Nathusius Pipistrelles

created July 2oo8
Updated July 2019

Pipistrellus nathusii (Keysering & Blasius 1839)

Nathusius’ pipistrelle is a rarely recorded bat in Great Britain and Ireland. Nathusius’ pipistrelles a small species found from western Europe to Asia Minor. . Click here for Jon Russ’ distribution map. In recent years, there have been an increase in the number of Nathusius’ recorded as more bat groups have gone hunting for them

In September 2009 we did get a chance to see one first hand, when we had a chance to see this Nathusius in care with the Herts and Middlesex group.

As Jon Russ says

Photo Nick Tribe

“Nathusius’ pipistrelle is a small species in comparison to other UK and Irish species. The upper fur is longer and shaggier than that of soprano and common pipistrelles, occasionally with pale frosted tips, but generally mid-brown. The under fur distinctly pale. The face, ears and membranes generally dark. Ears are medium sized and rounded – slightly longer than broad withal tragus that has a distinctly blunt rounded tip, about four times as long as broad and curved forward; The calcar reaches about half way to tail and a distinct post-calcarial lobe is present. The thumb has a claw that is equal to or greater than the width of closed wrist. The dorsal surface of the tail membrane is well haired on the basal half and beside the tibia. The fur on the underside of the tail membrane sometimes extends obviously along forearm to wrist ( based on Greenaway & Hutson, 1990).

Photo Nick Tribe

A general guide is to calculate the ratio between the length of the forearm and the 5th digit (i.e. 5th digit divided by forearm). If the resulting value is greater than 1.25 it’s usually a Nathusius’ pipistrelle. “

What was most obvious was how shaggy it’s fur was, the shape of its muzzle and the fact that the fur covered the tail membrane

Photo Nick Tribe

Until recently we had only one confirmed record dating back to 2005, but had six records in 2007 and now hear them regularly at several sites. Five of the six were found over water These were widely spaced which is not surprising as these bats are known to cover long distances.
In May 2010 we got a very clear recording of a Nathusius at Priory Country Park. This is the third time we have heard Nathusius here . Interestingly the other two records were in September.

Nathusius pipistrelle. Photo Bob Cornes

In 2013, we hit gold when we managed to catch a male Nathusius in Swineshead Wood. This male may have just been passing through, but we were very excited to find him and will be going back to investigate further.He may not have been a resident, but just passing through. We know that Nathusius migrate long distances. Friend of the Bedfordshire Bat group (and the discovererer of our Nathusius) is heading up a national research project on Nathusius and has been ringing bats at Blagdon Lake in Somerset, one of which was found in Holland http://www.bats.org.uk/pages/amazing_journey_for_a_tiny_bat.html

Pipistrelles have a distinctive way of flying and are the bats you are most likely to see, They have a swooping , fluttering flight and often fly in circles following the same route over and over again,but you can’t separate the three species on the basis of flight pattern.

Things get easier if you have a bat detector but it is still not straightforward. Nathusius’ Pipistrelle are not the easiest bats to identify and we are grateful to Jon Russ for his help in confirming recordings. A rule of thumb is that if the peak frequency is below 40KHz it might be a Nathusius , but might not be, and the social calls are even worse to disentangle.

In 2016 we found a pair of Nathusius in a bat box together at Priory Park. The male looked very pleased with himself.The female more coy.