Habits: Pipistrelles form summer nursing colonies and winter hibernation colonies that can contain up to 1,000 bats. They roost in trees, rock crevices, buildings, and haystacks. The small pipistrelle can fit in gaps just half an inch wide. From spring to fall the pipistrelle sleeps during the day. It feeds after sunset but occasionally appears during the day in midsummer. The bat is most active at dusk and just before dawn. Each bat spends two to five hours every day away from the colony making short feeding flights and stopping off at temporary roosts. An archway provides an ideal roost for a pipistrelle. During the summer males live together in small groups.

Hibernation: The pipistrelle goes into hibernation in October to avoid the cold winter. The colony gradually stops feeding and finds a sheltered site. During the next few months each bat uses up it fat stores to stay alive. After hibernation the bat weighs only a fraction of an ounce. The pipistrelle hibernates in quiet spots in large houses, church roofs, bell towers, gaps behind shutters, hollow trees, and rock crevices. The bat hangs or wedges itself head-down, gripping the surface with its feet.

The pipistrelle does not sleep as deeply as other hibernating mammals and it regularly awakens, often because it needs to expel waste. At other times, it is disturbed by other bats and wakes up. During winter warm spells it may temporarily come out of hibernation and fly around. Dense, warm fur protects the bat during the cold winter hibernation. Pipistrelles cling together for warmth during hibernation.

Breeding: The pipistrelles mate before hibernation in September, but the sperm does not fertilize the female’s eggs until spring. The young’s development depends on the weather and food supply. Poor conditions halt the development of the fetus. Female pipistrelles form roosting groups in early summer. They move apart from the roosting group to give birth but then carry their blind newborn back to the nursery group. The young develop rapidly and fly after about three weeks.

Food and Feeding: The pipistrelle mainly feeds on small flying insects, catching and eating them while in the air. It eats larger prey on a perch. The bat must eat several hundred insects every day to survive. The pipistrelle usually hunts in the same open area near a tree or building. It flies quickly and erratically, with rapid wing beats, dodging and turning in the air 20 feet above ground. The pipistrelle must perch to eat larger insects.

Key Facts:
Sizes:
Length: 1-2 in.
Wingspan: 7 ½ -10 in.
Weight: Up to ½ oz.

Breeding:
Sexual Maturity: Female, 1 year. Male, 2 years
Mating Season: Fall
Gestation: 44-50 days
No. of young: Usually 1
Weaning: 30-40 days

Lifestyle:
Habit: Nocturnal. Occurs in colonies up to 1,000. Hibernates in winter.
Diet: Small flying insects
Lifespan: Average 4-5 years

Related Species: There are 48 species of pipistrelle distributed throughout most of the world.

Distribution: Europe, except the far north, east across western Asia as far as Lake Baikal in the Soviet Union and down to Kashmir and the Altai mountain range.

Conservation: One of the more common bats across its range, the pipistrelle has recently suffered sharp population declines in some areas.

Features of the Pipistrelle:
Wings: Modified hands made up of a tough membrane stretched between the bat’s four digits and the feet.
Body: Small, mouse like body entirely covered with fur and supported by large wings.
Ears: Fleshy spike in the center of the ears is known as the tragus. Its shape varies between species.

Nature watch: Common throughout Europe, the pipistrelle lives in a wide range of habitats in both rural and urban areas. These include woodlands, wetlands, grasslands, farms, and gardens. It prefers open grassy areas surrounded by trees or bushes, but it also flies low over the water to feed on mayflies and insects