We have had three Ruby Throated Hummingbirds at our feeder from dawn until dusk. Two females and a male. The females don't have the ruby throat. Sometimes they are all there at once. They dart at  each other as if to chase one another from the feeder. They empty the feeder in about three days. One of our theories was that the females are feeding their young. I am awakened each morning about 5 AM with a load hum outside the window. Notice the sugar water is clear. It's an old wives tale that it must be red.