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Whiskered / Brandt's bat trends for Great Britain

Myotis mystacinus / brandtii

Species factsheet Whiskered bat / Brandt's batDistribution and abundance

A combined population trend is produced for these species due to the difficulty of separating them with confidence in the field. The GB-level population trend for whiskered/Brandt's bat from the Hibernation Survey are shown on this page.

Population trends are also produced at a country-level for whiskered/Brandt's bat in England and Wales. These species are only rarely recorded in Scotland, therefore insufficient data are available to calculate a trend for this country.

 


Hibernation Survey

GB index of whiskered/Brandt's bat population from Hibernation Surveys

Whiskered/Brandt's bat hibernation survey trend GB

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 38.5% above the 1999 base year value, equivalent to an annual increase of 1.9%. Several years of high average counts since 2008 have pulled the index slightly upwards, however overall there has been no significant change in the smoothed index since the baseline year. There are no significant differences between trends for England and Wales.

From all years for which data are available (1990-2016), counts from 231 sites contribute to the trend (sites surveyed in two or more years with whiskered/Brandt's bat recorded in at least one year).

 


Summary of survey results

The trend from the Hibernation Survey shows no significant change in the smoothed index since the baseline year. Populations of whiskered and Brandt's bat combined are considered to have been stable in Great Britain over the period 1999-2016. However this trend should be interpreted with caution as it combines data from two species with differing ecological requirements and potentially differing conservation status. This uncertainty has been compounded by the discovery of Alcathoe bat in the UK in 2010, a third cryptic species in this species group. The distribution of Alcathoe bat in the UK is poorly known although it is thought to be localised and rare. It is likely to have occurred in the UK prior to it's discovery in 2010, so it is possible that counts of whiskered/Brandt's bat made during the Hibernation Survey may also include Alcathoe bat. Further work is required to facilitate the reliable identification of these species and their differing ecological needs.

 


Distribution and abundance

The two species are uncommon but widespread in England and Wales. Whiskered bat is rare in Scotland and Northern Ireland. It is also recorded in the Channel Islands. There are only a few records of Brandt's bat in Scotland and this species is absent from Northern Ireland.

Population estimate 

The population estimates are considered to be poor and should be treated with caution. Estimates are based on very limited or no population data and rely on expert opinion only.

Country

UK

England

Wales

Scotland

N.Ireland

 Whiskered bat numbers

64,000 

30,500 

8,000

1,500 

24,000 

Brandt's bat numbers

30,000

22,500

7,000

500

does not occur

 Source

 

 Harris et al. 1995

 Harris et al. 1995

 Harris et al. 1995

 Russ 1999

  


References

Harris S., Morris, P., Wray, S. & Yalden, D. (1995) A review of British mammals: population estimates and conservation status of British mammals other than cetaceans. JNCC, Peterborough.

Russ, J.M. 1999. The Microchiroptera of Northern Ireland: community composition, habitat associations and ultrasound. Unpublished PhD thesis. Queen’s University, Belfast.


Return to:

Top of pageSpecies population trendsReport HomeContents page

 

Whiskered bat factsheet

 

Listen to how a whiskered bat sounds on a bat detector

 

Brandt's bat factsheet

 

Listen to how a Brandt's bat sounds on a bat detector

 

 

Current distribution of whiskered bat in the UK

(Map taken from 3rd Report under Article 17 on implementation of the Habitats Directive in the UK, JNCC 2013)

Whiskered bat distribution

 

Current distribution of Brandt's bat in the UK

(Map taken from 3rd Report under Article 17 on implementation of the Habitats Directive in the UK, JNCC 2013)

Brandt's bat distribution

 

 

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