In 1914 passenger pigeon went extinct following the death of Martha in Cincinnati Zoo, over 100 years later more than 500 bird species are facing risk of extinction, finds research study

In 1914, the passenger pigeon, once one of the most abundant bird species on earth, went extinct as the last known example, named Martha, died in captivity at the Cincinnati Zoo. In 2025, a research study warned that more than 500 bird species are likely to be wiped out from the face of the Earth in the next 100 years, due to climate change and habitat loss.

Researchers from the University of Reading in the UK noted that the number is three times higher than all bird extinctions recorded since 1500 CE.

Extinction of Passenger Pigeon


In the early 19th century, the passenger pigeon was so abundant across North America that enormous flocks could darken the sky for hours. Scientists estimate that billions of these birds once inhabited the continent, with the species potentially accounting for 25 per cent to 40 per cent of the total bird population in the United States. Yet within a few decades, this seemingly limitless population collapsed. On September 1, 1914, the tragedy reached its final chapter when Martha, the last known passenger pigeon, died at the Cincinnati Zoo. Her death became one of the most haunting examples of human-driven extinction.

The passenger pigeon, scientifically known as Ectopistes migratorius, had evolved around an extraordinary social lifestyle. The birds traveled and nested in enormous colonies, relying on vast forests for food, shelter and breeding. Their spectacular numbers once seemed to offer protection: even if predators captured some birds, millions remained. But the same behavior that helped the species survive natural threats eventually made it extremely vulnerable to humans. When massive flocks gathered, commercial hunters could kill huge numbers at once, turning abundance into a dangerous weakness.

Martha became the symbol of that disappearance. Named after Martha Washington, she lived at the Cincinnati Zoo and was believed to be about 29 years old when she died. On the afternoon of September 1, 1914, keepers discovered her lifeless in her enclosure. Her remains were immediately preserved and eventually sent to the Smithsonian Institution, where she became a permanent scientific specimen. Today, Martha represents not merely the end of a species but the consequences of assuming that nature's abundance is endless.

Extinction of Over 500 Bird Species

The study, published in the journal Nature Ecology and Evolution in 2025, reveals that the bare-necked umbrellabird, the helmeted hornbill, and the yellow-bellied sunbird-asity are the most vulnerable. The extinction of these birds would greatly reduce the variety of bird shapes and sizes worldwide, harming ecosystems that depend on unique birds like these for vital functions.

Importantly, the scientists found that even with complete protection from human-caused threats like habitat loss, hunting, and climate change, about 250 bird species could still die out.

"Many birds are already so threatened that reducing human impacts alone won't save them. These species need special recovery programmes, like breeding projects and habitat restoration, to survive," said lead author Kerry Stewart, from the University of Reading. "We face a bird extinction crisis unprecedented in modern times. We need immediate action to reduce human threats across habitats and target rescue programmes for the most unique and endangered species," Stewart added.

The researchers examined nearly 10,000 bird species using data from the International Union for Conservation of Nature (IUCN) Red List. They predicted extinction risk based on the threats each species faces. The study found that large-bodied birds are more vulnerable to hunting and climate change, while birds with broad wings suffer more from habitat loss.

Further, the team also detailed the conservation actions to preserve both the number of bird species and their ecological functions. Beyond stopping the threats, the team called for complementary conservation measures, such as breeding programmes and habitat restoration to help as many as 250-350 species survive the next century.

"Prioritising conservation programmes for just 100 of the most unusual, threatened birds could save 68 per cent of the variety in bird shapes and sizes. This approach could help to keep ecosystems healthy,” said Professor Manuela Gonzalez-Suarez, senior author of the study at the University of Reading.

Stopping the destruction of habitats would save most birds overall. However, reducing hunting and preventing accidental deaths would save birds with more unusual features, which are especially important for ecosystem health, the team said.