Bat hibernation survey – Pooles Cavern

It’s hibernation season, the time when some bat workers get to go and share, hone or acquire the skills required to spot and ID a bat in a hibernation roost, and collect valuable data for the local bat group records. As you’ll know if you read my recent blog on my experience with South Lancashire Bat Group, it’s far from straight forward and more like something you work on over years than simply learn to do.

That survey had a mix of Whiskered Brandt’s and Daubenton’s. Very useful as they look so similar. I came away from it with a rare air of something like confidence in bat ID.

So I was excited to find out that I was to get the chance to go out on a mini hibernation survey with one of our licensed bat workers here on my work placement. Helen surveys the site at near by Pools Cavern and arranged to take me and a couple of others there one lunch time recently.

I hadn’t heard of Pooles Cavern. It sounds big at first but I knew the visit was to be a relatively short one in comparison to the day spent scrabbling around in the Lancashire mudstone caves so my mind painted a picture of a short, over-hanging rock face next to a road.

My lazy brain always places things right on the edge of a road. On an excursion with some work friends to try and see red deer rutting my subconscious uttered a familiar “Oh right!” as it discovered we were going to have to walk to see the deer and that they would not in fact be rutting in a field next to a car park.

Turns out Pool’s Cavern is a full on show cave. The Wooky Hole of Derbyshire. This happens occasionally with my not being from here, I haven’t heard of any of the famous local places so someone will say “do you fancy coming along on this job to Chatsworth” and I’ll say yes expecting another farm or brown-field site and suddenly there’s a giant country house in front of me with grounds and nobility and everything!

We surveyed a section of the caves. Helen, Tom, Becky, Andy and me. It was good fun, there weren’t many other people there and the caves are a magnificent site, especially when you weren’t expecting it.

We found 7 bats. I say we, none for me. Most were spotted by Tom who clearly has a good eye for it. I can’t decided whether I’m just not good at spotting them in their hibernacula or whether I’d find more if I asserted myself more in getting to have first look at more of the area we’re surveying. I do tend to linger at the back of the line a bit. I’m also seriously considering getting my eyes tested as when others do find them there are times when they’re a little too far away for me to make out the ID features.

But enough excuses…

The group found 7 bats. They were all Natterer’s apart from one brown long-eared and one Daubenton’s.

Here is the best picture of the day. Taken by Andy on his phone. Further proof of how awesome camera phones are these days. This is of the Daubenton’s hanging conveniently in arms reach for this beautiful shot…

Natterers Bat Andy Keen

Now as great as it was seeing this and the Natterer’s (my first experience seeing Natterer’s in the flesh) it took the confidence I’d gained in separating Daubenton’s and Whiskered Brandt’s and turned it on its head. Adding this 3rd Myotis species to the mix upped the game of ID from medium to hard. Like the other two is has pale belly fur and like the Daubenton’s the pinkness of its face is an ID feature. It’s also a similar size to the Daubenton’s. Here are the ID features (courtesy of Steve from South Lancs group following an email conversation about the bat in the photo):

Thick fleshy ears
Ears too short for Natterer’s
Ears curled back – behaviour of a disturbed bat, and a trait of Daub’s (we saw it a lot with captive/rehab Daub’s)
Ears dark in colour, Natterer’s are always pinky
Fur – medium shagginess, Natterer’s would be smoother
Greyish dorsal fur, indicative of juvenile – Natterer’s are more pale brown. (on W/B its very shaggy, and usually dark the base and golden or lighter tips- often visible as the fur is shaggy.)
On the pic there is a small bit of ventral fur above the wing, but not enough. Natterer’s bats have white ventral fur just above the forearm, between the pro-potagium and wrist
No white crescent of fur behind the ears
No reddish forearm (although it is in shadow, I can see its brown, but not dark enough for W/B)
As I write this I notice that the three/four species in question are lined up on the BCT poster by my desk. A reminder that bat ID isn’t supposed to be easy…

upload

…but that’s part of the fun.

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