Joe F.N. wrote:
Oh, but they have. Here in North America we have had a great come back in Peregrine Falcons, a lot who live entirely in the city because of the rich food source. Sharp-shinned Hawks and Coopers' Hawks are other species who have adapted to urban life as well. 150 years ago there were no skyscrapers, a requirement for Falcons to nest, so it may take a wild species a little longer to evolve entirely to that life style. The Pigeons just happen to adapt a lot quicker.
One of our larger cities purchased a couple pairs of Peregrine Falcons and tried to reintroduce them to the city. They didn't have much success with the adults they purchased but they were able to indoctrinate the chicks and now there are several downtown and they do help control the pigeon population.