Nightingale homes have been cleared away, thickets tided up or grubbed out, and Britain's biggest single population of nightingales at Lodge Hill in Kent, is even under threat from housing development.
We have all heard of the 'canary in the coalmine' and Rachel Carson's Silent Spring. But in the case of the British nightingale, we have both rolled into one.
It is the signature voice of spring and yet it is falling silent, vanishing from one copse, thicket and wood after another, year on year.
Because so few people have now heard a real live nightingale - something everyone should experience at least once - I have been running a campaign to try and get the BBC to re-start its former annual May live broadcast of the bird. So far with no effect - but you can help by signing here.
I've also set up a website, Nightingale Nights, where you can hear the bird, hear a remarkable singer (Ziazan) who sang to one and it sang back, and find places to hear them and events to join, as well as a Soundcloud site of nightingale songs (birds and humans).
The Ecologist is based in Oxford - which for a piece about the nightingale, is a shame, as they have all but disappeared not just from the city, but from the whole county of Oxfordshire, as they have over so much of England and even from their former corners of Wales.
In his book The Nightingale and Its Song and Other Familiar Songbirds, written in 1932, naturalist and film-maker Oliver Pike described the nightingale as "common in suitable places" in Oxfordshire and stated: "I have seen more nightingales close to the city of Oxford than in any other part of England."
That could not be said now. Indeed there are probably more environmental film-makers than nightingales around Oxford today.
Fewer nightingales than people called 'Nightingale'
In 1980 a survey by the British Trust for Ornithology (BTO) found 79 singing Nightingales in Oxfordshire: another survey in 1999 found just 17. The BTO believes that if nothing is done to change current trends, the Nightingale could be extinct in Britain within 20 or 30 years.
They calculate that it has already lost 43% of its former range, and has declined over 90% since the late 1960s. The latest estimate is that there are around 5,850 singing (only the males sing) nightingales in Britain, which is fewer than people named 'Nightingale' (around 10,000).
Nightingales have always been found mostly in the south of Britain but old studies (and perhaps the distribution of people named Nightingale) show they used to be found as far north as Cheshire, South Yorkshire and Derbyshire.
They were also quite common across much of the Marches, parts of Wales, the Midlands and into Somerset, Dorset and Gloucestershire, as well as the Home Counties and East Anglia. Now they are increasingly confined to SE England - and getting rarer even there.
The decline continues. In recent years, researchers at the magnificent Ancient Woodland of Bradfield Woods in Suffolk, uncovered one factor in the disappearance of nightingales: deer are literally eating their key habitat, low dense growth such as that created by coppicing. But by the time their studies were published in full, the birds themselves had gone.
Over the past two or three decades, Southern England has seen a massive explosion in the numbers of deer, especially the small introduced muntjac which escaped from Whipsnade Zoo. They are literally eating nightingales 'out of house and home', as well as eliminating many wildflowers such as orchids, primroses and bluebells.
Lynx could help. Also, we could stop blitzing their habitat
That's one undoubted cause, and the only solution is to shoot or otherwise control muntjac and roe deer, and for landowners and managers to fence their woods, which is expensive. There are proposals to re-introduce lynx into England which could help but they'd have to get very busy. Until then, eat wild venison to help nightingales in Britain.
With a warming climate you might expect nightingales to be spreading north as some other birds are but the reverse is true. They are retreating south.
One reason maybe that in common with some other summer migrant visitors to Britain that winter in the African 'humid forest zone' near the equator (such as spotted flycatcher and turtle dove), the nightingale is not getting a 'climate signal' that spring is coming earlier in the Northern Hemisphere.
So these birds, unlike those wintering in North Africa, may still turn up at the ancestral time, only to find that key food items have gone. They could be 'out of synch'. Their wintering places too are changing, with forest converted to intensive farmland.
Other possibilities are that pesticides such as neonicotinoids may play a role, or even that hitherto uninvestigated factors such as the parallel decline of the southern wood ant, which old nightingale catchers and keepers used to use as bait and food, might be involved. But that's me speculating.
What is certain, is that nightingale homes have been cleared away, thickets tided up or grubbed out, and coppicing of woodland is far less widespread than it once was. Britain's biggest single population of nightingales at Lodge Hill in Kent, is even under threat from housing development.
It's also true that a host of insects from moths and butterflies to ants, are far rarer than they used to be. With government funded research into most of our native flora and fauna almost abandoned, we may never get to nail down all the causes until the nightingales are 'in the coffins'.
With action comes hope
There are some glimmers of hope. With help from Anglia Water, last week the BTO published a guide for landowners on how to manage 'scrub' - thickets of blackthorn and hawthorn - to maximise its suitability for nightingales.
Grafham Water near Peterborough is one place where Anglia Water has done this successfully: they deserve credit for it. If enough land mangers acted on this advice we might possibly turn the tide. The 3,500-acre re-wilding project at Knepp in West Sussex is another big success story.
Then there's the lynx, deer fencing and venison burgers, and tackling climate change, and organic farming. They'd all help.
What would it matter if the nightingales disappeared? We'd still have nightingale culture: a phalanx of poets led by Keats, endless literary references from Chaucer and Shakespeare, not to mention the Anglo Saxons (nightingale means 'night-singer' in old English), people called Nightingale, pubs called The Nightingale and a lot of Nightingale Lanes and Nightingale Closes.
Plus the BBC would have its historic recordings featuring a celebrated cellist (1924) and the painfully evocative lone nightingale singing against the drone of bombers in 1942 (Youtube video above) - the year the BBC abandoned the nightingale live broadcasts - plus David Attenborough's' tweet of the day.
Our children would still have plenty of British nightingales to listen to, only they'd all be dead. But that would leave something important forever missing from the heart of our country.
Let's not allow the nightingale to slip quietly into the night and never be heard again.
Over 2,500 people have signed so far. Please join us so we can stop this loss of experience, and focus the attention needed to rescue this magical, extraordinary creature.
Chris Rose lives in North Norfolk and is a campaigns and communications consultant and former campaigner for WWF, Greenpeace and Friends of the Earth.
Also on The Ecologist: 'Moonlit melody - the resurgent nightingales of Knepp' by Hazel Sillver.