Pipistrellus pygmaeus (Leach, 1825)
Vespertilionidae

Least Concern

Description

One of the smallest European bats from the Vespertilionidae family, with a head-body length between 36 to 51 mm, a wingspan of 190 to 230 mm, a forearm length between 27 and 33 mm, a tail between 37 and 48 mm and a weight of 4 to 7 grams. The fur is brown with the ventral part slightly lighter, with a sandy or beige colouration. Juveniles present a more uniform colouration than adults, usually greyish brown.

It can be differentiated from it's sister species, the common pipistrelle (Pipistrellus pipistrellus), because the Soprano pipistrelle has a lighter and more pink skin colouration around the eyes, snout and at the base of the ears. Another distinctive trait is that during mating season buccal glands turn bright orange. Similarly, both males and females present a yellow-orange colouration in their genitals.

Distribution

The distribution of this bat is mainly around the Mediterranean Sea, and it includes central and south Europe, Corsica, Sardinia and Sicily, and up to Great Britain. It's northern limit is in southern Norway, extending a little further than the common pipistrelle. In western Asia and eastern Europe it is found in Ucraine, Cyprus and the Caucasus, but it is absent in Crete.

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Roosts and phenology

Breeding colonies of this species can be composed from tenths of individuals (15-20) up to hundreds (900 in Germany). One of the largest breeding populations in southern Europe can be found in the Ebro Delta, with a colony of more than 1,000 individuals (ChiroBoxes). Sometimes they can share their roosts with other species like the common pipistrelle (Pipistrellus pipistrellus) or the Nathusius' pipistrelle (Pipistrellus nathusii). Generally these breeding colonies are found in cracks in buildings, under roof spaces, expansion joints, rock crevices, tree holes and bat boxes. These colonies usually form in late spring and females give birth at the begining or middle June. Juveniles start flying after 3 to 4 weeks and abandon the colony after one and a half month. They reach sexual maturity in autumn.

It is considered a sedentary species, as they only perform short movements during migration to get to/from wintering and breeding roosts. Yet, in Europe movements of up to 1,280 km have been registered. In southern Norway they are known to form concentrations of up to 2,800 individuals, probably indicating a hibernation colony.

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Habitat and diet

This species is completely adapted to humanized environments, even if it can also be found in forests, pastures, meadows and many other habitats. It has a clear preference for wetlands, such as marshes, litoral areas, riparian habitats and any riverine areas, avoiding agricultural areas and great field extensions. Depending on season and latitude, habitat selection can vary significatively. During breeding season wetlands become their main feeding grounds. In the Mediterranean and close to the Black Sea, they usually hunt in ponds, lagoons and coastal areas.

The diet of this species is mainly composed of small insects such as Dipterans (as Chironomids) and Hymenopterans, as well as Trichopterans , Coelopterans and Homopterans. They are extremely agile bats and can hunt under tree branches emerging fromt the water surface, in small forest clearings and above small water bodies. They generally concentrate their foraging activity during the first hours (1-2h) after sunset. Movements to the foraging grounds can vary a lot, but they are generally around 4-10 km from their roost. In Great Britain they can perform 1.7 to 10 km movements from their roost, while in Norway they can move up to 12 km and 800 m of altitude.