Listen mate. It's easy to identify BOP to carry out what as to be done, unless you are total dimwit. As for having rollers, again if you have a resident pair or a few pairs of PF around you then it will be hard. As for witnessing a strike, trust me it is painful if you own pigeons, but again if you don't it will proberly be exciting. Trouble is there are too many of the poxy things in this country and they need to be dealt with.