Thursday, 10 September 2015

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.