Nyctalus leislerilesser noctule

Geographic Range

Nyctalus leisleri occurs throughout much of Europe and the Middle East. It ranges from the Mediterranean Sea north to Ireland, England, and central Scandinavia and from Portugal east to the Caspian Sea, western Russia and Iran. It is also known in Algeria and Libya in north Africa along the Mediterranean. Throughout its range it is relatively rare except in Ireland, where it is the third most common bat species. (Schober, 1997; Stebbings, 1986; Stebbings, 1988)


Leisler's bats inhabit open deciduous and coniferous forests throughout most of their range. They appear to prefer old growth forest because they requires hollow trees for roosting and hibernation. Parks and estates with ancient trees can provide appropriate habitat. However, Nyctalus leisleri can also be found in agricultural and suburban areas where it utilizes buildings and bat houses as roosting sites. It will forage over many adjacent types of habitat including fields and open water.

This species is migratory and is apparently willing to fly over inhospitable habitat, as evidenced by an individual that was found dead on a glacier at 2600 m. (Schober, 1997; Shiel, et al., 1998)

  • Range elevation
    0 to 2600 m
    0.00 to 8530.18 ft

Physical Description

Nyctatus leisleri is a medium to small bat with a wingspan of 260 to 320 mm. Overall length is 83 to 113 mm and weight is between 11 and 20 g. The ears are low and rounded with a mushroom-shaped tragus. This species has somewhat long fur that is dark rufous brown on the back and lighter brown on the ventral side of the body. The dorsal fur is distinctly two-toned, being darker at the base. The face, ears and wing membranes are dark brown to black. The underside of the wing membranes are furred along the body and up along the arms to the fifth finger, hence the older common name 'hairy-armed bat'. The tail membrane extends to the ankles which have well-developed calcars. The tail is short and barely protrudes beyond the membrane. (Schober, 1997; Stebbings, 1986; Stebbings, 1988)

  • Range mass
    11 to 20 g
    0.39 to 0.70 oz
  • Range length
    83 to 113 mm
    3.27 to 4.45 in
  • Range wingspan
    260 to 320 mm
    10.24 to 12.60 in


Male Nyctalus leisleri attract potential mates to breeding roosts by vocalizing and aquire harems of up to 9 females. (Schober, 1997)

Nyctalus leisleri mates in late August or September and again in the spring. Males defend breeding roosts where they may aquire a harem of as many as 9 females. Females gather in maternity colonies where they give birth to 1 or 2 young in late spring. Only one litter is produced per year. Little is known about the specifics of development, but young can fly 30 days after birth. (Schober, 1997; Shiel and Fairley, 1999)

  • Breeding interval
    Nyctalus leisleri breeds twice yearly.
  • Breeding season
    Mating occurs in the fall and again in the spring.
  • Range number of offspring
    1 to 2
  • Average number of offspring

Female Nyctalus leisleri raise their young in maternity colonies and provide all care for the young after they are born. This includes providing milk as well as possibly transporting young between roosts. (Stebbings, 1986; Stebbings, 1988)


Little is known about the lifespan of Nyctalus leisleri. One individual is known to have lived 9 years in the wild, but other bats in the family Vespertilionidae can live several decades, so this may be a low estimate of the average lifespan. (Schober, 1997)

  • Range lifespan
    Status: wild
    9 (high) years
  • Range lifespan
    Status: captivity
    1 (high) years
  • Average lifespan
    Status: captivity
    16 years


Nyctalus leisleri has wings that are relatively long and narrow. This morphology is known as high aspect ratio and allows for great speed and endurance but less maneuverability in flight. Endurance is important to N. leisleri since this species is migratory (at least in eastern Europe) and has been known to travel 810 km during a migration. This species hibernates from late September to early April. Nyctalus leisleri is colonial, with as many as 500 individuals sharing a maternity roost, though 20 to 50 individuals is more common. Nyctalus leisleri becomes active early in the evening at or just after sunset. Like other Nyctalus, this species may have two periods of peak activity for a few hours at dusk and at dawn, but is known to forage all night. (Nowak, 1994; Schober, 1997)

Home Range

Nyctalus leisleri may travel up to 10 km from the roost to forage. (Schober, 1997)

Communication and Perception

Nyctalus leisleri communicates intraspecifically with a number of different vocalizations. Males produce a 'cheeping' call from their mating roosts or in flight to attract females. In maternity colonies, females communicate with each other and their offspring with a variety of squawks, cheeps and trills. In flight Nyctalus leisleri produces complex, songlike calls that may allow bats to identify other individuals and may be used in mate recognition or defense of foraging patches.

