I once had a friend who called pigeons "rats with wings." I think that it fits. :)

My dad calls the "roof rats" and I think both terms fit really well. I mean, I really like animals, but pigeons are simply dirty and in that special case also stupid... ;)

I've never seen a nest of swallows!

Swallows' nests are little works of art, I think. They are a bit like little caves of sticks and dirt glued beneath overhanging roofs. Like that. Well, actually you cannot see the nest very well in that picture... but it was so cute... :-D