By Mark Kinver
Science and environment reporter, BBC News
Colombia's gorgeted puffleg appears on the list as Critically Endangered
A record number of bird species are now listed as threatened with extinction, a global assessment has revealed.
The IUCN Red List evaluation considered 1,227, or 12%, of all known bird species to be at risk, with 192 species described as Critically Endangered.
The main threats affecting bird numbers continued to be agriculture, logging and invasive species, the report said.
However, it added that where conservation measures had been put in place, bird populations had recovered.
"It is extremely worrying that the number of Critically Endangered birds on the IUCN Red List continues to increase, despite successful conservation initiatives around the world," said Simon Stuart, chairman of the IUCN's Species Survival Commission.
The latest assessment, carried out by BirdLife International, uplisted nine species to Critically Endangered.
One species to be listed as Critically Endangered in the global survey, which began in 1988, was the gorgeted puffleg (Eriocnemis isabellae), a colourful hummingbird that was only recently described for the first time.
Conservationists say that the species only has about 1,200 hectares of habitat remaining in the cloud forests of south-west Colombia.
Yet, they add, about 8% of this area is being lost every year as a result of commercial coca plantations.
The palila (Loxioides baiilleui) is another species that has been uplisted.
This large finch has become the latest species to be categorised as Critically Endangered on Hawaii, which has become an "extinction hotspot for birds".
Conservationists hope the Mauritius fody will not end up like the dodo
"It is yet another in a long line of Hawaiian species that have suffered as a result of the introduction of invasive species," BirdLife International's global species programme officer Jez Bird told BBC News.
Some of the threats included grazing animals, which destroyed the birds' habitat, and mosquitoes that carried avian malaria.
"There are now 14 species that are considered to be Critically Endangered on the islands, a number of which could possibly be extinct, so it is depressing to see another one apparently go the same way."
The islands are isolated volcanic outcrops in the eastern Pacific Ocean, where the introduction of novel species quickly destabilises the archipelago's ecosystems.
Globally, the main threats facing bird populations continued to be agriculture, deforestation and invasive species, Mr Bird explained, adding that there was no sign of the threats disappearing in the near future.
"Invasive species are something that is very well addressed by conservation efforts, and there is scope to avoid extinctions and turning species' fortunes around," he said.
"But things like agriculture and logging are continent-wide and much bigger problems.
"To tackle these in the long-term will require policy engagements rather than action on the ground."
While the overall trend was bleak for bird species, Mr Bird said that conservation efforts were paying dividends, such as in the case of the Mauritius fody (Foudia rubra).
"It's endemic to the islands of Mauritius, where the dodo went extinct along with a number of other species.
Conservation efforts in Brazil led to a four-fold increase in Lear's macaws
"But gradually this has been turned around and we have seen a number of species in recent years being downlisted to lower categories, including this fody."
He said this was a result of work by the Mauritian Wildlife Foundation to tackle the threats posed by invasive species and habitat degradation.
The foundation had also established another population of fody on an offshore island, he added.
"Thanks to that introduction, there is now a secure population that is away from the immediate threats of invasive species, etc."
Mr Bird added that 32 species listed as Critically Endangered were the focus of conservation efforts, as part of the BirdLife International's Preventing Extinctions Programme.
Overall, this year's Red List saw 77 species change categories. While many alterations were the result of better data, 12 were the result of changes in population size or potential threats.
While nine species were uplisted to Critically Endangered, six were downlisted to Endangered.
"What the changes in this year's IUCN Red List tell us is that we can still turn things around for these species," said Dr Stuart Butchart, BirdLife's global research and indicators co-ordinator.
"There just has to be the will to act."