More than half of world’s migratory bird species are declining: Study

It is estimated that approximately 51% of migratory bird species are declining globally on all major flyways on Earth. | Photo Credit: Photo File

A new study led by Georgetown University researchers and a collaboration of ornithologists from many global organizations, including the State of India’s Birds (SoIB) partnership, has revealed that more than half of the world’s migratory bird species are in decline.

The authors of the study, published in Nature Reviews Biodiversity, estimate that approximately 51% of migratory bird species are declining globally on all major flyways on Earth.

Biodiversity crisis

While nearly 300 migratory species are already considered globally threatened, many once common and widespread birds are also experiencing significant population losses, underscoring the scale of the biodiversity crisis.

In India, the paper found that long-distance migratory birds, such as those that visit India from the Arctic, are declining faster than resident birds or shorter-distance migrants.

“The extent of the decline in migratory birds is both alarming and sobering. What we are seeing is a predictable consequence of decades of environmental degradation. But these declines are not inevitable. This review goes beyond documenting the crisis by identifying major threats, highlighting critical knowledge gaps, and providing a science-based framework for reversing the decline before more species are pushed toward extinction on Earth,” said the Peter George Institute and P’Marstown University. co-lead author of the study.

The most visible

According to the SoIB Partnership, migratory birds are among the most visible and widespread components of global biodiversity. He says they help regulate insect populations, spread seeds and pollinate plants, and support food webs across ecosystems and continents.

They are also one of the primary ways people connect with nature, with millions of bird watchers and community scientists around the world contributing their observations to global databases that have become essential for understanding bird populations and informing conservation.

“However, understanding where and why populations are declining and which of the world’s 11,000 bird species should be considered migratory remains a challenge,” it said.

Use of technology

He added that scientists are increasingly using advances in tracking technology, community science initiatives such as eBird, acoustic monitoring with artificial intelligence and population modeling to identify migration routes, understand how populations are linked across seasons and uncover the causes of decline, including habitat loss, climate change, invasive species, collisions with buildings and infrastructure, disease and pesticide use.

The study authors further argued that reversing the declines would require conservation strategies that address these threats across entire migratory life cycles and international flights, rather than in isolation.

“Previous analyzes have brought global attention to the fact that North American and European migratory birds are declining at an alarming rate. But until now, we haven’t had a good assessment of how the birds are doing on all the world’s land and sea migrations,” said Nathan W. Cooper of the Smithsonian’s National Zoo and Conservation Biology Institute and co-author of the study.

Published – 25 Jul 2026 06:01 IST