"Grouse and ducks tend to tumble too, but that's for an entirely different reason"
Yup they're usually full of buckshot.
Seem to recall watching Rooks (or Ravens) looping & rolling while soaring the hangers in Goose Bay - maybe it was too much Screech though
Had a Buzzard spin while it was soaring alongside me once in a strong thermal - we were both watching each other but I was (deliberatly) slowing down to see how slow it would go. Said bird lowered full flap & wobbled a bit then departed rapidly leaving loads of feathers in it's wake
