It looks like a hummingbird and it acts like a hummingbird, but it's a butterfly or a moth. I took the photo in Croatia, but the insect is distributed all over Europe, as long as it's warm.
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/109661044@N07">Rob Schleiffert</a> from Holland
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/109661044@N07/20201932532/">Hummingbird hawk-moth</a>