Millions of acoustic recordings of high-frequency bat calls have been decrypted to reveal the number of species in the Bailiwick.

Since 2021, 150 volunteers spent more than 2,400 nights investigating the Bailiwick’s only flying mammal.

They gathered more than 3 million acoustic recordings of high-frequency bat calls and then used an automatic classifier to identify the species - discovering 13.

This citizen science research project is part of a four-year partnership between the British Trust for Ornithology and the States Agriculture, Countryside and Land Management Services.

Natural Environment Officer, Emily Coule, says it has been amazing to see so many people getting involved in such an important study:

"It’s been amazing to see the effort that has been put in by volunteers. We are really thankful for everyone that’s taken part and their enthusiasm.

Bats are one of those cryptic species because they're around at night and we don't really see them.

So the Bailiwick Bat Survey has been a really good opportunity to learn more about them.

Bats are a really important part of our ecosystem, they act as an indicator species, so they can give us information on the wider health of the ecosystem because of their very varied lifestyle."

She says the team didn't know what number to expect:

"I think thirteen is a good number.

Some of them are going to be resident which means they are here year-round, whereas others are going to be migrating so they might be coming in from France and all parts of Europe - coming to Guernsey for winter or maybe for their summer holidays."

The 2023 survey begins in April with volunteers welcome to get involved.