Myotis nattereri

Sleeping Natterer's bat
Sleeping Natterer's bat
Sleeping Natterer's bat


Оccurs in a large part of Europe, the entire Mediterranean area and on Corsica, Sicily and Cyprus. From Asia Minor to the Middle East (Israel, Lebanon and Jordan) into Iraq, Iran, and Turkmenistan and North Africa.1 In Bulgaria it can be found in hilly and mountainous areas.

A medium – sized bat with long ears and a narrow muzzle. The ventral side is white to grey – white and is sharply demarcated from the brown – grey dorsal side. The face is brightly pink colored and bare. The tragus is slightly bent and longer than half the ear length. The tail membrane is supported by a long, S – shaped curved calcar. The wrinkled edge of the tail membrane is densely covered with two rows of short, curved bristles.

Usually 2 – 5 ms long frequency – modulated calls, which can start very high (100 – 150 kHz) and drop to approximately 20 kHz, or even 12 kHz. At this frequency, they reach the audible range of human hearing and it is possible to hear a very close – flying Natterer’s bat with the naked ear.

Forests and open woodland such as parks, traditional orchards and along water bodies. In Bulgaria prefers deciduous forests. In the Mediterranean area it can be found in forest – like biotopes in the broadest sense, such as olive groves or pastures with trees. This species is sedentary, some animals make shorter migrations. The nursery colony can use a complex of roosts sites in an area of up to 2 km2. Hunting grounds cover 170 – 580 ha.

Summer roosts are in tree holes, bat boxes and under the bark of the trees. In the Mediterranean area the roosts are found particularly in rock and wall crevices. Winter roosts are located in rock crevices, caves and rock storage tunnels.

Nursery colonies comprise of 20 – 50 bats and they are formed from May to September. Single males are often found in the nursery roosts, but they can also form their own colonies of up to 25 animals. The roosting sites are changed every 2 – 5 days.The area of this bat can be very large – to 4 000 km2 . Natterer’s bat swarm at caves from August, particularly in mid – to late September. The female gives birth to one young between the beginning of June and the beginning of July. The first flight of the young is after 20 days, and after four weeks they are independent. Mating takes place at the swarming sites and in the winter roosts. There is no data for winter roosts in Bulgaria.

The flight is manoeuvrable and can be slow. Usually this species flies close to vegetation. The prey is often picked off with the tail membrane . There is a suspicion that the bristles at the margin of the tail membrane function as sensory organs. Also echolocation helps with the location of the prey – spiders on a web, harvestmen and crane flies with their long legs, raising them above leaves.

Habitat fragmentation, the use of pesticides and the disturbance in roosts.

Christian Dietz and Andreas Kiefer (2014), “Bats of Britain and Europe”;

Vasil Popov, Atila Sedefchev (2003), “Mammals in Bulgaria”;

Vasil Popov, Nikolay Spasov, Teodora Ivanova, Borqna Mihaylova and Kiril Georgiev (2007), “Mammals important for conservation in Bulgaria”.