Almost 30 percent of the UK's bird species including greenfinches and swifts are facing serious threat to survival due to factors including climate change, a report published Wednesday warned.
The "red" list of 70 birds considered most endangered was put together by a coalition of organisations the Royal Society for the Protection of Birds (RSPB) based on the observations of volunteers.
The last such report was published in 2015.
RSPB chief executive Beccy Speight said the report "is more evidence that the UK's wildlife is in freefall", and warned: "This really is the last chance saloon to halt and reverse the destruction of nature."
The number of bird species whose populations are in severe decline has almost doubled since the list was first compiled 25 years ago and has grown by three species since the last report.
The red list already contained once common birds such as house sparrows and starlings and contains 11 new species this time, including greenfinches, swifts and housemartins.
The criteria for inclusion include population decline and a reduction in the geographic area where the birds breed.
The latest fall in numbers concerns a broad range of birds with different habitats and feeding preferences, with the report citing pressures including urbanisation, changes to farmland management and invasive species.
This includes insect-eating birds that arrive in the UK in summer months and migrate to sub-Saharan Africa for winter, such as swifts and housemartins.
The report suggested possible factors including a loss of swifts' traditional nesting sites in wooden eaves of old buildings, as well as climate change and droughts in Africa.
Greenfinches, which often live in woods and farmland, went straight from the green to the red list after being hit by a parasite-induced disease.
Waterbirds that spend the winter in the UK such as Bewick's swan also joined the red list, with pressures including shifting of wintering grounds northeast due to milder temperatures.
There were also several examples of recovering populations due to conservation efforts, with the white-tailed eagle moving from red to amber after the previously extinct birds were successful reintroduced into Scotland.
But the report warned that the UK red list is now so long that conservation groups may have to be more selective in targeting which birds to prioritise, "unless nature conservation action becomes bolder, takes place over a greater scale and is much better resourced".
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)