Blenheim Estate: Woodland Bat Research 2018 – 2020

Senior Ecologist Helen Simmons undertaking a thermal imaging survey of Blenheim lake and the Grand Bridge.
Rare Barbastelle bat mist-netted on site.
Ecologist Mark Norris inspecting a crevice in the wall of the Grand Bridge.

Background

We have provided ecological support to the restoration of Blenheim Estate World Heritage Site for a number of years. This has included advice on the restoration of Blenheim Lake Site of Special Scientific Interest (SSSI), on renovation work to the Palace and estate buildings, and with regard to the restoration of the iconic Grand Bridge.

For work on the bridge we applied thermal imaging technology to identify bat roosts within the structure and inform mitigation. During the course of the work, which also involved automated survey, we recorded a number of notable bat species, including barbastelle and lesser horseshoe bat. The restoration works and our findings generated media interest, leading to an article in the Oxford Mail concerning bats at Blenheim, a feature on Countryfile and a visit by the town council.

Bat Research

Due to our interest in understanding more about bat use of the estate, along with the interest shown by the estate and local people in the bat community, we commenced a research project at Blenheim in 2018.

This project aims to gather data on the woodland bat assemblage of the site over a two year period. It will establish whether nationally and / or locally rare bat species use the woodlands, and is likely to result in the location of roosts of species of particular conservation concern. The work is being led by Senior Ecologist Helen Simmons, who is working in close collaboration with the Oxford Bat Group to deliver the field survey, the scope of which includes conventional bat surveys using hand-held detectors, mist netting and harp trapping. This is being complemented by the erection of bat boxes (which are regularly checked).

During the second year of the project the intention is that there will be further mist netting, with some post-lactating female bats radio-tracked to determine roost locations. Emergence and re-entry surveys of these roosts will then be completed, in order to understand numbers of bats using them and their likely importance.

All work will be completed under licence.

Outcomes

The work will be used to inform management of woodland and trees within the estate, in order to both avoid contravention of legislation when undertaking estate work and effectively conserve the bat population. We would also anticipate presenting the results at conferences and to local interest groups.

A summary of the research outcomes will be published on our website. All bat data will also be held by the Oxford Bat Group and made available to the local biological records centre.

Images

Left image: Senior Ecologist Helen Simmons undertaking a thermal imaging survey of Blenheim lake and the Grand Bridge.

Centre image: Rare Barbastelle bat mist-netted on site.

Right image: Ecologist Mark Norris inspecting a crevice in the wall of the Grand Bridge.