As self loading freight carried in and out of Bristol, I do wonder whether your post underlines the concerns raised by some posting here.
It has been suggested by some with a better technical understanding than me, that the likely reason that the aircraft shown in the video made full use of the limited runway at Bristol was because it was using reduced thrust.
If a decision had to be made on this aircraft to delay the rotate call to avoid a large flock of birds crossing the runway, what would have been the consequence?