Nyctalus noctula
noctule

Most widely distributed vespertilionid bat, common throughout Europe, most of temperate Asia to Japan and Burma, Oman, Viet Nam, Taiwan, Algeria, and possibly Mozambique and Singapore.

Noctule bats are generally reside in forests but may forage in open areas and dwell in or near human habitation. Roosting sites include hollow trees, buildings, and caves.

Colors range from golden to dark brown above and usually pale brown below. Head and body length is 50-100 mm, tail length is 35-65 mm, and forearm length is 40-70 mm.

One litter 1, 2, or (rarely) 3 young are born per female between May and June, although breeding occurs in both September and the spring. Two young are often born in areas where winters are more severe. Females have been found to mate in captivity when 3 months old; gestation is 50-70 days. Males mate during their second autumn, when 15 months old.

Nyctalus noctula flies early, with quick turns. Its voice is described as sharp, stacatto cries or prolonged trilling similar to the song of a bird. Pregnant females roost in trees and buildings in groups of as many as 400 bats until after their young are weaned. During this time, males leave and become solitary. In early autumn, males congregate and set up territories in hollow trees. Females then aggregate at these sites and enter transient harems for mating.

Noctule bats generally have two main feeding flights of one or two hours duration, one in the early evening and the other ending just before sunrise. These bats eat winged ants, moths, and other insects, but are particulary fond of beetles. One instance of Nyctalus noctula capturing and eating house mice (Mus musculus) was observed.

Noctule bats have been infected in the laboratory with the plague-causing bacteria Yersinia (=Pasteurella), which points to some pathological implications for humans. They may also be a source of transmission for Borrelia recurrentis (a bacteria causing relapsing fever in humans), when humans are parasitized by ticks and body lice that have previously parasitized the bats.

Nyctalus noctula numbers are declining in Europe due to the elimination of their natural habitat, roosting trees, and insect prey.

Nyctalus noctula is migratory, traveling south-southwest to hibernate in caves and traveling a range of 80-750 km north-northeast to summer roosting sites. Not all individuals of a population migrate; some may overwinter in a hollow log or woodpecker hole. The longest journey recorded for Nyctalus noctula is 2,347 km.