Natterer’s Bat Myotis nattereri [Kuhl, 1817]

Showing facial characteristics, Butcombe Bank © Nigel Milbourne, 2013

(Local, resident)

Status: Natterer’s are widespread in the UK, to a little north of the Great Glen in Scotland. The dam end of the lake is used for foraging, especially in and around patches of woodland e.g. along Butcombe Bank. However, they echolocate very quietly and are not picked up by detector surveys perhaps as frequently as their population suggestions they should. It is a largely sedentary species, with movements usually only between summer, swarming and winter roosts. Apparently, there are few known summer roosts of this species in the UK, though we have found as many as twenty individuals roosting together in boxes at the Pumping Station for several years.

Natterer’s group in box, Pumping Station © Nigel Milbourne, 2012

General Inofrmation: They are medium-sized bats that emerge about an hour after sunset when they mainly glean insects and arthropods from vegetation using the stiff bristles fringing their tail membrane. They feed in woodland among the trees where their broad wings and tail give them great manoeuverability as they hunt at a height of less than 5 metres, flying slowly and hovering close to the ground as well as, occasionally, venturing higher up into the canopy. The diet consists of midges, small moths, caddis flies, lacewings, beetles, small wasps, woodlice, centipedes and spiders taken from webs as shown on the BBCs One Show when they filmed Natterer’s at the lake. One young is born in June and within four weeks becomes independent of its mother. The bats may be on the wing from February to December when they go to winter roosts, often individually, at the entrance to underground sites. Natterer’s have been shown to live for over 21 years.

Echolocation frequency of maximum energy (FM call) peaks at 46.9 kHz (range 36.0-66.8) with an inter-pulse interval of 80.1 ms (range 31.6-188.9) and call duration of 4.7 ms (range 1.9-7.1).

Normal weight 7-10g, Forearm length 34.4-44.0 mm, Fifth finger length 48-58 mm, Third finger length 65-74 mm.

Other identification features: S-shaped calcar.

Here is a list of all Natterer’s Bats known to have been ringed at the Bristol Reservoirs:

Ringing Data

Bibliography (sources of information):

    1. Bat Conservation Trust website.
    2. Dietz, C., Helverson, O. von, Nill, D. 2009. Bats of Britain, Europe and Northwest Africa. A&C Black Publishers Ltd., London.
    3. Fisher, J., Francis, J. & Jones, Prof G. The Bats of Britain (an online guide). University of Bristol, School of Biological Sciences website
    4. Russ, J. 2012. British Bat Calls A Guide to Species Identification. Pelagic Publishing, Exeter.

Last update: 27th August 2026