Bats behaving bizarrely

[Squiff70]

Any bat experts on MN?

We live on a suburban housing estate. Delighted to say we share our neighbourhood with some bats (also batty people but that's for another thread). Pipistrelles, I think.

Sometimes at dusk or after dark, if I stand at the kitchen window overlooking the back garden, I see bats, but they are doing something strange that I can't think of an explanation for. I'll explain, but don't call a psychiatrist okay? I'm fine twitch

These bats fly directly towards the kitchen window, one at a time but in a line, almost like they are queueing up and taking turns. At the last second, they swerve to avoid hitting the window and then the next bat approaches within a couple of seconds. I am 100% certain it's a group of bats and not just one who's been eating too many fermenting apples.

I am fully aware that bats have extremely poor eyesight (if any) and rely on sonar for navigation and built-in anti-collision technology, so I don't think they're seeing their reflections in the window like birds would. It's the queuing in a line and taking it in turns which had utterly baffled me.

Can anyone come up with any theories for this behaviour? I'm not drunk either (8 months pregnant and definitely not been hitting the bottle!).

could they be hunting bugs attracted to the light from the kitchen window?

No, because the light wasn't on during watching this or I wouldn't have been able to see them. The house was dark.

Young bats do practise entering the roost, and some species do fly in and out of the roost a few times before going out for the night. We’re still quite early in maternity season though, possibly too early for the young to be flying yet. Any chance you could film it? Might give us more of an idea.

Their eyesight isn’t actually that bad, but flying at night means far fewer predators around.

This too!

Thank you for explaining this. I do confess this isn't behaviour I have witnessed recently. It has happened in previous years on many many occasions which I unintentionally omitted from my OP. I can't remember where in the season we were at those times but definitely the summer months.

I'll keep an eye out for it happening again but don't think I'd be able to capture it on film without specialised equipment. At these times I've had the lights off (no lights in the garden either) and was actually looking at planes, stars and for the ISS originally when I first noticed a group of bats flying over our garden which prompted me to observe them over a period of weeks.

I remember watching a documentary years ago about blindness. When going out, the blind person would use their fingers clicking to judge how far away objects were. They copied this from bats. Iirc, bats make 'clicking' noises so they know how far away objects are. I'm sorry I haven't explained that very well, it was a long time ago. But I'd say they are using this 'sound technology' to gauge where you window is, thus avoiding it. However, what they are doing that for is another matter! You don't have a nice cake on the window ledge do you?

Was it called something like 'Echo location?'

I have a maternity roost above my bedroom window. The little bats do a lot of flying round in circles and banging into the window! They also poo all over the window. Do this every year!

Yep same here! Also other bat colony members seem to fly around the entrance to the roost calling the young ones out.

I've heard of echo location but never actually looked it up. It does make perfect sense though! No cakes either, sadly.

Fascinating responses about baby bats and older bats encouraging youngsters out of the roost too. Makes me wonder if these bats had a roost in or around our house somewhere.

They're all bats.

That's a highly commendable observation.