Nathusius' pipistrelle Pipistrellus nathusii

Nathusius' pipistrelle - click to enlargeNathusius' pipistrelle was only discovered to be breeding in Northern Ireland in 1997 and is therefore quite rarely encountered. Nathusius' pipistrelle is very similar to the other pipistrelle bats, but is slightly larger with shaggier fur. They emerge just after sunset and are found foraging along tree lines and woodland by water. In winter, Nathusius' pipistrelles hibernate. In Europe, this species is migratory. However, it is not known whether Northern Ireland's bats migrate.

SPECIES DESCRIPTION: Nathusius' pipistrelle is slightly larger than the other pipistrelle species found in Northern Ireland. The fur is a dull brown colour, often with paler tips giving a 'frosted' appearance. The ears, membranes and face are usually very dark, nearly black. They are very similar in appearance to the common pipistrelle and the soprano pipistrelle, but can be identified easily with a bat detector. Head and body length is about 45-55mm and the length of the forearm is 32-36mm. Weights of fully grown adults can vary from 3.6g to 5.9g. Bats emerge in early dusk, usually before the common and soprano pipistrelles and the flight is rapid - faster than the other two pipistrelle species, often with deep wing beats when flying in a straight line. In confined spaces it is not so manoeuvrable as the common pipistrelle. Flies 4-15m above the ground. Mating occurs from August to September and males are particularly vocal during this time. Fertilisation is delayed. Females form large maternity colonies during May and, in Northern Ireland, the males roost singly, often nearby. Young are born in June in maternity colonies situated in cavity walls of Victorian outhouses, both used and unused and under roof slates. Roosts found to-date are always located close to water. It is not known where this species hibernates or if it migrates.


© Jon Russ 2001. Text refereed by Angela Ross & Lynne Rendle.

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