Media & Education
BATS Magazine

Volume 35, Issue 1, 2016

Tracking British Bats

A decade-long bat-monitoring project in the U.K. builds on its success

Editor’s note: A longer version of this article by the late Dr. Kate Barlow (1970–2015) originally appeared in The Biologist (62(3) 2015). We share this excerpt in her honor. 

Volunteers CREDIT Anne Youngman Bat Conservation Trust 400px
Volunteers with the Bat Conservation Trust's Monitoring Programme.
Credit: Anne Youngman, Bat Conservation Trust.

Every year in the U.K., hundreds of dedicated bat lovers spend evenings sitting in their gardens watching gaps in their roofs, or wandering through British towns and countryside with bat detectors clutched in their hands. These amazing volunteers are taking part in the Bat Conservation Trust’s National Bat Monitoring Programme.

The initiative was established in 1996. Since then the Bat Conservation Trust ( has been working with its partners and volunteers to gather data on how U.K. bat populations are faring.
Why do we need to monitor bat populations? There are 17 species of bats that breed in the U.K., making up about a third of the U.K.’s mammal species. Many U.K. bat populations suffered considerable declines in the second half of the 20th century, but there is a lack of quantitative evidence from this period that allows us to determine the full extent of those declines. Then, during the 1980s and 1990s, there was a sharp increase in interest in bat conservation in Britain, at least in part promoted by new legislation providing legal protection for bats from the Wildlife and Countryside Act of 1981. In the 1990s, as part of work investigating habitat use by bats in the U.K., researchers demonstrated that volunteers could be coordinated successfully to carry out bat surveys at a national level. This work, and the increasing need to be able to report on the status of bat populations, led to the establishment of the National Bat Monitoring Programme, supported by government funding.

Brown long eared bat
Brown long-eared bat in the U.K. Credit: John Haddow, Bat
Conservation Trust.

The project relies on volunteers to take part in different surveys throughout the year, including summer counts of bats emerging from maternity roosts, winter counts of bats in underground sites such as caves and mines that bats use for hibernation, and summer bat detector surveys looking at activity levels of bats in different habitats.

Recently, the project published its results, analyzing data on 10 bat species or species groups collected by over 3,500 volunteers at more than 3,200 sites across the U.K. for a 16-year period (1997–2012).1 Our results show a generally favorable picture for the bat species that we monitor: All species are showing a stable or increasing trend over the period of the study from at least one survey type.

While these are positive results, such increases in bat populations are likely to be only a small start in their recovery. There is still much work to do—first, to unravel the main factors driving the changes, and, second, to expand our monitoring right across the range of bat species we have in the U.K., as some of the U.K.’s rarer species that are habitat specialists are not currently included in our monitoring program ecause they are difficult to monitor or rarely encountered.

The bat monitoring trends we produce not only help us to understand how bats are faring and help us shape our conservation work; our data contribute to European reporting requirements and provide one of the 26 U.K. biodiversity indicators used to assess the U.K.’s progress toward its biodiversity targets. We would not be in a position to provide those key facts on bats without the commitment and enthusiasm of all of our volunteers. People power really does make a difference.

UK Bats

To learn more about the Bat Conservation Trust’s National Bat Monitoring Programme, as well how to participate, visit

All articles in this issue:

Stay up to date with BCI

Sign up and receive timely bat updates

BCI relies on the support of our amazing members around the world.

Our mission is to conserve the world’s bats and their ecosystems to ensure a healthy planet.

Please join us or donate so our work can continue.