Batman Returns! Hunt for night-time creatures resumes as Norfolk Bat Survey is relaunched

Brown long-eared bat. Photo: Norfolk Bat Group Brown long-eared bat. Photo: Norfolk Bat Group

Monday, April 21, 2014
9:25 AM

It is a case of Batman returns.

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The bats of Norfolk

Experts have said there are bats everywhere in Norfolk, from Norwich city centre to the Broads.

The peak time for people wanting to see bats or record their sounds is at dusk, when bats leave the roost hungry to feed on flies.

There can be another peak in the early hours when the bats return, but on a cold night they will not stay out for that long.

More than a dozen types of bat live in Norfolk, but the overwhelming majority are either common pipistrelles, pictured above, or soprano pipistrelle – which accounted for at least 91% of all bat recordings in last year’s survey.

Sound files of echolocation calls are analysed by special computer programs, which produce a list of the bats recorded from the site – which is shared with the volunteer who recorded them.

Last year there were more people wanting to take part than there was bat-detecting kit in some parts of the county.

Norfolk’s first countywide bat survey was conducted last year, and now it is back bigger than ever.

An army of volunteer Batmen and women scoured around 8% of the county for bats in 2013, and ecologists hope to up this to 20% this year.

People are invited to borrow bat-detecting kit from one of 21 collection points across Norfolk, and post their sound recordings to the bat HQ in Thetford for analysis.

More than 250,000 high-quality recording of bats from around 450sq/km of Norfolk were received last year.

Bat monitoring centres across NorfolkBat monitoring centres across Norfolk

Bosses cross off each square kilometre of the county once it has been analysed, and hope to cover as much as possible to build a clear research picture.

Feedback is posted back to bat volunteers as soon as their data has been studied by experts.

Dr Stuart Newson, who is project manager for Norwich Bat Group and senior research ecologist for the British Trust for Ornithology (BTO), said the initiative is unique.

“Norfolk is the only county that’s trying to do anything like this, so it’s pretty novel,” he explained. “Last year it was a bit of an experiment.

A soprano pipistrelle bat rescued. Picture: Denise BradleyA soprano pipistrelle bat rescued. Picture: Denise Bradley

“We covered about 450km/sq and people are so interested – you get schools and Scout groups joining in.”

While the project remains “low budget”, Dr Newson said more than 350 people got involved last year and it was a word of mouth success.

This year organisers have bought more recording equipment and are devoting more time to publicising their work, to get even more people involved.

The number of so-called bat monitoring centres has increased from 19 last year to 21 – with the addition of sites at Aylsham and Pulham St Mary.

And there has been plenty of interest.

“I think the main appeal is people are surprised at what they have in their back yard,” explained Dr Newson.

“People who have borrowed a detector might have seen a bat three years ago from their garden.

“Then they put up a detector and get 2,000 recordings of five different types of bat in a night.

“People don’t realise, as they’re nocturnal, that there are bats everywhere.”

The bat-detecting kit is a green box on the ground, with a pole into the air with an ultrasonic microphone on it.

People must put the device out before dark, it switches itself on and registers the echolocation calls of passing bats overnight.

The survey requires three different points, ideally at least 200m apart, to be surveyed on consecutive nights within a 1km/sq.

A memory card of the data is then posted to the BTO office in Thetford, together with the grid reference where the sounds were recorded.

“There’s two things we’re really trying to do,” said Dr Newson. “I would like to encourage people who took part last year to do the same square kilometres again as then we can look at change in population over time.

“We don’t know if they’re increasing or declining as we don’t have the data.

“We would also like to improve coverage, getting an idea of what’s present.

“I know it’s more difficult to get people in the west of the country as there’s just fewer people.”

The project is a partnership with local bat groups, local and national organisations and local libraries, to improve people’s understanding of bats in the county.

To register your interest to get involved, see www.batsurvey.org/sign-up

After selecting a 1km/sq on the website map you will be given a web link to a site where you can reserve a detector to use from the most

convenient bat monitoring centre to you.

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