I've seen ducks above cloud (stratus top 2000ft as far as the eye can see!) so they might have flown through it.
Also in answer to FNG, I recently saw a Canada Goose do a very impressive barrel roll to avoid my Fokker 100 last month. I've also seen a swallow do a very graceful spin, but as it had just bounced off the leading edge of the TB-10 I was flying, I doubt it counts!
spelling!
[ 16 July 2001: Message edited by: Flap40 ]