20th January 2014

Tiny Bat Crosses the North Sea!

Tiny bat, ringed in the UK, found in Netherlands, 600 kilometres (as the bat flies), from where it was ringed; providing the first record of a bat crossing the sea from the UK to mainland Europe!

Bat experts in the Netherlands and the UK are working together to learn more about this remarkable journey and its implications for bat conservation and offshore windfarms.

We believe the tiny bat, a Nathusius' pipistrelle, which typically weighs around 6-15g and is about the size of a human thumb, flew from Blagdon, near Bristol, in the South West of the UK across the country and on over The North Sea before settling in a farm building in the Netherlands about ½ km from the coast: a direct journey of 596 kilometres (370 miles).

The bat was found on 23rd December 2013 by Teddy Dolstra, from the Friesland Mammal Working Group who regularly monitors bats roosting at the site.

The exact location of where the bat was found is Hoarnesstreek 2,Pietersbierum, Franekeradeel, Holland.

Sadly, the animal had already died, but because it was carrying a miniature identity ring, he was able to discover that the remarkable creature had been found previously in the UK

This could be the proof that these little bats do successfully migrate across The North Sea

The movements of Nathusius' pipistrelles both around the UK and between the UK and the continent, are currently a mystery. They are elusive creatures, and are too small to carry devices such as satellite trackers used to monitor bird migration. In some areas, like Blagdon, several male bats have been found, but females are either absent or scarce and are believed to visit only on their migration route elsewhere.

On the continent some migration routes are well known and it is established these tiny bats can travel very long distances over land. There are several records of them bats landing on oil platforms or boats in the North Sea but this is an exciting find, showing that the bat not only made its way from one side of England to the other, but then crossed the sea.

Daniel Hargreaves, who ringed the bat back in 2010, says of the discovery: "We have hypothesised for a long time about the migration of bats to and from the UK but it's very difficult to prove. This finding was a great surprise and is helping us to understand the huge journeys these bats can make. We have only ringed 34 bats at Blagdon lake so to receive a record like this is astonishing; it's incredible to think that this little bat has flown a distance of at least 600km, avoiding hazards like roads and wind turbines, and for it to safely cross the sea is remarkable."

Lisa Worledge, Bat Conservation Trust: "The timings of peaks in Nathusius' pipistrelle recordings in spring and autumn, as well as records from North Sea oil platforms, have long suggested that some of these bats migrate. This discovery provides the first direct evidence that a British bat migrates over the sea between the UK and continental Europe

Dr Fiona Mathews, University of Exeter: "Nathusius' pipistrelle is one of the species most at risk from land-based wind turbines throughout Europe. We now urgently need to identify the migration routes they use to cross the sea between the UK and continental Europe: offshore wind farms in the wrong place could be very bad news. In the autumn, we installed bat detectors on board Britany Ferries crossing to and from South-West England. We are analysing the data to find out when and where bats are recorded at sea and clearly now need to extend these surveys to include The North Sea."

INVITE: If you are interested in meeting Daniel Hargreaves and Teddy Dolstra from the Friesland Mammal Working Group who found the bat in The Netherlands, they will both be visiting the site of the lake in Blagdon where the bat was ringed, on 17 January 2014.

Notes for editors:

This bat, a male Nathusius' pipistrelle was ringed A4030 on the 14.10.12 in Pipe Bay at Blagdon lake. It weighed 7.6g and forearm 34.6. It was found 596 kilometres from where it was ringed!

Have a look at our Nathusius' pipistrelle information sheet.

More information on Nathusius' pipistrelle can be found at http://www.nathusius.org.uk/

Dr. Fiona Mathews at the University of Exeter leads the National Bats and Wind Turbines Project. She will analyse samples from the bat in an attempt to establish whether it originated in the UK or the Netherlands, and whether it had only recently arrived in the Netherlands or had spent the summer there. F.mathews@Exeter.ac.uk

The Bat Conservation Trust (BCT) is the only national organisation solely devoted to the conservation of bats and their habitats in the UK. Its network of 100 local bat groups and more than 1,000 bat workers survey roosts and hibernation sites, and work with householders, builders, farmers and foresters to protect bats. www.bats.org.uk

Images of Daniel Hargreaves and Nathusius' pipistrelle, can be provided high res, free to use with appropriate copyright accreditation.

For further information and images and to arrange interviews please contact : Joe Nunez, Director of Communications and Fundraising. E-mail: jnunez-mino@bats.org.uk Office: 0207 8207168