Nyctalus leisleri (Kuhl, 1817)
Pterygistes leisleri Kuhl: Buresch, 1917: 156-158; Vesperugo leisler K. et Bl.: Kovachev, 1925: 63-64.
Conservation status: in Bulgaria: Vulnerable VU [B1 b(i, ii, iv)], BDA-II, III; International: IUCN-LR/nt, BeC-II, BoC-II, HD-II, IV.
General distribution. Western and Central Europe, rare in the countries of the Mediterranean region, in the east to the state of Utar Pradesh in India, in the south to Northern Africa.
Distribution and abundance in Bulgaria. It has been found in 16 localities, most of which are at altitudes of under 800 m [1, 2]. Until 1985, 6 localities were known. Two of its localities in Northern Bulgaria (Bozhichen and Svalenik, Ruse region) are from owl pellets . It has not been found in a vast part of the territory of the country. The highest altitudes at which it has been found (1 500 m) are in the Central Balkan range, Pleven hut . More than half of its contemporary localities (6) are in Strandzha.
Habitats. A typical inhabitant of forest habitats in the low and middle mountainous belt. A flier of free spaces. In most parts of the continent it lives mainly in hollows of trees. In Eire many of its colonies are in human buildings (atticks of houses, churches, etc.). Most of its habitats are in large forest massifs or immediately close to them. In Central Europe it often settles in bat houses. In Bulgaria it has been found in bat boxes over the Sedemte Prestola monastery in the Western Balkan range and also in houses for birds around Chernomorets, to the south of Burgas. Probably it is found everywhere in the lowlands of Bulgaria, as has been established for Greece .
Biology. Understudied. It feeds on butterflies, beetles, lacewings, caddisflies and other insects. So far there has been no sure evidence of its breeding in Bulgaria. It is supposed that in the Balkan peninsula in the summer only male and non-multiplying female individuals are found . The species is considered to be migratory but the data about migration routes are few. Nursery colonies are formed most often in holes of trees at the end of April and the beginning of May. The females give birth at the beginning of June: one, sometimes two young.
Similar species. The greater noctule (Nyctalus lasiopterus) and the noctule bat (Nyctalus noctula), from which it differs with the smaller dimensions: the length of the forearm is under 46 mm.
Negative factors. Felling old trees and trees with hollows restricts the possibilities for finding appropriate roosts. In Bulgaria it has been found in owl pellets .
Conservation measures taken. The species is protected according to the Biological Diversity Act, EUROBATS and all international conventions (without CITES). One of its localities falls within the reserve Steneto, another is within the territory of the Central Balkans national park. In connection with the monitoring of bat houses, the species is included in the National System for Monitoring the Biological Diversity.
Conservation measures needed. Focused study on the distribution and the biology of the species. Development of a management plan for the forest species of bats.
References. 1. Benda et al., 2003; 2. Popov et al., 2006; 3. Mitev, 1995; 4. Ivanova, 1998; 5. Hanak et al., 2001.
Author: Boyan Petrov