The chap from the Barn Owl Trust has called to check our owl box and see if it's inhabited. There are owls around, but I don't know if that's where they live.
I went, a few months back, to an information day about church maintenance - I learned a lot about gutters and drainage - the general principle is that if you keep your gutters and drainpipes in good nick, that's most of the repairs saved, except major structural ones, and many of them are caused by water in the wrong place anyway. Most of the questions were about bats in churches. Their droppings are very acidic and can damage, for example, marble monuments and wooden furniture, and pews have to be kept covered apart from service times, too or else people will sit on batshit and be displeased.
A local church (not in our village) has a big problem with bats - they are protected, of course, so nothing can be done to risk injuring them. Apparently, it started when the big house (the Old Rectory, in fact) next to the church caught fire. The bats had lived in the attics and, displaced, they moved into the church. They hadn't lived at the Old Rectory that long, in fact. A barn in the next field had been converted into a house. It seems that this left the bats homeless, until they found a new place to live...
There are a lot of bats about here, and I like them very much. Occasionally, one will get into the house. Of course, they can avoid you and there's no risk of being divebombed, but they are very small and impossible to catch and creep into the tiniest of cracks behind furniture, so it's hard to get it out again.
Anyway, about the bats in churches. One person said they had found the answer. They left the lights on overnight for a few weeks. This didn't harm the bats, but they didn't like it much, so they moved out. Once they had found somewhere else to live, the lights could be left off again.
Report back on the owls. A startled tawny owl flew out, but it was just sleeping there rather than nesting. There are pellets around, so it's evidently a regular roost. They were quite encouraged by this, as it's the first owl they have come across today after a morning of box-visiting.