Soprano Pipistrelle Emergence

The footage below, taken in July 2022 at a site in Dorset, shows a soprano pipistelle emerging 37 minutes before sunset – unusually early for an emergence. Best practice, according to the Bat Conservation Trust (BCT), is that ecological surveys for bats should start fifteen minutes before sunset – in which case, we would very definitely have missed this little fellow! (Bat Surveys for Professional Ecologists: Good Practice Guidelines (3rd edn)).

Species such as common pipistrelle and soprano pipistrelle emerge from their daytime roosts earlier than the larger bat species, especially if the weather is sunny and dry during the day. This is why our surveys start a minimum of 30 minutes before sunset, and then continue for 60-120 minutes after sunset (depending on the species we are recording) in order to gain an accurate log of the activity at any given roost.

The soprano pipistrelle is a ‘crevice dwelling’ species that will take it’s daytime rest tucked under roof tiles, in gaps around chimney flashing or under the eaves of buildings. The example below shows a soprano pipistrelle flying out from a small area of missing pointing at the edge of a slate roof.

Slow-motion footage of a soprano pipistrelle emerging from a gable-end, recorded on an infra-red camera.

Why do we use infra-red cameras?

Daniel Ahern Ecology Ltd has been using infra-red camera and illuminator equipment to support our bat survey work for several years now. Enhanced night-vision allows us to pinpoint areas of emergence and to record any individual bats that may have been missed by the naked eye. The company welcomes all improvements to best practice to ensure that the entire sector uses these devices. (See the Bat Conservation Trust’s publication: Interim guidance note on night vision aids).

Daniel Ahern Ecology

Home Farm House, Humber Lane, Tidworth, Wiltshire, SP9 7AQ
01980 842709
07880 551441

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