Merlin has been trained to identify the songs of more than 1,300 bird species around the world

When Natasha Walter first became curious about the birds around her, she recorded their songs on her phone and arduously tried to match each song with online recordings. After a friend recommended Merlin Bird ID, a free app, she tried it in her London garden and was delighted to discover the birds she assumed were female blackbirds – “this is how bad a birder I was” – were actually song thrushes and mistle thrushes.

“I’m obsessed with Merlin – it’s wonderful and it’s been a joy to me,” says Walter, a writer and human rights activist. “This is what AI and machine-learning have been invented for. It’s the one good thing!”