About two weeks ago, my neighbour alerted me to a small hole under my lead flashing around my chimney where blue tits were getting into the space (presumably eyeing up a potential nest site). Interesting, at the same time I heard a lot of early morning pecking coming from my loft space but just ignored it. A roofer has now plugged up the hole with new lead flashing. The hole is now completely sealed. Since the roofer visited, I have heard no pecking. However, since the hole was plugged-up blue tits are still eyeing up the non-existent hole - when will blue tits admit defeat and no longer be interested in the now non-existent hole?