I think this was answered but I am the type that has to ask something multiple times and read the answer even more...
Most of my BIF, maybe 70%, the birds are over 100 yards away, some up to 250-300 yards, it is a limitation of where I shoot. When they are less than 100 yards they are usually Canada Geese or Swans floating around, sometimes they will take to flight, but not that often.
On my 5D IV and 7D II most of the time the bird I am focusing on is not much bigger than the center AF point about the size of the center and the 5 assist points. If I wait for shots where they are frame filling I would get about 2 shots a week and I go out almost every day.
The question is about Animal Eye AF, listening here AE AF will be better when the birds are close enough to lock on the eye it will be better but if a bird is very small in the frame will it be any better than my current gear?
That question being asked, I am keeping my current stable through the winter into spring as I am at about 40k clicks on each camera and haven't had them very long and they work fine...
My R5 needs a repair already. I have NEVER broken something on a camera like this before 


