Gatwick's Dark Knights

After only making it back home in the wee hours of this morning, I was awoken at 7.30am to some great news; council workers had decided to try to repairing the communal recycling bin outside my bedroom window with a sledgehammer. I guess I'll really appreciate this the next time I take out the recycling.

Location: edge of Brockley Wood, adjacent to the north west aircraft stands. 

Ah well, the late finish was totally worth it as we got to see a whole selection of bats utilising the site on the River Mole side of Brockley Wood. I also finally got to see a fairly common bat species which has eluded me for 5 years!

Martyn measuring the forearm length of a bat while Laurie takes notes

Martyn Cooke (Surrey Bat Group) is a licensed bat surveyor, who has been monitoring the bats around Gatwick for several years. A harp trap is his preferred tool, one of safest ways to capture bats and minimise their stress, in order to collect scientific data and feed back to the Bat Conservation Trust.

Harp trap set up on River Mole floodplain

The northern edge of the woodland is sheltered by a massive environmental bund, blocking out light and sound from the airfield. The weather conditions were almost perfect, with low cloud, barely a breeze and a balmy 17 degrees celsius. This turned out to be the best night's trapping I've attended in terms of species diversity; we caught 5 species in the harp traps and at least 2 others on the detectors. 

An electronic lure plays out species-specific bat calls

Here's our haul of bats, in order of appearance...

Soprano Pipistrelle (Pipistrellus pygmaeus)

Soprano Pipistrelle wing

Whiskered Bat (Myotis mystacinus)

I was super excited when I released this one; just look at his little mouth!

Brown Long-eared (Plecotus auritus). He does have some eyes there, he's just blinking

The new one for my list is was the Daubenton's Bat! That brings my number of wild UK bat species seen up to 9.

Daubenton's (Myotis daubentonii)

These funny looking dudes have big bald patches around their eyes, and are specialists at hunting over water, scooping up small insects while in flight with their big tail membranes.

I didn't manage to get a good shot of the membrane, but we can confirm that this one is a fella

Lovely dark face of a Common Pipistrelle

Common Pipistrelle (Pipistrellus pipistrellus) female

Although we didn't trap one of the rare Bechstein's tonight (previous post about our first Bechstein's at Gatwick) or Martyn's target species the Nathusius' Pipistrelle, we did pick up this Myotis bat call on Martyn's sonobat, which he thinks could be one of the little dudes with attitude...

Bechstein's call?

Thanks to Martyn, Fiona, Laurie, Rina, Luke and Ryan for giving up your valuable time. Also to the bats for doing your bit for science; you all rock.

North West Zone. Approximate harp trap locations in yellow, mist nets in blue

Dark Knights at Gatwick

Bat activity transect C, Land East of the Railway Line, July 11th 2015

It has felt like a good year for bats around our biodiversity sites, with lots of exciting acitvity monitoring by Laurie Jackson, Martyn Cooke and volunteers from Surrey Bat Group. We've been using 3 different survey methods here: activity surveys (walking set routes called 'transects', with bat detectors and recording equipment); trapping surveys (with Martyn's harp traps, loud speaker and bat call software system); and box checks (annual checking and cleaning of our woodland bat boxes).

Powerline Ride at dusk, Horleyland Wood

Although rarely seen, bats actually make up around a third of UK mammal species and so are a significant players in our ecosystems. Also being insectivores, they are directly affected by any crashes in invertebrate populations and are great indicators of our countryside's overall health.

Bat box recorder and logger 

Bat logger live sonogram image

This recording equipment is all a bit beyond me, but Martyn Cooke (who also works in air traffic control at Gatwick) loves his tech and is a dab-hand at collating and translating this data.

Measuring the forewing of a Common Pipistrelle.

(To handle bats, you must be trained and hold appropriate licenses.)

Weighing a Pip in a cup

The biometric data collected includes the species type (some can only be identified by close examination in the hand), weight, sex, rough age, breeding condition and general health of the individual. I need to check again with Martyn, but I think we are up to 10 different species of bat recorded at Gatwick.

Assessing wing joints and bone ossification to gauge the age.

This health check might look pretty intrusive for a bat, but they are only kept for a few minutes before they are released back out into the night.

Common Pipistrelle (Pipistrellus pipistrellus)

Brown Long-eared (Plecotus auritus)

Bats face many threats due to extensive habitat loss and fragmentation from development, as such they are all protected by UK and European law. You might associate bats with roosting happily in buildings, but they really need natural features such as grasslands, hedgerows and woodlands to hunt and forage in. The monitoring and conservation efforts led by organisations such as Bat Conservation Trust are of vital importance to conserve the UK's bat species. 

Get out of here, you.

Its not always deemed socially acceptable to be out in the woodlands after dark. but this bat work gives us special licence. Its also great to see and hear all the other wildlife out and about our biodiversity areas on warm summer evenings:

Light Emerald Moth (Campaea margaritaria)

Glow Worm (Lampyris noctiluca), female

Photo with flash reveals that a Glow Worm is a large beetle

We often hear the strange hoarse squeaks of juvenile Tawny Owls, which sound like their voices are breaking...

Plus a rather impressive (and one of my favourite) species we have resident in our woodlands...

Araneus angulatus male, a rare spider in the UK, restricted to the southern counties

To learn about monitoring bats in your area, why not check out your local bat group.