Don, that reminds me of one of my dad's favourite stories from his time as environmental officer at a British Nuclear Fuels site. They got a call from the factory saying "we've got a couple of pigeons in here - what do we do about it?" As anyone who's worked in a large warehouse-type plant knows, birds often get in through the main doors and there's not much you can do about it. So my dad said to just leave them alone, keep food scraps out of their way, and they'd find their own way out soon enough when they got hungry. Anyway, a couple of weeks later he gets another call from the factory. "OK, we've got rid of the pigeons. Now how do we get rid of the sparrowhawk...?"

Graham.