How to organise a Big Bat Count

As part of the Great Somerset Wildlife Count, the bat group can help people to find and count the bats of their local area with an innovative community mapping project.

So if you are a community group (wildlife, gardening, church, guides ..etc), or just a group of friends or neighbours, in Somerset who would like help to do a Big Bat Count on your patch then please do get in touch –

We can then reserve a provisional date for your bat count, which will enable you to recruit your teams.

How many people do we need?

Between 6 to 60 adults.

The bat count works best with small teams of between 2 to 6 adults who know each other, each hunting for bats in a defined area. Children are welcome if each is supervised. The Bat Group have ten sets of kit, so a successful bat count can be run with between 3 teams of 2, right up to 10 teams of 6 adults.

When should we do our Big Bat Count?

Bats hibernate overwinter, hence even in April, on a cold night they may not come out. Hence the best times for a count are:

  • First three weeks of May – sunset varies from 8:30 to 9:00PM
  • August through to mid September – sunset varies from 9:00 back to 7:30PM

It is very possible to do a count in June or July, however sunset can be very late from 9:00 to 9:30PM, which can make it a very late night.

How does it work?

A bat group member will bring the kit along at the start of the count, and give a quick briefing to the teams.

Teams of people cover different parts of a local area, with bat detectors that allow them to, listen to, and automatically identify the species of bat making their echolocation calls.

The teams record their bat observations on their phones using an online bat count map in the iNaturalist app. The count lasts for 90minutes after sunset.

As the count organiser, what preparation do I need to do?

To run a successful Big Bat Count there are several areas of preparation for you to cover:

Recruit your teams!

This might be within your community group, or perhaps by posting to a local area FaceBook group. There of lots of ways, but the key is to have a list of groups of people who want to help.

Define your teams survey areas

You know your local area! Where will your teams be looking? Define areas for each team that are easy to walk around in an hour. This could be as simple as marker pen circles on a map. So long as every team has an area, and knows where to go, that is fine.

Prepare your teams

Before the count you need to ask your teams:

  1. At least one adult (hopefully more) from each team should install the iNaturalist app on their internet-enabled phone, and create an iNaturalist account.
  2. Ask them to search for the “Somerset Big Bat Count” project in iNaturalist, and join that project.
  3. It helps with both pre-event communications, and on the night, if you sign everyone up to a WhatsApp group for use on the night’s count. A email group/list could also be used. This can help in case you need the cancel the event at short notice due to weather, or other unforeseen circumstances.

Safety Aspects

Familiarise yourself with the safety aspects of the Big Bat Count, including the SBG Risk Assessment for Big Bat Counts and default safety briefing.

Ensure your local policing team are aware of the count in advance, this can be done online.

Take the standard Big Bat Count safety briefing and amend it to include the local contact numbers and the Police reference number you have obtained. Ensure participants have seen this safety briefing.

Make arrangements for the count night

Organise a central place to meet, and from where the kit can be handed out and collected. A well-lit place for the briefing and debrief is useful.

Anything else?

That’s it really. With the preparations in place hopefully, the count should run itself on the night.

A bat group member will bring the equipment to the count, and help with the briefing of the teams. Then later in the night, everyone can see all the results in real-time on the iNaturalist map.

Big Bat Count


SERC logo

The Somerset Bat Group is grateful to the Somerset Environmental Records Centre (SERC) for funding the new equipment used in the Big Bat Counts.