The answer to your question "Why don't you" I do agree with nest boxes being erected for some BOP ie. Owls which there is now a distinct decline in thier population.I DO NOT agree with nesting sites for Peregrines and such like,they are not an endangered species and are adding to the demise of other wild birds.You say you've only seen peregrines at the NTU feeding once,so I'll be able to enlighten you a little,I watch them on a regular basis during breeding time and I can assure you they feed mainly on racing pigeons and don't let anyone advise you otherwise,ferral pigeons are what's known as street wise and very rarely hunt for food above house top level and do not exerciese like racing pigeons thus evading BOP.