Hi, sorry for the late reply, I've been inundated with work and have only been getting emails for private messages. I'm not entirely sure my opinion here is relevant or necessary, but I'll share it so long as the replies are non-aggressive. I agree with the building of artificial nest boxes for BOP, namely the peregrine. There have been studies that show the success of peregrines in urban areas, where they actually do better (survive longer, produce more surviving young, etc.) than in natural areas (https://link.springer.com/article/10.1007/s11252-018-0799-x). The link is to a paper by a PHD student, now lecturer, at NTU. I've seen peregrines in natural areas more than I have in urban areas. And that's not to say I'm not looking in the urban areas (because I am). I have only seen evidence of peregrine feeding once in Nottingham. They're not feeding primarily on racing pigeons, they're feeding on urban and feral pigeons. I agree with the building of artificial nest boxes. Why don't you?