Bordoibam-Bilmukh Bird Sanctuary

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