Humming Birds

My daughter put up her hummingbird feeders a few weeks ago and we have been having a good time watching them. One feeder is close to the table so we get a good close look at them.
I read to figure out how many hummingbirds you have coming to your feeder you should 6x the amount you see at one time at the feeder. That would mean we have about 12 birds visiting.
One is a bully and drives off the others and we frequently have to duck as they zoom past us.