Daubenton’s bat

Myotis daubentonii

Key facts

Wingspan: 24 – 27.5cm | Head & body length: 4.5 – 5.5cm | Weight: 7 – 12g
When to see: April – October
Status: European protected species. Protected under the Conservation (Natural Habitats, &c.) Regulations 1994 (as amended).
Species on the Edge areas: Solway; Argyll and Inner Hebrides

Species information

How to identify

The Daubenton’s bat is a medium sized bat with a wingspan of 24 – 27.5cm. They weigh around 7 – 12g with red brown fur, pale underneath. They are often called the ‘Water Bat’ as they fly low over water bodies, catching insects, and often scoop their prey from the surface with their tail membrane or feet.

Daubenton’s bat calls range from 35 to 85kHz and are loudest at 45 to 50kHz. On a bat detector the calls are heard as a machine gun like series of regular clicks for bursts of 5 to 10 seconds.

Lifecycle

Mating takes place in the autumn and active males will continue to seek out and mate with females throughout the winter. Maternity roosts are occupied from late spring and sometimes until October. Young bats are suckled for several weeks and are fully weaned and able to forage for themselves at 6 to 8 weeks. Males or non-breeding females may aggregate during the summer to form their own communal roosts, but sometimes join maternity colonies. The average colony size is between 20 to 50 bats (up to 200). Daubenton’s bats hibernate underground over winter, in caves, tunnels and mines. Daubenton’s bats can live for up to 22 years in the wild, but an average lifespan of 4 to 5 years is probably more common.

Distribution

Daubenton’s bat is fairly widespread up to northern Scotland, in Ireland and on the Isle of Man.

Daubenton’s bat UK distribution map. Credit: Fourth Report of Daubenton’s bat (Myotis daubentonii) by the United Kingdom under Article 17, JNCC (2019)

Habitat and feeding

Daubenton’s bat is closely associated with fresh water lakes, lochs and slow moving rivers. They will roost in bridges, tunnels, buildings or trees. Daubenton’s bats hibernate underground over winter, in caves, tunnels and mines.

The Daubenton’s bat forages for small flies, such as midges, caddisflies and mayflies, just above water; it can even use its feet and tail to scoop up insects from the water’s surface as it forages.

When to see

All UK bats hibernate from around November to March. Daubenton’s bats can be seen during the summer months, about 40 minutes after sunset.

Protection

All bat species found in Scotland are classed as European protected species. They receive full protection under the Conservation (Natural Habitats, &c.) Regulations 1994 (as amended).

Threats

Despite severe loss of and damage to wetlands and waterways, Daubenton’s bat seems to be increasing in parts of its range. This may in part be associated with the increasing number of artificial water bodies, including gravel pits, reservoirs and flooded quarries. Also a low level of pollution may encourage a more consistent supply of certain insects.

However, the loss of diversity of aquatic insects has a detrimental effect on other animals and without very careful pollution controls, this would also affect Daubenton’s bats. The removal of waterside trees and disturbance to hibernation sites could also lead to a decline in this species.

What Species on the Edge is doing

We know that bat species are in decline in Britain in general, however we are lacking data on how they are doing specifically on Scotland’s coasts and islands. Species on the Edge teams in Argyll and Inner Hebrides and on the Solway Coast are working to learn more about how the Daubenton’s bat is faring in these areas and to support its continued presence there. Activity in these areas include:

Monitoring and surveying
Engaging with local communities to increase awareness of their local bats
Working with land owners to co-create habitat management plans

Our work for bats

A group of people in high-vis vests look towards a sunrise — Using our ears to survey bats on the Solway Coast

Solway Project Officer, Liam, tells us about surveying bats based on interpreting the ultrasonic echolocation calls of different species of bat.

A group of people stand on a road at sunset looking for bats — Species on the Edge Youth Panellist sets up the Outer Hebrides Bat Group

Species on the Edge Youth Panellist, Angus Maclean, tells us about the Outer Hebrides Bat Group he founded, his aims for the group and how they are getting on.

A group of four people stand outside and smile for the camera. — Sleat locals champion Skye’s bats

Bat Conservation Trust Officer, Cathryn, tells us about the fantastic work Sleat Community Trust are doing for their local bats.

Resources

If you are interested in learning more about bats, or are interested in supporting bats on your land, get in touch with your local Species on the Edge team.