Need help with a bat?

Follow our advice

or call us on 0345 1300 228

Common pipistrelle trends for England

England-level population trends for common pipistrelle from the Field Survey and the Roost Count are shown on this page.

Population trends are also produced for common pipistrelle for Great Britain and Scotland. 


Field Survey

England index of common pipistrelle population from Field Surveys

Common pipistrelle bat field trend EnglandNote: The graph above shows the unsmoothed index value for each year (green crosses), the smoothed trend (solid line) and 95% confidence intervals (dotted lines). The smoothed trend for 2016 is shown as a dashed line to indicate that it is provisional.

The smoothed index is currently 96.6% above the 1999 base year value, equivalent to an annual increase of 4.1%. The smoothed index increased steadily between 1999-2006, was relatively stable between 2006-2012, and since 2012 is has been increasing again. Overall there has been a significant increase in the smoothed index since 1999. There are no significant differences between trends for each region within England.

Data from 515 sites contribute to the trend analysis in England.


Roost Count 

England index of common pipistrelle population from Roost Counts

Common pipistrelle bat roost trend England

Note: The graph above shows the unsmoothed index value for each year (green crosses), the smoothed trend (solid line) and 95% confidence intervals (dotted lines). The smoothed trend for 2016 is shown as a dashed line to indicate that it is provisional.

The smoothed index is currently 54.3% below the 1999 base year value, equivalent to an annual decrease of 4.5%. There has been a significant decline in the smoothed index since 1999. However it is likely that this species' frequent roost switching results in a negative bias in the Roost Count trend (see Robustness of Monitoring) and this trend is not therefore considered a reliable measure of population change for this species. We are currently investigating the causes of this negative bias in more detail and exploring ways to correct it (see Developments and Future Directions). There are no significant differences between trends for regions within England.

Data from 388 sites contribute to the trend analysis in England (sites surveyed in two or more years).

 


Return to Common pipistrelle population trends; Report home page; Contents page

You should follow us
Bookmark and Share
 
E-bulletin

Subscribe today to receive the latest on bats and BCT direct to your inbox.

Bat Helpline

0345 1300 228