On looking at Notts. Uni. peregrines...

Looking at the peregrine pics., it occurred to me that as we have a flat roof on our house extension, would it be an idea to put up some kind of nest site for the likes of (I think) herring gulls?  O.K. I know they're not everyone's cup of tea but as they're in decline, I guess they could do with a bit of help and as we do have quite a lot of them, usually on Sundays when the car-boot sale is on in summer, a flat roof might make a decent nest sight.  We are, however, very high up and have pretty strong winds so keeping a frame in place for pebbles or gravel might be a problem.

  Any thoughts?