Global Bird Extinctions Set to Top 500 by 2100
Even the most ambitious threat reduction strategies will not prevent the loss of over 500 bird species and a major collapse in avian ecological functions
Mass extinction on the horizon
Up to 517 bird species are projected to go extinct within the next 100 years, according to a landmark global study that warns conservation efforts must change course. Published in Nature Ecology & Evolution, the research highlights that even the best-case scenario of global threat abatement would still fail to save nearly half of these species - and much of the ecological function birds provide could be lost along with them.
Drawing on trait-based modelling across 9,873 bird species, the study revealed that current conservation plans are insufficient to protect avian biodiversity and ecosystem resilience. Without more targeted recovery programmes, global bird diversity faces not just species loss but a profound reduction in functional diversity - the variety of traits that determine how birds interact with ecosystems.
“Our findings suggest that business-as-usual approaches to conservation will result in the extinction of more bird species in the next century than have been lost since 1500,” the authors warn. “The time to prioritise functionally unique species is now.”
Why extinction isn’t equal
The projected losses go far beyond numbers. The extinction of 517 bird species would reduce global avian functional diversity by over 3% - disproportionately affecting large-bodied species, specialist foragers, and those with unique ecological roles. These are the species that pollinate flowers, control pests, disperse seeds, and maintain complex food webs.
Even full-scale threat abatement - removing all current and future drivers of extinction across entire species ranges - would only reduce this to 254 extinctions. Some species are so vulnerable due to past declines, limited ranges, or evolutionary isolation that they remain at risk despite threat removal.
Without interventions aimed specifically at the most irreplaceable birds, conservation goals will continue to fall short of protecting the diversity that sustains ecosystem function.
Functionally Unique Birds at Risk of Extinction
The study highlights several functionally unique bird species that are both highly threatened and at risk of extinction within the next century. These species are examples of those occupying the most unique positions in global avian trait space – meaning if they vanish, their ecological roles are unlikely to be filled by others.
- California Condor (Gymnogyps californianus)
An enormous scavenger from North America, it is one of the most functionally distinct birds alive. Although recovery efforts have brought it back from the brink, it remains critically endangered. - Kakapo (Strigops habroptilus)
A flightless, nocturnal parrot endemic to New Zealand, with highly unique traits. It is ecologically irreplaceable and remains critically endangered despite intensive conservation efforts. - Philippine Eagle (Pithecophaga jefferyi)
A large, apex forest raptor with an extremely restricted range. It plays a crucial ecological role and is functionally unlike any other raptor species. - Andean Condor (Vultur gryphus)
Another vital scavenger species, found in South America, which contributes to ecosystem hygiene and nutrient cycling. It is near-threatened and declining. - Sulu Hornbill (Anthracoceros montani)
A critically endangered frugivore from the Philippines, playing a key role in seed dispersal in tropical forests. - Stresemann’s Bristlefront (Merulaxis stresemanni)
A Brazilian endemic known for its distinctive ecology and highly restricted distribution. It is critically endangered and considered one of the world’s rarest birds.
The case for targeted recovery
The study shows that prioritising the 100 most functionally unique threatened species could prevent over two-thirds of the projected loss in avian functional diversity. These include species like the Sulu Hornbill, Stresemann’s Bristlefront and the Andean Condor - birds with few or no ecological equivalents.
In practical terms, that means species recovery programmes must become a central plank of conservation strategy. Measures such as habitat restoration, ex-situ breeding, and intensive management could deliver enormous benefits for functional resilience, even if applied to a relatively small number of species.
Previous efforts suggest this is achievable: conservation actions since 1993 are estimated to have saved 21–32 bird species from extinction. Preventing 37 extinctions - the number needed to secure the functional roles of the top 100 species - is within reach if priorities shift.
A new direction for policy
The authors argue that global conservation targets need urgent revision. Metrics like the STAR (Species Threat Abatement and Restoration) framework assume that halting threats is enough to downlist species - but this study finds many will still disappear without further action.
Furthermore, different drivers of extinction affect different kinds of birds. Habitat loss and degradation contribute the most to overall species loss, but halting hunting, disturbance, or invasive species has a greater benefit for preserving unique traits.
To conserve the richness of avian life - not just in species counts but in ecological contributions - conservation strategies must integrate both broad-scale threat reduction and narrowly focused recovery efforts.
June 2025
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