Close to extinction: the status of Critically Endangered species

No fewer than 10,443 species of animal, plant and fungi found on Earth are so close to the brink of extinction that they are classified as Critically Endangered on the IUCN Red List. Of those, 223 are birds. If we are to save them, we must understand where these species live, the threats facing them and what can be done to help them recover.

We play a crucial role as the designated global Red List Authority for birds. This means we evaluate every species of bird in terms of where it is found in the world, its population size and trends, ecology and crucially, threats. These metrics enable us to classify each species’ extinction risk, and show that 223 species qualify for the highest Red List category – Critically Endangered.

But this new study, published in the journal Nature Reviews Biodiversity, takes things a step further by digging deep into the data for every single species given this perilous status. As the animals, plants and fungi closest to extinction, tracking these species’ statuses tells us if we are solving the climate and biodiversity crisis and making progress towards the goals of the Kunming–Montreal Global Biodiversity Framework.

Header image: Great Indian Bustard has been classified as Critically Endangered since 2011 on account of its population having declined to fewer than 300 individuals.
© Radheshyam Bishnoi/Shutterstock

What do we know about Critically Endangered species?

Most Critically Endangered species are plants (60%), with 25% being vertebrates, 15% invertebrates and a small proportion being fungi (0.4%). In total, 97% are endemic to a single country – including 163 birds. That means that just 16 countries hold more than half the world’s Critically Endangered species, with concentrations in the Caribbean islands, the Mediterranean and Adriatic Seas, Southeast Asia, Cameroon, Madagascar, South America’s Atlantic Rainforest and Africa’s Lake Victoria.

Worryingly, 14% of Critically Endangered species are classified as being ‘Possibly Extinct’ or ‘Possibly Extinct in the Wild’. These labels indicate that we may already be too late to save these species, at least in their natural habitat. Some remain in captive populations, such as Vietnam Pheasant, and can potentially be reintroduced to the wild.

There are potentially even more species that may have disappeared, given that 344 Critically Endangered species have been identified as ‘Lost’, meaning that no records exist from the past 10 years. We work with Re:wild and one of our national Partners in the USA, American Bird Conservancy, to run the Search for Lost Birds project, which seeks to find avian species that haven’t been recorded for a decade or more. Recent successes through this project include the rediscovery of Sira Barbet and Peruvian Solitaire in southeastern Peru, Mussau Triller in Papua New Guinea and Yellow-crested Helmetshrike in the eastern Democratic Republic of Congo.

Key threats to all Critically Endangered species are agriculture, invasive alien species and logging, while hunting and trapping also affect birds in this category. Demonstrating the devastating effect non-native organisms can have on ecosystems, invasive alien species are the fourth-most prevalent threat for plants, second-most for vertebrates and most prevalent for invertebrates. Among them, mammals such as house rats, domestic goats, feral pigs and cats are the most important. The effect invasives have on birds includes direct mortality though predation and disease and indirect factors such as degradation of habitat.

More than half the world’s Critically Endangered species need the protection of crucial sites, particularly Key Biodiversity Areas (KBAs). In total, 765 KBAs qualify as Alliance for Zero Extinction sites, because they host the last remaining population of up to 1,022 Critically Endangered species – this includes 125 sites identified for bird populations. However, on average, just 42% of each of these sites is covered by protected areas or other effective area-based conservation measures.

What can we do to help Critically Endangered species?

Two-fifths of Critically Endangered species require targeted species-based interventions, such as captive breeding/propagation and conservation translocations. Our work implementing these actions has produced incredible results bringing species back from the brink and continues to do so. From Hooded Grebes in Argentina to African Penguins in South Africa and Fatu Hiva Monarchs in French Polynesia, the BirdLife Partnership is championing the conservation of Critically Endangered species and implementing key actions to save them from extinction. But we know that greater ambition from politicians and policy makers, along with substantial financial investments, are needed to resource the actions required to save and recover Critically Endangered species.

“Saving the most threatened species from extinction requires a detailed understanding of why each one is so close to disappearing. BirdLife has an impressive track record of diagnosing the drivers of declines, identifying appropriate actions, and implementing them to deliver spectacular recoveries. Scaling up this work is essential to pass on our natural heritage to future generations.”

Dr Stuart Butchart, Chief Scientist at BirdLife International 

Action through insight drives our conservation work around the world. Improving our knowledge on the most threatened species gives us the best chance to keep these perilously positioned animals, plants and fungi with us in a balanced ecosystem.

‘The status, threats and conservation of Critically Endangered species’ was produced in collaboration with Texas A&M University, the Zoological Society of London, Re:wild, South African National Biodiversity Institute and IUCN, and is published in Nature Reviews Biodiversity. DOI: https://doi.org/10.1038/s44358-025-00059-4