This video from the USA says about itself:
Female Ruby-throated Hummingbird Visits the West Texas Hummingbird Feeder
9 September 2016
Although Ruby-throated Hummingbirds are uncommon in the west, the cam site in the Davis Mountains has regular visitors every Fall. This visitor was identified by our cam host from West Texas Avian Research as a female Ruby-throated Hummingbird.
In comparison to Black-chinned females, Ruby-throats have overall a cleaner look with cleaner lines: clean white/tan underparts with dark green upper parts, and clear demarcation between dark and clean white throat.
Watch live at http://AllAboutBirds.org/TexasHummers.
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.
For the past 10 years, researchers from West Texas Avian Research have been banding hummingbirds at this site and others throughout the Trans-Pecos region of Texas to study the status and distribution of hummingbirds throughout the poorly known region.