I actually pitched a game at the start of the year in which a big component was flocking movement. I used this exact video! It was a big inspiration (also, filmed on the river Shannon which isn't *too far from where I grew up in Ireland). Some great starling shots in the Tree of Life if you haven't seen it, and Winged Migration is a film that would probably be a good touchstone too.
Definitely voting for this, for feel and the possible art. Love it. Lots of interesting directions to take it. I still want to return to my somewhat related game concept in my spare time once I finish some other projects, so this makes me wistful.
Good luck Greg!