One in every five species of bird in Britain has declined at such an alarming rate over recent years that it has been included on our national Red List.
The list is compiled periodically by the Royal Society for the Protection of Birds (RSPB) and the British Trust for Ornithology (BTO), among other organisations, and the total has risen at every successive revision. It is predominantly made up of species whose population or range has more than halved in the past 25 years – a substantial drop over a sufficiently generous time span to iron out short-term fluctuations.
Every bird in decline tells its own story about the environment, and a number of themes have emerged as the proportion of threatened farmland and woodland species, long-distance migrants and rare northerly breeding birds has increased.
Identifying species in trouble, understanding the causes, and turning around declines, where possible, takes time and money. But while the growing tally can give cause for gloom, that doesn't have to mean doom, as targeted conservation work helped species such as the woodlark and stone curlew to regain lost ground and come off the Red List when it was updated as part of the third national Birds of Conservation Concern report last year.
Efforts to clean up our seas by curbing waste discharges have, ironically, deprived this diving duck of sources of food and led to a decline in numbers wintering around our coast.
A smart black sea-duck which breeds inland on small lochs in northern Scotland in ever-decreasing numbers. Habitat changes, pollution and predation are believed to be among factors taking their toll.
The astonishing spectacle of males jousting on breeding display grounds has become an increasingly scarce sight. Numbers have been affected by overgrazing, land drainage, predation and collisions with deer fencing.
A heavyweight grouse found in Scottish pine forests, where males display with tails fanned in a turkey-like pose. Their range has contracted due to a deterioration of suitable habitat and predation.
Modern arable farming, which deprives this native game bird of cover, insect food and seedy stubble, has been blamed for its decline, with agri-environment schemes the key to its recovery.
This offshore visitor is assessed as "critically endangered" by the International Union for Conservation of Nature – not even the giant panda is classified at that level of threat.
One of our rarest breeding birds, numbering just a few dozen pairs, this secretive reed-bed specialist has been helped back from the brink following a major programme of wetlands work.
Persecuted to extinction by the early 20th century, our largest bird of prey, with an 8ft wingspan, has been successfully reintroduced to Scotland and now numbers more than 50 pairs.
Poisoned, shot and trapped for preying on red grouse, this handsome moorland raptor was virtually eliminated from Britain, but legal protection has helped it to regain some lost ground.
Wiped out in England as agricultural intensification destroyed meadows and mechanical hay-cutters mowed them down, this shy, globally threatened summer migrant is mostly confined to the Western Isles of Scotland.
This widespread farmland bird with rounded wings and wispy crest has suffered as new crop-sowing regimes and the loss of mixed farms reduced suitable nesting and foraging habitats.
A passing visitor and rare breeder in Britain, which lies at the southern edge of its range, this tiny Arctic wader's toehold in this country appears to be slipping.
Hundreds of thousands of these small brown waders gather on our frost-free estuaries to feed every winter, but numbers have slumped to their lowest levels since records began.
Wetland reclamation and hunting drove this bird from Britain by the mid-1800s and today, only a few nest here – breeding males displaying with their bizarre "ruffs" of neck feathers.
This tall wader with an elegant neck and long, straight bill is a scarce breeder, nesting in protected areas of wet meadowland and more commonly seen on estuaries in winter.
Similar-looking to the larger and more common curlew with its down-curved bill, this specially protected bird, which nests in northern Scotland, Orkney and Shetland, has suffered declines in breeding numbers.
This unusual wader, which swims and swaps sexual roles – the duller-plumaged males incubate the eggs – breeds only in small numbers by shallow pools on the Northern Isles and Outer Hebrides.
The plummeting population of this sleek piratical seabird is closely tied to failing sand eel stocks, which has been blamed on warming seas.
This resourceful gull is thriving in cities and on rubbish dump leftovers, but numbers overall have fallen with the fishing industry decline.
An elegant tern with long tail streamers, this rare breeding seabird has been affected by declining sand eel stocks and hunting in wintering areas along the west coast of Africa.
Insufficient food in both over-grazed wintering areas in Africa and intensively farmed fields in Britain, coupled with hunting on migration, have caused the severe decline of this once-common summer visitor.
The cuckoo's evocative two-note song is being heard less and less across the country, its decline mirroring that of a number of long-distance migrants that spend the winter in Africa.
