Hundreds of bird species could vanish in the next century

Bird species add color, movement, and sound to our world. They pollinate plants, control pests, and spread seeds. But their future is in danger.

A new study from the University of Reading warns that climate change and habitat destruction threaten global bird diversity.

The loss of unique birds like the bare-necked umbrellabird, helmeted hornbill, and yellow-bellied sunbird-asity would shrink the variety of bird forms that support ecosystems.

This projection triples all recorded bird extinctions since 1500 CE. Even with protection from hunting, habitat loss, and climate change, 250 species may still disappear. Some birds are now too fragile to survive without direct help.

“Many birds are already so threatened that reducing human impacts alone won’t save them. These species need special recovery programs, like breeding projects and habitat restoration, to survive,” explained Kerry Stewart, lead author of the study.

“We face a bird extinction crisis unprecedented in modern times. We need immediate action to reduce human threats across habitats and targeted rescue programs for the most unique and endangered species.”

Large bird species are most at risk

The researchers studied nearly 10,000 bird species using IUCN Red List data and advanced models.

The results showed that large-bodied birds are especially at risk. These birds struggle more with hunting pressure and climate stress. Birds with broad wings face severe danger from habitat destruction, especially in forests.

The study went beyond just species counts. It measured the expected loss of “functional diversity,” a term describing the variety of bird shapes, diets, and behaviors.

Under current trends, global bird functional diversity could fall by about 3.2% in the next 100 years. This drop may sound small, but it would seriously damage ecosystems.

Large, distinct species often provide unique services. Their disappearance would leave functional gaps that smaller or similar birds cannot fill.

Limits of protection alone

The researchers tested three future scenarios: complete, partial, and minimal threat abatement. In the best case, where all human threats were removed across species ranges, around 250 species would still go extinct. That is nearly half of all projected losses, even with ideal conservation.

Some birds, like the Cebu flowerpecker, remain highly vulnerable despite facing few listed threats. With fewer than 70 individuals left, they may vanish without specific recovery steps like habitat restoration or captive breeding.

The study shows that reducing threats is not enough. Many species are already too close to the brink. Past damage, small populations, and isolated habitats all contribute to ongoing risks.

Threats to rare bird species

The research evaluated six main threats: habitat loss, hunting, climate change, invasive species, disturbance, and pollution.

Habitat loss contributed the most to species decline, affecting over 1,600 species. Yet when it comes to preserving unique bird traits, other threats matter more.

Driver-specific results showed that reducing hunting or accidental deaths helped conserve rare bird features more effectively, even if fewer total species were saved. That means some threats disproportionately affect birds with uncommon traits.

Birds with long tails and short beaks, for example, benefited more from reduced hunting. Birds with broad wings responded better to protection from habitat destruction. These patterns help tailor conservation actions to bird traits most at risk.

Strategic recovery of unique species

One solution stood out: target the most unique birds for rescue. The researchers created a list of 200 functionally unique species. Protecting just the top 100 could conserve over two-thirds of global bird functional diversity.

These birds include nectar-feeders, scavengers, and seed dispersers. From the Sulu hornbill to the southern royal albatross, many are island-dwelling, wide-ranging, or limited to one location. They carry traits that help regulate temperature, shape ecosystems, and fill rare ecological roles.

Preventing the extinction of around 37 of these birds could achieve this 68% protection goal. Since past efforts have already saved 21 to 32 bird species since 1993, this new goal appears feasible with commitment.

What must be done now

Even in optimistic futures, threats cannot be erased quickly or completely. Species recovery programmes, including in-situ and ex-situ measures, are needed for the most vulnerable.

“Stopping threats is not enough,” said Professor Manuela Gonzalez-Suarez. “Prioritizing conservation programs for just 100 of the most unusual threatened birds could save 68% of the variety in bird shapes and sizes. This approach could help to keep ecosystems healthy.”

Habitat protection remains key. But to safeguard ecosystem resilience, conservationists must also think about functional diversity, not just species counts.

The coming century will test humanity’s will to preserve Earth’s avian legacy. Without sharp decisions and bold action, we risk losing many birds and the ecological balance they help maintain.

The study is published in the journal Nature Ecology & Evolution.

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