Researchers raise red flags after discovering concerning trend among bird populations: 'A long-term decline'

Each year, the world quietly relies on an ancient system of movement to stay in balance. It happens overhead and offshore, across borders most people never think about. 

Across South Asia, that system is now under strain, as migratory birds lose the habitats they depend on to survive their winter journeys.

What's happening?

Researchers across Bangladesh, Nepal, Pakistan, India, the Maldives, Bhutan, and Sri Lanka are documenting widespread degradation of wetlands and coastal ecosystems, reported Mongabay. 

Rapid urban growth, agricultural expansion, pollution, unplanned fishing, and land conversion are shrinking or fragmenting critical stopover sites. 

For example, Bangladesh sits at the intersection of both major flyways and hosts hundreds of migratory species each year. While official estimates list about 310 species, ornithologist Sayam U. Chowdhury said the real number is likely closer to 400. Many of them are already under threat, including the spoon-billed sandpiper, Baer's pochard, and greater spotted eagle. 

"When waterbodies are drained, polluted or heavily altered, it destroys the habitats and food resources these birds depend on during their non-breeding season," ornithologist Chowdhury explained, per Mongabay.

Similar patterns are playing out across the greater region. In Pakistan, wetlands are being drained or filled, making life especially difficult for wading birds like black-tailed godwits and Eurasian curlews. In Nepal and Bhutan, overfishing has reduced prey for fish-eating birds, contributing to declines of rare species such as the white-bellied heron.

Why is wetland decline concerning for migratory birds and humans?

Migratory birds operate on tight energy margins. After flying nonstop across mountains and deserts, they rely on familiar wetlands to rebuild fat reserves for the next leg of their journey. Without them, they are in peril.

"This leads to increased mortality en route, reduced breeding success upon reaching their destinations due to poor physical condition, and a long-term decline in population viability," Zulfiqar Ali of the University of the Punjab told Mongabay. 

Birds arriving at degraded sites often cannot recover, leading to higher mortality and fewer successful breeders. 

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For people, the loss of wetlands also means weakened natural flood control, declining fisheries, and reduced resilience for communities that depend on healthy waterways. As habitats vanish, progress toward more stable, livable environments slows for everyone. 

What's being done to restore wetlands and bird populations?

In many countries, governments and communities are already protecting pockets of wetlands, forests, and coastal areas that still function as safe havens.  Both Bangladesh and India have signed on to the UN Convention on Migratory Species, committing to coordinated conservation efforts. 

But Zulfiqar noted that restoring key wetland areas through legal frameworks, establishing new protected areas, and implementing sustainable water management policies will be necessary.   

Conservation and civil society organizations across the region, such as the Bombay Natural History Society and SCOPE Foundation, are also working at the community level to restore habitats and manage fishers more sustainably. Experts have stressed that long-term success depends on cooperation across borders, since migratory birds do not recognize them.

"International cooperation along the flyway is also essential, as the birds are a shared responsibility," Zulfiqar added.

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