This video from the USA says about itself:
6 September 2017
Four Rivoli’s Hummingbirds stopped by West Texas in under 5 minutes this morning! The two adult males, juvenile male, and female all sipped from the same port on the back left of the feeder, providing us with a great chance to compare plumages within the species. Check it out!
Adult males: Blackish, dark green bodies, brilliant teal gorget and purple crown
Immature male: scaled appearance, light green back, iridescent green splotch on throat
Adult female: bold white spot behind the eye, white-gray throat, gray flanks, green back
The West Texas Hummingbird Feeder Cam is nestled in the mountains outside Fort Davis, Texas, at an elevation of over 6200 feet. This site hosts a total of 24 Perky Pet Grand Master hummingbird feeders, and during peak migration can attract hundreds of hummingbirds from a dozen species that are migrating through the arid mountains.