Oh Steve, in our last house we often had pipistrelle bats tangled up in the net curtains! Luckily, I'm not afraid of bats (only spiders).
The chap who owns the house where the seagull was trapped on the roof sent me an update this morning. Apparently, the bird was ringed, and the ring had got caught on a prong of the TV aerial. The RSPCA had to amputate its badly-injured leg, but said that many seagulls can manage on one leg. I think ringing them is a bit dodgy if it causes these mishaps.