Honing our bat skills

Monday, February 14th, 2011

Most of our ecologists take active roles in a variety of voluntary surveys and monitoring projects for habitats and species. These are valuable learning opportunities, not only in survey techniques, ID skills and conservation work but also in helping to inform what works effectively in conservation and habitat management, and how they can be applied in mitigation schemes.Senior ecologist Sarah Yarwood-Lovett

Our senior ecologist Sarah Yarwood-Lovett, recently donned thermals, several jumpers and protective gear to spend a Saturday in cold, damp caves and disused railway tunnels helping to monitor hibernating bats with the Sussex Bat Group. Hibernation surveys are specialised and are specified separately on bat licences. They are carried out by experienced bat workers to minimise disturbing hibernating bats, as disturbance may cause bats to deplete their energy reserves resulting in an increase in the risk of mortality.

There are 18 species of bats in the UK, of which 17 are resident, breeding species. All bat species, and their roosts are legally protected but some, such as barbastelles, Bechstein’s and greater and lesser horseshoe bats, are specially protected as they are particularly rare. Bats use different types of places, including trees and buildings, for their summer, maternity and hibernation roosting sites.

Hibernation sites also include ice houses, hollow trees, mines and cellars. Hibernation sites should have cold, stable temperatures and dark, humid conditions to be suitable for bats. These conditions enable them to lower their metabolism and become torpid through the winter when their food supply of insects is low.Brown long-eared bat

Very little is known about hibernating bats, especially species such as pipistrelle, and so these surveys contribute considerably to our knowledge and understanding of these mysterious mammals. During this particular survey, our ecologist spotted hibernating Natterer’s bats, Daubenton’s bats, brown long-eared bats, and whiskered/Brandt’s bats (it’s not possible to differentiate between these last two species in hibernation surveys and close inspection is required!).

Survey findings are passed on to the Bat Conservation Trust who collate the monitoring information provided by similar groups across the UK. Many sites are monitored over long term periods (many years, even decades) and this enables bat researchers to establish population trends and see clearer pictures of what the different species of bats do at different times of the year.

In turn, these insights help inform the advice that we, as ecologists, can give to clients which aim to not only cover legal issues and ensure the welfare of these species but also to provide novel, inventive and successful site solutions.

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