The Red Notebook

Around this time of year, I like nothing better than to stand outside at dusk and admire the small local population of bats as they flitter around my head. It really is a wonderful and surprisingly moving experience.

When I say ‘small local population’, I really do mean small. I seldom see more than two or three bats at any one time—unlike my friend Stense, who counted over 60 bats leaving the roost in her attic recently. Stense also has ospreys nesting outside her window. I am consumed with jealousy.

Yesterday evening, I naively decided to try to photograph the local bats as they hunted for insects above my back garden. Well, naive is probably the wrong word as I knew that my efforts were doomed to failure; I was really just being ridiculously optimistic. So I set my camera’s ISO and aperture to maximum and fired away, capturing dozens of photos of empty skies and blurred trees. Bats are fast little buggers.

But I did manage to capture a few images of blurs remotely resembling bats:

A bat flittering above my back garden last night.

Yes, I know the photos are crap, but I rather like their ethereal, crepuscular nature—which pretty much sums up bats, as far as I’m concerned.

I just stood out in my garden with the first bat of the summer circling my head.

Utterly magical.

• Click bats fly by my window
• The evolution of echolocation in bats

BBC: Bat fossil solves evolution poser

A fossil found in Wyoming has resolved a long-standing question about when bats gained their sonar-like ability to navigate and locate food.

They found that flight came first, and only then did bats develop echolocation to track and trap their prey.

A large number of experts had previously thought this happened the other way around.

To me, it seems obvious (always a dangerous word when talking about evolution) that bats must have been able to fly before they evolved echolocation. Echolocation would seem to have only limited use for ground-based mammals, otherwise more mammals would surely have evolved the capability.

I was curious to know, therefore, why so many experts thought that bats’ echolocation must have evolved before flight. I thought it might be because, according to the above BBC article, all bats echolocate, so, unless echolocation evolved independently several times over (which is perfectly possible), it must have evolved in a (presumably early) common ancestor. It turns out that that there was simpler explanation as to why so many experts believed echolocation evolved before flight: until this new fossil, Onychonycteris finneyi, was discovered, another species, Icaronycteris index, had, for over 40 years, been regarded as the oldest known bat—and Icaronycteris index could echolocate.

I was also surprised to learn that all bats echolocate. I had assumed that fruit bats don’t. It turns out they do have the capability, but it is greatly reduced—as is also the case with vampire bats. Echolocation in these bats, it seems, could be seen as vestigial, and might be on the way out.

Interesting stuff.

I like bats.

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.