The two hummingbirds must not like each other.  Once or twice a day I see these two hummingbirds.  One is usually heading for the nectar and then another appears and chases the other away.  I could never figure out whether either make it to the feeder.  One is always in hot pursuit of the other.  Maybe one feeds when the other is asleep.  I just don’t know.  I just get a kick out of watching them chase each other.  Every time.