Tschuli Myotis

Natterer's bat is a medium-sized species and grows to a head and body length of 44 to 51 millimetres (1.7 to 2.0 in) with a forearm (elbow to wrist) length of 34–44 millimetres (1.3–1.7 in). It weighs between 7 and 10 grams (0.25 and 0.35 oz). The short, dense fur on the dorsal (upper) surface of head and body is greyish-brown while the ventral (under) surface is whitish-grey. The ears and the wing membranes are smoky grey. This bat can be distinguished from other similar species by the fact that the free edge of the interfemoral membrane between the hind limbs is wrinkled and fringed with stiff, curved hairs and the calcar, a spur of cartilage that supports the membrane, is shaped like a "S".

The Natterer's bat species complex has a western Palaearctic distribution and is native to most of Europe, parts of the Middle East and parts of northern Africa. Its range extends from southern Sweden, Finland and western Russia in the north to Ireland, the United Kingdom, Spain and Portugal to the west. It extends eastwards to Ukraine, western and southwestern Asia Minor, the Levant, the Caucasus region, the Kopet Dag Mountains in Turkmenistan, Iran and northern Kazakhstan. Its southern limit is Morocco and Algeria, southwards as far as the Atlas Mountains. Records from North Africa are few in number and the population there is likely to be small. Its historic range included Norway, in which it is now a possibly extirpated species. Despite the wide distribution of the species complex, genetic and morphological studies indicate that 'true' M. nattereri occur in most temperate zones in Europe and the Balkans. Natterer's bats native to other geographical areas have been reclassified as follows:

Though clarity has increased regarding the diversity of the Natterer's bat species complex, some populations in the Middle East still remain unclassified. It is found from sea level up to an altitude of about 2,000 metres (6,600 ft). It is found in forests, parkland, and in open countryside with scattered woodland. It roosts in holes in trees, buildings and nestboxes. …

Natterer's bat is nocturnal and insectivorous. It emerges at dusk to hunt for insects and uses echolocation to find prey and orient itself at night. Like many other species of bat, it emits sounds at too high a frequency for most humans to detect and then interprets the echoes created in order to build a "sound picture" of its surroundings. The frequencies used by this bat species for echolocation lie between 23 and 115 kHz and have most energy at 53 kHz. The individual signals have an average duration of 3.8 ms. The wide bandwidth of its frequency-modulated search signals enables it to detect prey only a few centimetres from vegetation and it does not use vision, olfaction or sounds emitted by its prey for this purpose. The bat feeds on the wing and it mostly catches insects in flight but it is also able to feed on prey items such as spiders and caterpillars dangling close to foliage on silken threads. During a study of the bat's diet, examination of droppings showed that it can also gather prey items from the ground. The diet was found mostly to consist of large Diptera (flies) but Trichoptera (caddisfly), Hymenoptera (bees, wasps, ants and hoverflies) and Arachnida (spiders and harvestmen) were also commonly eaten. …