Last year there was a female who was super territorial over the feeder I put out. I would watch her sit in the nearby tree. She would just watch the hummingbird feeder and fly over when another hummer came to scare them off. XD
I put out two feeders this year in the hopes I will get more hummingbirds. =) We'll have to see what happens as I am at a new house so I don't know what their habits are in the area I am in.
@Ven, I think a black-chinned, but I am not positive. It flew away before I could focus my scope on it. I have yet to figure out how to identify female hummingbirds as well.