This was an online webinar, hosted by the Bat Conservation Trust, that aimed to provide an introduction to British bats and the types of survey that can be undertaken by Bat Conservation Trust volunteers.

The session was presented by Philip Briggs, with co-host Parvathy Venugopal. Below are some of my notes of this event.

Bat Conservation Trust

Discover your local bats

27 March 2024

Bats are in the order Chiroptera and are the only true flying mammals. With approximately 1400 bat species worldwide, there are 17 breeding species in the UK.

There are many places that bats can roost in buildings or in trees. They are protected by law, and there are multiple threats to their survival including:

Loss of roosts, loss of habitat, habitat fragmentation, pollution, predation, climate change.

They can be used as indicator species of a healthy environment e.g. Daubenton's bat is an indicator of good water quality.

Bats overview

The National Bat Monitoring Programme (NBMP) has been running since 1996. There are 4 summer surveys to chose from: sunset survey, roost count, waterway survey and field survey.

Sunset survey: Beginner survey, simply spend an hour looking for nocturnal wildlife. Starting at sunset, or if doing it at dawn, start an hour before sunrise.

Roost count: If you know of a roost, count the bats emerging at dusk.

Waterway survey: Using a bat detector select a 1km stretch of waterway, stopping at regular intervals and count Daubenton's bat passes.

Field survey: Using a bat detector select a 1km square then walk a triangular route. Whilst walking tune heterodyne for noctule and serotine; then at regular stops tune for pipistrelles.

Surveys

For identifying bats in flight, you can observe the flight pattern e.g. Noctules fly very high. Additionally, the frequency of the echolocation calls are also used. bat detectors that produce a spectrogram allow you to visualise the shape of these calls to aid in identification. 

Identification

As part of this webinar, I ordered an accompanying guide to identifying bats in flight (Bat Conservation Trust, no date) which provides illustrations of flight patterns and call parameters.

Screenshot of 'Discover your local bats' presentation, showing the flight pattern, outline and frequency of a noctule.

Reflection

This presentation provided a basic introduction to bats, and the types of surveys that volunteers can do for the Bat Conservation Trust. I felt that the main benefit for myself was the accompanying book that provides useful information for attempting to identify bats in flight by using flight patterns, peak frequency and other call parameters.

I would like to perform some bat surveys when I have the opportunity. 

Edit: Subsequent to this activity I attended a bat seminar and walk where I was able to use a bat detector (heterodyne) and also an Echo Meter Touch 2, which I really enjoyed.

References

Bat Conservation Trust (no date) Identifying bats in flight: An introduction to field techniques. Bat Consevation Trust.