Bat detectives at Gibside
The old buildings, meadows, ponds and trees at Gibside make a fantastic habitat for seven different species of bat. In 2008, thanks to tiny radio tags, we started a project to discover more about the secret life of these bats, like exactly where they were roosting and feeding.
For many years we have carried out evening bat surveys on Gibside's old buildings and mine entrances to see if we can identify where our bats are roosting (or resting). Bats and their roosts are protected by law, so if we can find their roosts we're in a better position to look after them. But bats can roost in trees as well as buildings, and with the amount of woodland we have at Gibside, it was difficult to know where to start looking! That's when the idea for the bat radio-tracking project was formed.
Tracking down the bats
We caught, radio-tagged and tracked bats to see exactly where they were roosting and where they travelled to feed. We applied to Natural England for a license to be able to do this and fully trained bat experts helped us out.
Bats were caught using a trap specially designed to catch bats without harming them. Each bat was then weighed and measured, and the species was identified. If the bat was heavy enough, we attached a radio tag the size of a grain of rice with glue in between their shoulders. The glue would dissolve after around 10 days, and the tag would then fall off.
Once the bats were tagged, our team of volunteers tracked them down to their day-time roosts, and at night we tracked the bats feeding and flying at Gibside. Altogether we tagged 17 bats, and these bats led us to 21 new roosts. We tracked one of the bats to a house in the local village, and then counted 335 more bats emerging from the house that evening! This was a great result because now we know about these roosts, they can be protected for the future.
Roost sweet roost
During the bat project, all of the woodlands at Gibside were assessed for their suitability for bats. Plantations of conifer trees, for instance, provide fewer of the cracks, holes and loose bark that bats need to roost in. Areas of broad-leaf woodland are more valuable in this way. Where woodlands were found to be less suitable for bats, we have put up special bat boxes to provide more roosting places.
Building a bat roost
Another part of the bat project was to create a roosting space for brown long-eared bats at the Gibside Stables Learning and Discovery Centre. This involved fixing special slates and tunnels through the roof, so the bats can get inside the loft.
Brown long-eared bats have been seen at the centre and near-by farm buildings before, so we hope they will discover the new loft space and move in soon. We installed a CCTV camera in the loft, so when the bats do move in, visitors to the centre will be able to watch them roosting.
This project was made possible thanks to £25,000 of funding from County Durham Environment Trust, the Friends of Gibside and the Cleveland Association of the National Trust.