Today was graduation day in the BrumBats flight cage, where we moved 8 common and 3 soprano pipistrelle bats into the flight (which is basically an aviary in which we teach orphaned bats to fly). There are another 15 bats waiting to move in, but they need to be self-feeding on mealworms before that’s possible. I took a few photos of our new residents, and thought I’d take a minute to show you the difference between our two most abundant pipistrelle species (there is a third, Nathusius’s Pipistrelle, which is larger and rarer – and I’ve never even seen one!)
The following photos are all common pipistrelles – they have a dark face (aka the bandit pipistrelle) and quite perky ears.
Now, if you compare the common pipistrelle (below, left) to the soprano pipistrelle (below right), you can see that the soprano is pinker in the face, paler in general, and has a slightly more ‘puggish’ nose.
There are also a few other differences, like a tiny bump between the nostrils of sopranos (called an internarial ridge) and an extra vein in the wings of common pipistrelles (although sopranos often have this so it is not diagnostic on its own). In general, the two pipistrelle species are separated by a combination of these features, coupled with the use of a bat detector, as sopranos echolocate at a higher pitch (55kHz) compared to common pips (45kHz), thus living up to their name.
Some people claim to be able to smell the difference, as many people (sadly, I am not one of them) claim that soprano pips have a distinctive musty odour. (I CAN, however, smell asparagus wee*, and apparently not everyone can, so I conclude that my nose is functioning adequately.)
*If you don’t know what I’m on about, you need to google it.