This video from Texas in the USA says about itself:
Did you know the names of the Anna’s and Rivoli’s Hummingbird are connected? When these species were described in 1829 by French naturalist René Primevère Lesson, he named these dazzling hummers in honor of the Duke of Rivoli and his duchess, Anna de Belle Masséna. Watch a flashy male Anna’s alight on the back right feeder port before a male Rivoli’s steals the spotlight on the back left of the feeder.
Watch live at http://allaboutbirds.org/texashummers for more information about hummingbirds and highlights from the feeders.