Leisler's bat

Description

The Leisler's bat is a medium-sized bat with a snout-vent length of 48 to 72 mm and a tail of 35 to 48 mm in length. The wingspan is 26 to 34 cm with an underarm length of 39 to 47 mm. Compared to the common noctule (Nyctalus noctula), it is clearly smaller, although particularly large females come close to especially small representatives of the common noctule with a minimum forearm length of 48 mm. Body weight is between 8 and 20 g and females are usually slightly larger than males.

In its physique and appearance, the Leisler's bat largely corresponds to the common noctule and differs from the latter, apart from its body size, mainly by its distinctly bicoloured dorsal fur. This consists of bicoloured hairs, which are dark to blackish brown at the base and distinctly lighter at the tips. The yellow-brown belly of the animal is slightly lighter than the back. In May and August there is a seasonal change of coat, which is associated with a slight change in coat colour. In summer the dorsal coat tends to be dark reddish brown to mahogany, the reddish tinge disappears in winter and the coat becomes dark grey to dark brown, and the ventral side is also slightly greyer than in summer. Juveniles are dark grey in their first year of life.

The wings are comparatively long and narrow, as in other noctule bats. The patagium is densely furred along the back and arms. The tail protrudes about one to two mm from the uropatagium. The ears are broad and triangular at the base, the ear tips are rounded. They have a size of 11.2 to 16.5 mm. At the outer edge the auricle has four to five transverse folds. The tragus is short and mushroom-shaped and thus corresponds to that of other noctule bats. Compared to the common noctule, the snout is conspicuously pointed with a slanted mouth.

Habitat

The species prefers open forests as habitat and is considered a typical forest bat. It uses deciduous forests as well as mixed and various coniferous forests as habitat. The habitats differ regionally in their forest composition; in Austria, for example, the bat prefers mainly mixed oak forests, while in other areas it is found in forests with a high proportion of beech, spruce and fir. The possible habitats are also diverse in terms of management form and range from structurally rich plenter forests to simple old-growth forests. The Leisler's bat needs tree hollows both as a nursery roost and as a winter habitat and therefore occurs most frequently in forest stands with a high proportion of older trees; alternatively, artificial roosts such as bat boxes or bird nesting boxes can also increase its attractiveness.

Hunting areas are pastures close to forests, water areas and rivers. Occasionally, the Leisler's bat is also found in towns and even in larger cities. In cities, its roosts are mostly in parks and only rarely in buildings.

The text is a translation of an excerpt from Wikipedia (https://de.wikipedia.org/wiki/Kleiner_Abendsegler). On wikipedia the text is available under a „Creative Commons Attribution/Share Alike“ licence. Status: 13 August 2021