This mysterious nocturnal bird has benefited from the improved management of our fragmented heaths.
Intricately patterned and well camouflaged, this member of the woodpecker family became extinct as a regular breeder by the 1970s and is now seen passing through only on migration.
Lesser Spotted Woodpecker
The population of this small and elusive canopy-dweller has fallen by more than 80 per cent in the past 25 years.
An inspiration for poets and musicians with its exuberant song, the skylark has been affected by changing crop-sowing regimes and is among 10 farmland species on the Red List.
This summer visitor is one of a number of migrants believed to have suffered from habitat loss on sub-Saharan wintering grounds.
A dainty insect-eater that frequently feeds near cattle, it may be encountering problems in Africa over winter and from the loss of mixed farms and water meadows in Britain.
This close relative of the blackbird with a distinctive white chest band is turning up in fewer and fewer numbers every spring.
Hundreds of thousands of these handsome chestnut-backed thrushes flood into Britain every winter, but very few pairs nest here – and that small number is on the slide.
This widespread thrush has turned a corner after years of decline, but still remains of conservation concern.
An abundant winter visitor joining larger fieldfares in nomadic flocks foraging on fruit trees and berry bushes and in fields, this thrush's small breeding population in Scotland has dwindled.
A small, secretive bird, its population has been on a boom-and-bust cycle over recent decades.
This summer visitor, which breeds in reed beds, was driven to extinction in the UK with the draining of wetlands and, despite making a return, numbers are plunging back towards zero.
Europe's rarest migratory songbird, this globally threatened warbler, which breeds in Eastern Europe and overwinters in West Africa, stops over in small numbers at our coastal reed beds on migration.
This accomplished mimic is an increasingly rare breeder in Britain, numbering a handful of pairs every year.
A yellow-green bird of mature upland oak woods in western Britain, the wood warbler may have declined due to changes in preferred habitats either here or in African wintering areas.
This trans-Saharan migrant is returning to Britain to breed in declining numbers every spring.
This resident species, which excavates nest holes in damp woodland, has declined in number by more than 80 per cent since 1970.
A range of factors affecting the make-up of our deciduous woodland is believed to have caused the decline of this smart black-capped tit, which visits bird feeders.
Only a few pairs of this shy, blackbird-sized yellow bird with a fluting whistle nest in eastern England, and it is in danger of disappearing altogether from the UK.
Known as the "butcher bird" for its habit of storing prey impaled on thorns, this handsome migrant, once a regular breeder, made headlines this year when a pair nested on Dartmoor.
Less than half as common as 30 years ago, this gregarious species, which roosts in huge flocks, is thought to have been affected by losses of permanent pasture and mixed farms.
Surveys show this chirpy companion is the bird most often spotted in gardens, yet it has experienced worrying urban declines, with a shortage of insect food believed to be a factor.
This rural relative of the house sparrow has nosedived in number, falling from millions to tens of thousands, with agricultural intensification depriving it of year-round sources of food.
A popular cage bird in Victorian times because of its charming twittering song, the linnet has struggled to find sufficient weed seeds on lowland farms to sustain its numbers.
A close relative of the linnet's, this streaky-brown seed-eating finch has gradually retreated northwards so that nesting pairs are now mostly found in the Pennines and Scotland.
A small and active little finch with a red forehead and a fondness for birch seeds, this widespread woodland species is becoming much more thinly scattered across Britain.
Britain's largest finch, with a bill powerful enough to crack cherry stones, this elusive resident of deciduous woodland is believed to have declined to just a few thousand pairs.
This bright canary-like bird, with its repetitive "little bit of bread and no cheese" song, is widespread in Britain, but less than half as common as it was in 1970.
Similar to the yellowhammer, this species is now found only in the South-west, where conservation work has aided its recovery from a low point of 100 pairs.
Our largest bunting and among the Red List's biggest fallers in terms of population, this rather nondescript farmland bird with a jangling song now numbers around 10,000 pairs.
The Red List totalled 36 in 1996, 40 in 2002 and the current list of 52 was published in 2009 as part of the report Birds of Conservation Concern 3 by a partnership of organisations including the RSPB, BTO and Wildfowl & Wetlands Trust.
'While Flocks Last' by Charlie Elder is published by Corgi (£7.99). To order a copy (free P&P), call Independent Books Direct on 08430 600 030, or visit www.independentbooksdirect.co.uk.