with me for the summer.