THE nightingale, famous for its beautiful singing, is in a perilous decline.

Wandering Wiltshire’s woods and lanes these long May evenings, your chances of hearing its legendary song are strikingly low.

For centuries, poets and authors have written of the bird’s springtime singing, late into the night when other birds are silent. From Chaucer and Milton to Keats, it has become a symbol of loneliness, and melancholy and romantic love, and these longer, warmer evenings create the perfect condition for a nightingale serenade.

In years gone by, you might hear one singing in a thicket or a wood, in a May evening. They have been reported at Coate Water in Swindon in the past. The town even has a Nightingale Lane in South Marston. But the number of nightingales returning to the UK has declined to a level where the bird is at risk of disappearing in this country.

With just 5,500 singing males reckoned to be left in the UK, a Nightingale Festival is highlighting the threat to the bird. Over the next six weeks, the National Nightingale Festival feature events in 22 locations around the country, giving people a chance to hear the evocative song of the elusive bird.

Matt Prior, from Swindon, of the Wiltshire Ornithological Society, said the best chances to hear a nightingale locally were at Lake 74 at the Cotswold Water Park, where a nightingale has been heard in recent years. Nightingales have also been monitored on Salisbury Plain, and heard in Westbury.

“They used to be much more common,” Matt said. “There are still a few around but there has been a decline of about 90 per cent over the last 30 years.”

He said the reason for the decline in the number of nightingales migrating to the UK was not clear.

“We are at the edge of their range,” he explained. “They are a warm country bird. There are lots in Spain.”

Matt said there was a theory that the decline here was because of the increase in browsing deer, because nightingales nest on the ground amid brambles and bushes and deer were nibbling away their cover. Another possibility is that changes of land use in West Africa, where many nightingales spend part of the year have disrupted the birds.

He said the entire life cycle of the nightingale needs to be investigated to work out why fewer birds visit the UK in the summer months, beyond the regional level, to gain a global perspective.

“The British Trust for Ornithology is doing a lot of research work, working with Ghana and using trackers on birds,” Matt said.

“Nightingales are not a very long-lived bird – about seven years, compared to a reed warbler which can live 13 years.”

Nightingales feature in several famous poems, including Ode to a Nightingale by John Keats, as well as in many pieces of music, such as Beethoven’s Pastoral Symphony, where he even wrote the bird’s name in the score.

Its complex and varied song is often used as a metaphor for beauty, love and poetry itself, and in the past the bird was referred to as a female when it is actually the male which sings. Those that sing through the night are thought to be trying to serenade migrating females down from the sky.

In 2009, some British nightingales were fitted with tiny geolocators and when one was recaptured the following year, it turned out the bird had travelled 3000 miles to wintering grounds in Guinea, West Africa.

The date nightingales arrive in the UK is getting earlier, probably due to climate chance. For example, the average first nightingale record in Sussex during 1962-93 was April 13 but in 2006-15 was April 4.

In the 19th century, bird catchers caught large numbers of nightingales for the caged bird trade to try and ‘capture’ its song. Most quickly succumbed in captivity and those that survived until autumn often killed themselves, dashing against the cage bars as they tried to follow their migratory urge. The first live radio broadcast of birdsong was of a nightingale in concert with the cellist, Beatrice Harrison, on May 19, 1924. This and repeat performances in subsequent years were so successful that Beatrice received 50,000 fan letters.

Nightingales are rather drab brown birds but they have an rich repertoire, and are able to produce over 1,000 different sounds, compared with just 340 by skylarks and about 100 by blackbirds.

The Nightingale Festival was organised by the RSPB, the wildlife trusts, Knepp Estate and folk singer, song collector and nature lover Sam Lee. Sam set up a project called Singing with Nightingales in 2014, which became a BBC Radio 4 documentary, winning huge admiration and becoming a Pick of the Year.

The festival programme includes guided walks to discover where nightingales are singing, including special access to locations usually not open to the public and musical nights inspired by and featuring the distinctive song of the nightingale.

The RSPB’s Adrian Thomas, who helped organise the festival, said: “The nightingale is an amazing bird, difficult to spot but has a song that is impossible to forget. It is a song that has inspired poetry throughout the ages and provided the soundtrack to many summer sunsets.

“But this wonderful song might one day be lost from our countryside, so we have created the Nightingale Festival as a way of not just celebrating their song but showing everyone just what we might lose if nightingales disappear from the UK.”

The nearest festival events are folk singer Sam Lee’s concert Singing with Nightingales at The Lantern in Bristol on May 22, and an RSPB nightingale walk at Highnam Woods, near Gloucester, May 17 and 23.

Of course you could try any local woodland or thicket, or raise your chances by following the information on the recent nightingale spotting at the Cotswold Water Park.

l For more information on the Nightingale Festival, visit rspb.org.uk/nightingalefestival. For the Wiltshire Ornithological Society and updates on nightingale sightings, visit wiltshirebirds.co.uk.