The amazilias are all in the emerald humming bird group.
I still think this is a rufous tailed emerald hummingbird or rufous tailed amazilia either is correct but technically the latter is mixing its common name with its latin name. Some nice pictures on google
The ZSL hummingbirds are most definitely Amazilia amazilia. In my experience hummingbirds are one of those groups where common names aren't too reliable; like turtles and cichlids, they tend to be a bit fluid.