Guwahati: In a breakthrough for bird conservation in Assam, researchers have documented the largest-ever congregation of the endangered Black-bellied Tern (Sterna acuticauda) at Dibru-Saikhowa National Park.
On October 19, 2024, a flock of 19 individuals was spotted near the Aisung area of the park, split across a sandbar — “eleven on one side and eight on the other.”
The study, published in Zoo’s Print, underscores the importance of the sighting: “This sighting is significant for northeast India, particularly for Dibru-Saikhowa National Park, as prior records indicate only a sparse presence of this species in the region with no documentation of such a large congregation.”
The Black-bellied Tern (Sterna acuticauda Gray, 1832) is one of 23 tern species found in the Indian subcontinent. It is native to countries across South and Southeast Asia, including Bangladesh, Cambodia, India, Laos, Myanmar, Nepal, Pakistan, Thailand, and Vietnam, with recorded occurrences in parts of southern China.
Globally, the population is estimated to range between 6,700 and 17,000 mature individuals, with more than 90% of the surviving population confined to India.
Yet, the species is facing mounting threats in Assam’s fragile riverine landscapes. Researchers warn that survival is increasingly at risk from “dynamic land cover changes, including erosion and rising water levels.”
Human pressures further compound the problem. The study records that the terns were found near Dadhiya, “an area with notable human activity, including the presence of cattle and domestic dogs.” Harmful fishing practices are also a danger: “Harmful practices such as fishing using electric generators pose further risks to fish fauna and other aquatic and terrestrial wildlife.”
Even their sandbar refuges — critical for roosting and breeding — are under siege. As the authors caution: “The sandbars are used as popular picnic spots, which can jeopardize the survival of this species.”
Highlighting the discovery, Imon Abedin, PhD Scholar, Department of Zoology, Bodoland University, said: “The recent sighting of the largest congregation of this species is truly remarkable and highlights the critical importance of this region. From a conservation perspective, it is a clear reminder that we must direct our efforts toward protecting this species and its habitat.”
Prof. Hilloljyoti Singha, Department of Zoology, Bodoland University, added: “This sighting highlights the need for more research in this biodiversity-rich region. Increased scientific study will help uncover other remarkable observations, enabling more targeted and effective conservation efforts to protect this area and its unique biodiversity.”
The findings send out an urgent conservation message: Assam’s riverine ecosystems remain one of the last strongholds of the endangered Black-bellied Tern — and without immediate protection, even this refuge may be lost.
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