Tracking Rare Bats in the Bovey – Barbastelle Tracking Diary (part 3)

Radio Tracking Training – On Site and Fully Equipped

The barbastelle bat is one of the UK’s more rare bats and there is a lot we don’t know about its life, its behaviour and its habitat needs. The good news is that the barbastelle has been found in the Bovey valley and, under the Moor than meets the eye scheme, the landscape partnership has put together a plan to study this small flying mammal.

On Saturday 25th April the barbastelle bat tracking team met at the Yarner Woodland Centre for the third time to start their practical radio tracking training. Still keen to commit their time to the study, the 25 volunteers signed up and paired up into survey teams for the coming months’ work.

Back at the helm, Andy Carr (PhD researcher at the University of Bristol) outlined the training for the day. This would be the first time the volunteers would use the radio tracking equipment and, splitting into three groups, an experienced bat tracker was on hand to supervise each one. Andy continued to set the scene on the overall survey – how, earlier in the week a number of bats had been trapped to select one for tracking. A male barbastelle, now named Bert, was tagged and ready for action. Interestingly, another bat was trapped and suspected to be a recently discovered species of Alcathoe bat. It’s very similar to the barbastelle, so similar in fact, that only a DNA check on its droppings will confirm this new discovery, the first in Devon.

Time for the tracking training to begin for real. Fully equipped groups assembled outside to discuss plans to find a live tag hidden somewhere in the oak woods – a needle in a haystack! Setting the receiver to the right channel, aerial aloft, they were ready. The basic rule of radio tracking is to find a high vantage point, so all three groups set off on their three different routes to gain altitude. Light rain had arrived and, pushing through knee-high wet bilberry the volunteers climbed, stopped, checked and listened for a signal. Gradually a feint beeping led the group through the trees, pausing now and again to make sure they were on track. As the beep got louder, careful adjustment of the “gain” sensitivity on the receiver indicated their distance from the target. Not far from the tag the volunteers needed to look for likely roost sites; split bark or torn, decaying braches on oak trees are the preferred home of the barbastelle. Groups of volunteers who took different routes at the start began to converge. “It must be close now” they agreed. Walking in ever decreasing circles, only one or two trees had potential roost spots and finally, there it was. A pair of red eyes on a fabric bat nestled in the crack of a torn branch, but the transmitter tag was genuine though. A successful first stage of radio tracking training was rounded off with a chat about how radio tracking can be used to follow a moving bat and record its progress.

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Photos: radio tracking training, locating the transmitter in an oak tree

The Evening Shift

Resuming in the car park above the Bovey valley at 8pm the volunteers assembled with aerials and receivers to get their first “fix” on Bert’s roost location. The signal was weak and intermittent but benefited from a boost by the use of a Land Rover roof rack as an amplifier. Two way radios were shared out as groups of trackers set off to different vantage points around the valley. To have the best chance of picking up a signal a good promontory was found and volunteers waited, aerials raised and receivers hissing in anticipation. Rain came and went, clouds drifted around the valley and the sky darkened. The group down in the valley were the first to get a strong signal as they were reporting from outside Bert’s roost. Birdsong gradually drifted away but still no sign of bats flying. A half-moon was visible between clouds and described by 11 year old Gillian over the two way radio that “the other half was behind the darkness”! Moths began to appear in the deepening gloom, skipping between gorse flowers, but still no bats. One tawny owl in the bottom of the valley was the only bird heard – then a bat fluttered overhead, taking us by surprise. Not Bert, but a bat at least, picking off the moths. In real darkness it dawned on the volunteers and experts alike that Bert wasn’t coming out. He’d probably fed well the previous night and, in the cold, damp conditions, decided to stay under cover. The general opinion was to concur with Bert and head home.

The weather may have been wet but the volunteers’ enthusiasm was not dampened. They had all learned a lot over the training day and would be back to hone their skills another night. Some will also be back to trap and tag more bats as female members of Bert’s colony will need to be recruited. With a bit more practice the new bat trackers will be able to put together the results and provide a full picture of the movements and habits of the rare barbastelles resident in these woods in East Dartmoor National Nature Reserve.

The Bovey valley barbastelle tracking project is coordinated by the Woodland trust and Natural Engalnd as part of the Moor than Meets the Eye Landscape Partnership.

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Photos: Team Barbastelle, Andy Carr finding a signal in the Bovey valley

Article by Matt Parkin

Woodland Skills Weekend in the Bovey Valley- Charcoal, Hurdles and Heavy Horses

20150412 MP Woodland trust Bovey logging event (1)On an early spring morning at Pullabrook Woods the sights, sounds and smells of traditional woodland crafts filled the riverside meadow. After a winter of thinning work removed the shadier areas of dense woodland and let the light in, some residual timber stacks remained and April is a perfect month to demonstrate the woodland skills needed to convert this into valuable woodland produce. While softwood thinnings are taken away for timber and wood fuel, the hardwood thinnings can make good charcoal and traditional hazel hurdles.

Starting early on Saturday the charcoal making team got warmed up by stacking the cut lengths of timber, using two different styles of stacks from two different eras. The first was an earth clamp; a conical stack covered in soil and turf. The second used a steel kiln but both were built around a central core left open till the last minute when buckets of hot ash were dropped in to ignite the wood.

As the sun climbed, the morning heated up and the atmosphere warmed with more people arriving in the meadow to see the activities in progress. Interesting skill displays for all ages included a forest school, hazel hurdle making and a heavy horse hauling logs from the woods. They all used material cut from the valley to show the techniques developed over the centuries. Children round the campfire made artists’ charcoal in a biscuit tin and crafty people had a go at riving hazel rods and weaving a hurdle. But the star of the show had to be the heavy horse with studded iron shoes, making easy work of dragging full length Scots Pine logs from the forest floor. The partnership between man and his beast of burden left people in awe of the combination of power and control.

After a busy day a small group of charcoal burners sat beside the campfire, monitoring the stacks of smoke and steam into the night while watching satellites traversing the starry sky. A cold and clear April night in the woods was no challenge for the river Bovey otter heard making his way up stream but for the few who stayed in the woods all night the frost on the tents meant a chilly start to Sunday. A bacon and egg roll provided the breakfast boost for the workforce to continue monitoring the charcoal burn; waiting for the smoke to change from white to distinctive blue. A spring morning was captured by the damp and still air which trapped the smoke at tree top level until it was released by the sun’s warm thermals.

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Later, people returned to the meadow as the ground warmed and the birds and beasts emerged. This meadow is a refuge for various species of insects including the rare violet oil beetle. With all the activities in full swing once again the warm ambience complemented the bright spring day.

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After more horses, hurdles and charcoal the visitors left the valley with happy memories of woodland skills and the aromatic wood smoke in the air. Only the charcoal burners remained to shut down the smoke stacks to cool in time for their return in two days to collect the fruits of their labours; sack loads of good quality clean-burning fuel. Spring time in the meadow will now be left for the Bovey valley otters, wildflowers and butterflies to provide the next show. It looks like it could be a barbecue summer.

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by Matt Parkins