If so, where?
(Inspired by the “Rarest animal you’ve ever seen” thread.)
You might want to PM Colibri 
I don’t know of any, there are of course captive ones (e.g. at Blackburn Pavilion in London Zoo) but wild ones, I doubt it - they need the right kinds of flowers, don’t they?
And where the sorta-right kind of flowers do occur, they’d have natural competition. Either from Hawkmoths, Sunbirds or similar.
No species of hummingbird has been introduced to and established a population anywhere in the wild in the Old World.
That’s correct. There are no introduced populations of hummingbirds outside of their natural range in the Americas.
Hummingbirds are flexible in their choice of flowers, and there are plenty of flowers adapted to bird pollination in the Old World (pollinated by hummingbirds’ ecological equivalents like sunbirds or honeyeaters). Given hummingbirds’ superior flight capabilities, they might well out-compete other nectarivores.
Thanks, guys.
You say “superior”, the sunbird says “wasteful” …
And here based on your user handle I thought you might be discussing another bird group…
