Airbus writes:

You're out on a limb there. There has been A LOT of testing on birds' vision,
and they don't necessarily ask your opinion. . .

Which tests have been done?

Well, I think he made a pretty good "guess" - the GE90-115B tha powers the
777 turns (front fan) at 2550RPM, or 42.5 RPS. He probably didn't ahve to
guess much, as these facts are easily and irrefutably verified.

I obtained the facts from the engine specifications, so no guessing was
required.