16.

Leisler’s Noctule

Nyctalus leisleri

French: Noctule de Leisler / German: Kleiner Abendsegler / Spanish: Néctulo pequeno

Other common names: Leisler’s Bat, Lesser Noctule

Taxonomy. Vespertilio leisler: Kuhl, 1817,

Hanau, Hessen, Germany.

Nyctalus leisleri 1s sister to N. azorewm, with very limited genetic distinction, although N. azorewm 1s morphologically and ecologically distinctive and has been isolated on the Azores for enough time to permit some genetic variation between differ ent island populations. The insular subspecies verrucosus has sometimes been considered a distinct species but is here included in N. leisleri, based on cranial morphometrics and genetic data. Two subspecies recognized.

Subspecies and Distribution.

N.l.leisleriKuhl,1817—throughoutEuropefromIreland,GreatBritain,andIberianPeninsulaEtoSWRussia,Caucasus,Turkey,andNIran,andanisolatedpopulationinSSweden,aswellasCorsica,Cyprus,W&NCrete(recordsmaybeaccidentalmigrants),andCanaryIs(TenerifeandLaPalma),NAfricainNMorocco,NAlgeria,andarecordfromNELibya,andSCAsiainNEAfghanistan,NPakistan,andNWIndia;possiblyalsofoundonRhodesIoffWTurkeybutrecordthereisprobablyavagrantfrommainlandpopulations.

N. l. verrucosus Bowditch, 1825 — Madeira I.

Descriptive notes. Head—body 48-72 mm, tail 35-48 mm, ear 11-16 mm, hindfoot 9-10 mm, forearm 35-46 mm; weight 8-20 g. Dorsal pelage of Leisler’s Noctule is golden yellowish brown (hairs dark brown at base, becoming golden brown toward tip), ventral pelage is a lighter yellowish (hairs blackish brown with brown tip). Face, ears, and membranes are dark brown, and tail extends a few millimeters past uropatagium. Muzzle is short, with large glands between nostrils and eyes, and ears are short and triangular, with 4-5 folds on outer edge. Tragus is very short and rounded, mushroom-shaped,as is characteristic of the genus. Wings attach at ankle, and calcar reaches halfway to tail. Postcalcarial lobe is wide with visible T-shaped piece of cartilage. Skull is small, and rostrum is broad; lambdoid crest is weakly developed, and there is no sagittal crest; dentition is moderately weak; lower molars are nyctalodont. Chromosomal complement has 2n = 46 and FNa = 50.

Habitat. A variety of habitats including temperate deciduous and coniferous forests, agricultural regions, and river valleys. In North Africa, the species is found mainly in oak forests (as well as juniper-cypress forests) at elevations of 400-900 m. Leisler’s Noctules have been found at elevations from sea level to ¢. 2400 m throughout their range.

Food and Feeding. Insectivorous. Leisler’s Noctules feed on a variety of medium-sized flying insects, their diet consisting primarily of lepidopterans and flies (particularly Nematocera) in most parts of their range, although this is variable. They are also known to feed on a variety of other insects, including Trichoptera, Neuroptera, Coleoptera, Ephemeroptera, and Hymenoptera . Leisler’s Noctule is a fast aerial hawker, generally forages above or along the canopy of forests and along vegetation or above river valleys and other open areas.

Breeding. Mating occurs in late summer before hibernation in late August to September and the species exhibits delayed fertilization. Parturition occurs after hibernation. Young are born around mid-summer, in June and July; lactation can occur until mid-July, with the first volant young usually recorded in July, although births have been recorded in May, with volant young in June in Morocco. Litter size is 1-2 (two is commoner). Leisler’s Noctules can apparently live up to nine years.

Activity patterns. Roosts during summer are found in tree holes and rock crevices, as well as in buildings and other man-made structures, whereas in winter they are mainly in tree holes and occasionally in underground sites (e.g. tunnels and animal holes) or buildings. Leisler’s Noctule is largely nocturnal, leaving the roost after dusk and foraging throughout most of the night, going back to the roost ¢.30 minutes before dawn. It forages in two periods, one just after dusk and the other before dawn. It uses temporary night roosts between the two foraging bouts throughout the night; these are often in buildings. Leisler’s Noctules have been observed flying during the day, but this is probably only out of necessity. They are active throughout summer but enter hibernation, usually starting around mid-August to September and ending during spring, around March or April. In Morocco, the hibernation period is shorter, and individuals leave hibernation earlier. Activity peaks before and after hibernation, which is also when migrations generally occur. There are two types of search-phase calls, a QCF call shape with start frequencies of 22-26 kHz and call durations of 15-25 milliseconds, and a shallow FM call shape with start frequencies of 26-30 kHz, end frequencies of 25-26 kHz, peak frequencies of 25-26 kHz, call durations of 7-15 milliseconds, and intercall intervals of 220-550 milliseconds. Predators include diurnal raptors such as peregrine falcons (Falco peregrinus), Eurasian hobbies (F subbuteo), and common kestrels (F tinnunculus).

Movements, Home range and Social organization. Most populations of Leisler’s Noctule in central and eastern continental Europe are highly migratory and will travel hundreds to over a thousand kilometers. Most bats banded in Germany moved in a southwest direction. Many island and southern populations, where winter is less severe, are typically non-migratory, but there are records of individuals migrating within and between Ireland and Great Britain. Migration generally occurs after leaving hibernation in spring (March—May) and before entering hibernation in late summer and early autumn (August—early October); young are often born in the north, with hibernation generally occurring in the south. Some island records may be attributed to vagrants (e.g. on Rhodes and Crete). The longest recorded movement was of a female which traveled 1567 km from Germany to Spain. Average foraging area is ¢.7-4 km? but can be up to c.18-4 km*in southern UK. Although notterritorial throughout much of the year, males become very territorial during the mating season, when they form small mating harems in roosts of up to nine females. Roosts in summer consist mostly of maternity colonies with females and young, and bachelor colonies for males. Maternity colonies generally comprise c.10-50 individuals, but roosts of up to ¢.1000 individuals have been reported in Ireland. Males and immatures roost either alone or together in smaller roosts.

Status and Conservation. Classified as Least Concern on The IUCN Red List. Leisler’s Noctule is widespread and common throughout parts ofits distribution (particularly Ireland), although it is considered rare in many regions, and has become locally extinct in parts of central European Russia. The species may be threatened by the destruction of roosts in trees and buildings, as well as general loss of habitat. In Italy, introduced rose-ringed parakeets ( Psittacula krameri) have been recorded killing a roosting Leisler’s Noctule.

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