This reminds me of the discussion of the latest 800mm f/5.6E lens a few days back. A guy here on this forum said with a price of $18K, he might as well get TWO of them to put on two different bodies.
If you are one of those people ... you have a lot more choices than a lot of us for sure.
I have the 70-200mm f/2.8G lens. Even zooming it to the 200mm end, I don't think it is long enough for your objective. If I were you, I would be looking at something that can reach 300mm at least, if not 400mm. From there, how fast the lens you can get depends on how big the wallet you have.