Suffolk Bat Group produces new county atlas

Sue Hooton, of the Suffolk Bat Group,with a detecting device used to monitor bat species. Picture: G

Sue Hooton, of the Suffolk Bat Group,with a detecting device used to monitor bat species. Picture: GREGG BROWN - Credit: Archant

Suffolk’s bats’ secrets are being unlocked, thanks to new technology.

A brown long-eared bat - the species is common and widespread in Suffolk. Picture: HUGH CLARK/BAT CO

A brown long-eared bat - the species is common and widespread in Suffolk. Picture: HUGH CLARK/BAT CONSERVATION TRUST - Credit: Archant

Advances in technology are helping naturalists shed light on the lives of Suffolk’s bats - the often overlooked creatures of the night that have for so long been mysterious and misunderstood.

Hi-tech but simple to use and relatively inexpensive bat detecting devices and computer software have in recent years enabled identification of the sounds issued by unseen individuals to be made down to species level - and the Suffolk Bat Group has taken advantage of such new opportunities to increase our understanding of the lives and distributions of the county’s bat populations.

The group, formed in 1983 to record, research and conserve the county’s bats, has now published its new Suffolk Bat Atlas - a labour of love that builds on the group’s previous 2012 atlas and one that will greatly enhance conservation efforts on behalf of all the species covered in the publication.

Bats in Suffolk: Distribution Atlas 1983 - 2016 charts not only the areas in which each species is found in the county - it also charts the technological progress that has allowed group members to carry out their survey and achieve accurate identifications.

A barbastelle bat - the species is now being recorded more widely in Suffolk thanks to advanced det

A barbastelle bat - the species is now being recorded more widely in Suffolk thanks to advanced detection techniques. Picture: HUGH CLARK/BAT CONSERVATION TRUST - Credit: Archant


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In its introduction to the publication, the group says: “The main source of records for the first 15 years was from licenced members carrying out building surveys for English Nature (now Natural England). These early records are entirely random as they were all in response to requests from householders and developers asking for advice in various forms as a result of bats becoming fully protected under the 1981 Wildlife & Countryside

Act.

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“By the late 1990s, bat detectors were becoming more frequently used by both group members and other interested naturalists. However records from this method were not considered to be sufficiently accurate to species level for submission to the Suffolk Biological Records Centre (now Suffolk

Biodiversity Information Service).

Suffolk's single lesser horseshoe bat in hibernation. Picture: ARTHUR RIVETT

Suffolk's single lesser horseshoe bat in hibernation. Picture: ARTHUR RIVETT - Credit: Arthur Rivett

“By 2000, computer software had been developed by which the sounds on the detectors could be recorded digitally and then analysed using programmes such as Bat Sound and Batscan. The sounds are converted into spectrograms and the various species display varying images enabling a positive identification to be made for most bats.

“This transformed bat surveying and, although still not quite as instant as watching birds through binoculars for identification, an evening of recording can be quickly downloaded and the spectrograms viewed and compared with known images, enabling the species encountered to be positively recorded.”

Since the 2012 atlas, lower prices of static detectors had meant they were no longer only available to “consultants on expensive contracts”. The group now owned two units and the British Trust for Ornithology (BTO)-based Norfolk Bat Project had made units available on loan to a number of individuals in Suffolk. The units could be left at sites for several days and record all bat activity over the period, greatly increasing the number of records.

“All this means that bats can be identified without having them in the hand, which requires a licence, and so opens bat surveying to many more people,” the groups says.

Barbastelle bat

Barbastelle bat - Credit: Arthur Rivett

From 2000 the group had selected areas for organised bat surveys - the “main driver” had been to investigate the distribution of barbastelle bats. It was an “obvious species to concentrate on” as it is rare in a European context and, until the mid-1990s, East Anglia was thought to be its stronghold. It was “relatively easy” to identify from detector recordings and by choosing suitable habitat, and so the records of barbastelles and many other species had increased greatly, says the group.

The atlas maps had been split into pre and post-2012 for comparison, with most records being from detector surveys run by the Suffolk Bat Group, the Bat Conservation Trust, the BTO or consultants.

The group adds: “In Suffolk, we now have more licensed bat workers than at any time in the group’s history, but the number of visits requested by Natural England is much less than in former times.

“Bats’ protected status means they are routinely surveyed for planning developments, not just for houses and building conversions, but also for wind farms, power stations and other large infrastructure projects.”

Members of the Suffolk Bat Group check bat boxes in Thetford Forest. Picture: ARTHUR RIVETT

Members of the Suffolk Bat Group check bat boxes in Thetford Forest. Picture: ARTHUR RIVETT

In its section on barbastelle bats - one of Europe’s rarest species that is listed as endangered or vulnerable - the atlas says that between 2000 and 2012, Suffolk records increased from 15 locations to 64, and since 2012 a further 74 locations have been confirmed. It adds: “However, this does not mean they are more common, it is just that we are better at finding them.”

A total of 13 species are recorded in the atlas - the rarest of which is the single lesser horseshoe bat found hibernating in west Suffolk in 1996 - “probably the most exciting find in the history of the Suffolk Bat Group.”

It was found at the same site every winter until 2015 but had not been recorded since March 15, 2016. The atlas adds: “It is unknown whether it was a lost or displaced individual,or whether there is a small population existing somewhere in west Suffolk waiting to be discovered.”

More information about the group can be found at www.suffolkwildlifetrust.org/suffolkbatgroup A small number of printed versions of the atlas may be available from the group.

Naturalist Arthur Rivett, one of the driving forces behind the Suffolk Bat Group, with a bat detecto

Naturalist Arthur Rivett, one of the driving forces behind the Suffolk Bat Group, with a bat detector. Picture: ARCHANT

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