Some of Britain's best-loved birds are under threat - ITV News Anglia's Emily Knight reports from the Welney wetlands.
Some of Britain's most familiar birds are under threat, with species such as swifts and greenfinches joining those most at risk, experts warn.
More than a quarter of UK bird species are now on the UK's red list - which includes starlings, nightingales, house sparrows, turtle doves, grey partridges and puffins.
Bewick's swans, which migrate in winter from Arctic Russia, are among three new bird species added to the list in the latest update.
Some 70 of the UK's 245 assessed birds are now on the list - meaning they are of highest conservation concern because of severe declines, numbers well below historical levels, or the risk of global extinction.
The latest update to the UK red list for birds, carried out by a coalition of the UK's leading bird conservation organisations, is longer than ever before.
It is nearly double what it was in the first assessment in 1996, and experts say climate change is a leading factor in the decline of many species.
At the Welney Wetland Centre in Norfolk, Bewick's swans are already arriving for winter - flying from freezing Russia in search of warmer climates and food sources.
But this season, they are clearly outnumbered by Whooper swans.
Bewick's swans are smaller than the mute swan - one of the UK's most familiar birds, which is widespread in waterways and in urban areas.
They are a more timid member of the waterfowl family than their mute counterparts, and their numbers are declining as fewer make the treacherous migration to Britain every year.
Experts say the swans' long journey is increasingly threatened by overhead power lines, illegal hunting, and - when they do get here - wetlands habitat decline.
One Norfolk birdwatcher told ITV News Anglia he used to see a lot of Bewick's swans, "but now, you have to work really hard to find them”.
What species are on the red list?
The latest red list assessment looks at 245 species regularly occurring in the UK, Channel Islands and Isle of Man and categorises them as red, amber or green-listed depending on how threatened they are considered to be.
Newly red-listed species include swifts, house martins, the ptarmigan, purple sandpiper, Montagu's harrier and greenfinch, the assessment from groups including the British Trust for Ornithology, RSPB, Wildlife Trusts and National Trust warns.
Overall, the red list has grown by three species since the last assessment in 2015, with 11 more birds red-listed, but six moved to amber and two no longer assessed.
The amber list has grown by seven species while the green list - of those birds least under threat - has shrunk by nine species.
Farmland and upland birds have seen no improvement in their "worrying plight", with more red-listed in the latest assessment, while the status of long-distance migrants to Africa is continuing to decline.
Swifts have moved from the amber list to red in the face of a 58% drop in their populations since 1995 and house martins join them due to a 57% fall since 1969, joining other birds which migrate to sub-Saharan Africa such as cuckoos and nightingales.
Greenfinches have also moved from green-listed to the red list following a 62% population crash since 1993 due to a severe outbreak of the disease trichomonosis.
The experts also raised concerns over wildfowl and wader populations which spend the winter in the UK, such as Bewick's swans, the goldeneye and dunlin, which have joined the red list, with pressures including illegal hunting abroad, ingesting lead ammunition and climate change.
Leach's storm-petrel and kittiwakes are among the birds on the red list which are threatened with global extinction.
In better news, successful reintroduction projects have helped the white-tailed eagles - which became extinct in the UK as breeding birds more than a century ago - move off the red list onto the amber listing.
The song thrush, pied flycatcher and grey wagtail have been moved from red to amber, though they remain close to the threshold for the most at-risk category, as have the redwing and black redstart.
Colonisation of the UK by new birds - much of it down to human-induced climate change - has seen five new species including the great white egret, cattle egret and black-winged stilt added to the latest review.
RSPB chief executive Beccy Speight said: "As with our climate this really is the last chance saloon to halt and reverse the destruction of nature.
"We often know what action we need to take to change the situation, but we need to do much more, rapidly and at scale."
The Game and Wildlife Conservation Trust's director of research, Dr Andrew Hoodless, said: "For many red-listed species... improving breeding success in the UK is vital - we can and must make real and immediate improvements to this through better engagement with UK farmers, land managers and gamekeepers to encourage adoption of effective packages of conservation measures."
How you can help save the birdsPaul Stancliffe, of the British Trust for Ornithology told ITV News Anglia gardeners had an important role to play.
“(There are) things that we can do ourselves in our own gardens. We can garden in a more wildlife friendly manner.
"We can put berry-bearing shrubs or a nectar-rich pond in the garden, or put a pond in - that’s probably one of the best things you can do.
“Put a nest box up for swifts - swifts will take to nest boxes house martins will take to nest cobs.
“There’s things that we can do individually that can really help.”
In order to ward off diseases like trichomonosis, which is currently affecting greenfinches, conservationists say it is spread by contaminated food and drinking water.
The experts urged homeowners to clean bird feeders regularly and temporarily stop putting out food if sick birds are seen in order to slow the disease's spread.
Pochard Roseate tern
Tree sparrow Scaup
Lesser spotted woodpecker