Just as Vera Lynn sang, the voices of nightingales are again being heard in Berkeley Square in central London over the hum of traffic and din of construction work.

The nightingale has virtually disappeared from Britain over the past 50 years, its population plummeting by 93% to fewer than 5,500 pairs. But now a chorus of nightingale events are being arranged by artists, musicians and filmmakers to raise awareness of the plight of one of the country’s most celebrated but endangered birds.

Birdsong was played on phones on Friday as the street artist ATM spent the day painting a nightingale in a gallery on the square, and more than 750 people attended a concert on Monday, when the folk singer Sam Lee and other musicians will duet with amplified nightingale song.

Let Nature Sing, a track of pure birdsong including the nightingale, has been released by the RSPB to highlight the loss of more than 40 million birds from the UK in 50 years.

The modest-looking nightingale’s remarkable, mostly nocturnal song has inspired writers ever since it was described by Pliny the Elder several thousand years ago. Romantic poets from John Keats to Samuel Taylor Coleridge feted this unobtrusive brown bird’s astonishing musicality.

Its song was played in Berkeley Square as ATM painted a nightingale on the tailplane of a Wellington bomber at an event organised by the makers of a new documentary, The Last Song of the Nightingale.

In 1924, the BBC’s first live-to-radio broadcast featured the cellist Beatrice Harrison playing a duet with a nightingale recorded in her garden in Surrey. The BBC continued this annual tradition until 1942, when the broadcast was famously abandoned when microphones picked up the sound of Wellington and Lancaster bombers en route to attack Germany, and the radio engineers realised the sounds could forewarn Hitler.

“When you’re out in the English countryside in spring and the blackthorn is in blossom, the nightingale’s song is just the most fantastic sound to listen to,” said ATM. “With a nightingale you never know what’s going to come next. They have a repertoire of 200 phrases and they surprise you all the time.”

Lee, who helped edit the RSPB single, is in the midst of a nightingale tour, with a sold-out festival in Fingringhoe Wick, Essex, on Saturday attracting more than 100 people travelling on free buses from London. Musicians including the harpist Serafina Steer and Cosmo Sheldrake played alongside nightingales singing at the nature reserve.

On Monday evening, folk singer Sam Lee will rework Vera Lynn’s classic song A Nightingale Sang in Berkeley Square at a free Extinction Rebellion event in the square. Photograph: Chris Lawrence/Alamy

Lee said the nightingale was the most inspiring of musicians.

“For me it’s pure song,” he said. “It’s an animal that is so utterly at one with music and the environment and using all the tropes and articulation and emotional capacity of a human musician, in the shape of a tiny brown feathered being. Its song is absolutely full of indulgence and decadence and serenity and sexuality and pleasure and connection and commonality.”

On Monday evening, Lee will rework the classic song A Nightingale Sang in Berkeley Square at a free Extinction Rebellion event in the square, after which the audience will be encouraged to disperse through the streets of London with the nightingales’ song playing on their phones.

Lee said it would be “a celebratory finale after the end of the Extinction Rebellion”, referring to the climate protests that blockaded junctions in London over the past two weeks. He added: “At this rate we’re going to lose our nightingales, and so many species are in massive decline. We have to start celebrating these species and the arts are a very important way of brokering awareness and creating an agency for change.”

The film-maker Luke Massey, who arranged the live art event with ATM, is making a documentary about the decline of the nightingale. He said: “Pliny the Elder describes nightingale song perfectly 2,000 years ago. The Owl and the Nightingale is [12th or 13th century – see footnote], then there’s Shakespeare and Keats and Coleridge. How can we go from loving these birds to the point where they are set to decline further in the next 10 years and could become extinct in England?”

ATM said he was convinced that nightingales did once sing in Berkeley Square. “It’s all about whether there was dense scrub in the square and I wouldn’t be surprised if there was one singing here 150 years ago.

“I lived in Berlin and the nightingale’s song was a common sound. Unfortunately the modern ethos of park-keeping is lawns and open spaces. People are frightened of the impenetrable places the nightingale needs.”

• This article was amended on 2 May 2019. A quote in an earlier version incorrectly said the poem The Owl and the Nightingale dated from the sixth century; the Middle English poem was actually written in the 12th or 13th centuries.