Just for fun?
In CGI scenes which merely show huge distances of CGI scenery, landscape or buildings etc, the problem is that nothing moves. To add to the 'realism', it is common to include some flying birds in the distance. And now, when I see a breathtaking CGI landscape scene, I instinctively look for the birds.
My attempts to animate flying birds have been as breathtakingly bad as my attempts to move human figures.
I thought! How about simply processing some 'real' footage of birds. And after wading through lots of youtube clips, I have not found one which contains clear and easily keyed out edges, remain in Frame for more than a few seconds, and have a variety of actions like taking off, flying or gliding.
I am almost resigned to the unlikely nature that such a clip exists. So, I guess it's back to my animated bird; which, at the moment moves like a brick.