There are two different collective nouns for bats (by which I mean the nocturnal mammals): a colony and a cloud. Both nouns seem a bit excessive when it comes to the number of bats that flitter about our garden on summer evenings. Last year we had four; this year we have three. Carry on at this rate, and next year the most appropriate collective noun will be a brace.
My partner Jen and I are thrilled to have bats in our garden. As soon as we spot one flying past the window on its crepuscular jaunts, we call out "Bats!" and rush on to the patio to watch them. It is a totally magical experience.
Watching bats is the sensual equivalent of culture shock: we and the bats perceive the world in totally different ways. If we stand still for a few seconds, the bats seem to assume we are inanimate objects and happily fly about our heads, apparently oblivious to the fact that we are large mammals that might constitute a danger to them. To us, the bats fly by totally silently, whereas, from the bats' point of view—or should that be point of listen?—they are making such a racket of clicks to assist with their echolocation system that they temporarily have to disconnect their auditory bones (or ossicles) during each click to avoid deafening themselves. We cannot begin to imagine how bats perceive the world.
So mesmerised was I by the bats on Friday evening that I didn't realise I had rushed out on to the patio without any shoes on. Until, that is, I felt the unique squishing sensation that comes from standing on a slug in your socks.