While in roosts chemical cues are also important and probably help females identify their offspring. (Pfalzer and Kusch, 2003)

Food Habits

Nyctalus leisleri feeds primarily on small to medium-sized flying insects. It forages at heights up to 150 m, using long-distance echolocation to find prey items. Larger insects are caught individually in flight by aerial hawking. Leisler's bats are adapted for speed, not maneuverability, so they do not glean insects from stationary objects. Nyctalus leisleri is also not thought to be maneuverable enough to capture individual smaller insects. It has instead been observed to fly through swarms of such insects, probably capturing many at one time. (Russ, et al., 2003; Shiel, et al., 1998)

The specific diet of this species varies depending on local habitat. In Ireland, where forests are rare, Nyctalus leisleri forages primarily over agricultural areas. As a result, more than 20% of its diet is composed of a single species, the yellow dung-fly (Scathophaga stercoraria), which feeds on the dung of farm animals. Other important foods in pastoral areas include crane flies (Tipulidae), wood gnats (Anisopodidae) and cockchafer beetles (Scarabaeidae). Near water midges (Chironomidae) compose up to 25% of the diet. In wooded areas moths (Lepidoptera), wasps (Ichneumonidae) and lacewings (Chrysopidae and Hemerobiidae) are important prey along with a number of other insects. Non-insect invertebrates such as spiders are also sometimes eaten. (Shiel, et al., 1998)

  • Animal Foods
  • insects
  • terrestrial non-insect arthropods


Little information is available on predators of Nyctalus leisleri.

Ecosystem Roles

Nyctalus leisleri is rare throughout its range so its role in the ecosystems it inhabits is somewhat limited. Colonies may be locally important predators of flying insects.

Economic Importance for Humans: Positive

Nyctalus leisleri feeds on many insects that are considered pests or annoyances to humans.

  • Positive Impacts
  • controls pest population

Economic Importance for Humans: Negative

In some parts of its range Nyctalus leisleri roosts primarily in buildings because of an absence of suitable hollow trees. This habit may annoy human inhabitats, though the species does not roost in large enough numbers to physically damage the structure.

Conservation Status

Nyctalus leisleri is considered rare throughout its range and is protected by local laws throughout Europe. Its preferred forest habitat is patchy throughout its range. Additional lost of forests or the removal of dead trees can only reduce this species' chance of survival. Humans can help provide more habitat for Nyctalus leisleri by installing bat houses or tolerating their presence in buildings.


Matthew Wund (editor), University of Michigan-Ann Arbor.

Sean Zera (author), University of Michigan-Ann Arbor, Phil Myers (editor, instructor), Museum of Zoology, University of Michigan-Ann Arbor.



living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map


uses sound to communicate


living in landscapes dominated by human agriculture.


young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.


Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.


an animal that mainly eats meat


uses smells or other chemicals to communicate


used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.


active at dawn and dusk


The process by which an animal locates itself with respect to other animals and objects by emitting sound waves and sensing the pattern of the reflected sound waves.


animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females


union of egg and spermatozoan


forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.


the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.


An animal that eats mainly insects or spiders.


makes seasonal movements between breeding and wintering grounds


having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.


active during the night


having more than one female as a mate at one time


Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

seasonal breeding

breeding is confined to a particular season


reproduction that includes combining the genetic contribution of two individuals, a male and a female


associates with others of its species; forms social groups.


living in residential areas on the outskirts of large cities or towns.


uses touch to communicate


that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).


Living on the ground.


uses sound above the range of human hearing for either navigation or communication or both


uses sight to communicate


reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.


Nowak, R. 1994. Walker's Bats of the World. Baltimore: Johns Hopkins University Press.

Pfalzer, G., J. Kusch. 2003. Structure and variability of bat social calls: implications for specificity and individual recognition. Journal of Zoology, London, 261: 21-33.

Russ, J., M. Briffa, W. Montgomery. 2003. Seasonal patterns in activity and habitat use by bats (Pipistrellus spp. and Nyctalus leisleri) in Northern Ireland, determined using a driven transect. Journal of Zoology, London, 259: 289-299.

Schober, W. 1997. The Bats of Europe & North America: knowing them, identifying them, protecting them. Neptune City: T. F. H. Publications.

Shiel, C., P. Duvergé, P. Smiddy, J. Fairley. 1998. Analysis of the diet of Leisler's bat (Nyctalus leisleri) in Ireland with some comparative analyses from England and Germany. Journal of Zoology, London, 246: 417-425.

Shiel, C., J. Fairley. 1999. Evening emergence of two nursery colonies of Leisler's bat (Nyctalus leisleri) in Ireland. Journal of Zoology, London, 247: 439-447.

Stebbings, R. 1986. Distribution and Status of Bats in Europe. Huntingdon, Cambridgeshire: Institute of Terrestrial Ecology.

Stebbings, R. 1988. The Conservation of European Bats. London: Christopher Helm.