Monitoring a Soprano pipistrelle maternity roost

Our staff are currently undertaking a large number of bat surveys and last night we discovered a major soprano pipistrelle Pipistrellus pygmaeus maternity roost in the roof of a private dwelling. We have attached photos of some of the bats emerging at dusk, and also of bat droppings recorded on a window ledge at the site. Click on the gallery below to view these photos individually.

Soprano pipistrelle is widespread species in Ireland and is regularly found roosting in buildings such as this one. The species is still common in Ireland, but has declined due to agricultural intensification both in Ireland and across Europe. Its reliance on buildings also makes it vulnerable to building works and roof treatments, and its conservation depends on tolerance and goodwill from the property owners where they occur. All species of bat and their roosts are of course also strictly protected in Ireland.

Soprano Pipistrelles form maternity roosts with large numbers of individuals (up to 1,500). There were several hundred bats using this roost we discovered last night, and we will be monitoring this site further next week.

Bat droppings on window ledge at the subject house

Bat droppings on window ledge at the subject house

During the summer, female soprano pipistrelles form maternity colonies – like this one – where they give birth to a single offspring in June/early July. For up to a month the juveniles are fed solely on their mother’s milk. When they are about a month old the young bats are able to fly and by six weeks they are able to forage for themselves.

ECOFACT is one Ireland’s leading independent provider of bat surveys and bat impact assessments studies

Meanwhile, male bats usually roost singly or in small groups during the summer months. During the mating period (July to early September) they defend their territories as mating roosts, attracting females by making repeated ‘songflights’ around their roost. Soprano pipistrelles usually feed in wetland habitats and also around woodland edges and hedgerows. This subject house was located in an upland area and adjoined a large coniferous forestry plantation. The bats feed mainly on small flies such as midges – which were very abundant last night!

Bats can be identified using bat detectors and soprano pipistrelles echolocate at a peak intensity of around 55kHz. This species can be distinguished by its call from the similar common pipistrelle Pipistrellus pipistrellus, which uses a call with a peak intensity of 45 kHz. We use both heterodyne and frequency division (Anabat) detectors during our surveys, and record the calls on the latter for subsequent analyses. An example of a soprano pipistrelle sonogram that we recorded last night on one of our Anabat bat detector units is given below. Using this approach we can always confirm our identifications in the office, and also have a full record of the survey which can be important for Environmental Impact assessment studies.

Anabat sonogram recorded of a Soprano pipistrelle recorded at this maternity roost

Anabat sonogram recorded of a Soprano pipistrelle recorded at this maternity roost

ECOFACT is one Ireland’s leading independent provider of bat surveys and bat impact assessments studies. We work on all types of projects from large wind energy developments, down to small farm building renovations. All our bat survey staff are fully trained, licensed and approved by NPWS, and are on the Heritage Council’s bat expert panel.

Further information

For further information on bats and bats surveys please follow the links given below:-

Also, if you have any queries regarding bats or bat surveys and assessments, please do not hesitate to contact us.

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