Bordoibam-Bilmukh Bird Sanctuary

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About Bordoibam-Bilmukh Bird Sanctuary

Location and Size: It is situated on the boundary of Dhemaji and Lakhimpur districts in Assam and covers an area of approximately 11.25 sq. km and lies at an altitude of 90-95 meters above mean sea level.
History:
- Declared a wildlife sanctuary in 1996 by the Assam government.
- Originally part of the River Subansiri (a tributary of the Brahmaputra), which now flows 7 km away from the wetland.
Climate and Vegetation:
- Experiences a moist tropical climate with an average annual rainfall of about 2,000 mm.
- Dominated by flooded valley grasslands and wetland vegetation.
Avian Biodiversity:
- Hosts a variety of migratory waterfowl in winter.
- Home to globally threatened species such as the Spot-billed Pelican (Pelecanus philippensis) and Lesser Adjutant (Leptoptilos javanicus).

Overview:

The Bordoibam-Bilmukh Bird Sanctuary (BBBS) in Assam, once a thriving habitat for diverse avian species, has experienced a 72% decline in bird species count over the past 27 years.
This alarming biodiversity crisis has been attributed to anthropogenic pressures such as fishing, poaching, egg collection, and land-use changes.

Decline in Avian Diversity

Species Count:
- In 1997, the sanctuary recorded 167 avian species.
- Recent studies (2022-2024) revealed only 47 species, marking a 71.85% decline.
Temporal trends: The decline has been drastic since 2018, as noted in comparative surveys:
- 2011 Survey: Recorded 133 species (86 resident, 23 migratory, 24 local migrants).
- 2017-2018 Survey: Recorded 120 bird species, alongside 133 macrophytes, 68 fish species, and seven aquatic fern species.
Migratory species: Recent records include Brown Shrike, Citrine Wagtail, White Wagtail (winter migratory), and Lesser Kestrel (summer migratory).

Q1: What are wetlands?

Wetlands are transitional ecosystems between terrestrial and aquatic environments, characterized by water saturation at or near the surface. They support a unique diversity of flora and fauna. Examples include marshes, swamps, bogs, and mangroves.

News: Assam bird sanctuary records 72% decline in bird species count in 27 years – The Hindu