Nice . . . a bit dangerous to fly to them, but birds aren't too bad at avoiding drones (unless they want to attack one !).
They sure avoid each other well in such a tight flock.
They look like Starlings, very common for them to fly like that to prevent predator attack.
I googled Mallorca Spain Starlings to see if they were found there, and yes it seems they migrate through.
This link came up too, incredible flight patterns, and shows how good they are at flying in formation avoiding each other.
Those are murmurations - large flocks of birds that swarm together, usually just before roosting for the night. It's usually a group of Starlings, though other birds do it too. They resemble schools of fish in the way the move. It's not understood exactly what they're up to, but they're fascinating to watch. You were fortunate to see them. Nice job with the flying and the video.
That’s a spectacular view of a murmuration. They are pretty common with starlings, as said above, the main participants. Only a drone could really capture this phenomenon and it really does look dramatic. These days you have to consider the impact on the birds but as said above they are extremely adept at avoiding each other and ergo presumably other flying objects. Will be interesting to see what other Forum members think.