Myanmar is very rich in freshwater biodiversity. The inland water ecosystem of Myanmar is associated with four major rivers, the Ayeyarwady, Chindwin, Thanlwin and Sittaung. Freshwater and wetland biodiversity and ecosystems provide essential ecosystem services to the Myanmar people. Sadly, many freshwater species and habitats are rapidly being degraded and destroyed, due to several threats. Some species face habitat lost and dramatic population declines due to human activities. Conservation is urgently needed to protect freshwater habitats and populations of important threatened species.

The River Tern and Black-bellied Tern are two rare Tern species that occur in Ayeyarwady River and Chindwn Rivers in Myanmar. The Black-bellied Tern is smaller and slimmer than the River Tern, and has a distinctive black underside during the breeding season. The River Tern has been categorized as Near Threatened and Black-billed Tern as Endangered according to the IUCN Red List. Both species are rapidly declining in Myanmar, and the Black Bellied tern is probably Myanmar’s rarest bird. These two species are mainly found in big rivers and adjacent wetland areas. They breed on sandbars in the rivers when the water level is low between February to March. They nest directly on the ground, often in a small scrape on bare sand, and lay two to three greenish-grey eggs, which are blotched and streaked with brown. Our research has found an incubation period of 22 to 28 days and 25 to 30 days between hatching and fledging of the chicks.

In 2017, the WCS survey team recorded a new sub population of Black-bellied Tern with six individuals near Yaynanchaung, and located 12 individuals and two nests along the Ayeyarwady River. For River Tern, 101 individuals and 29 nests were recorded in both rivers.
During the 2018 survey, the River Tern population seemed to decrease due to intensive human activities on the sand bars: 24 nests were recorded at the Chindwin River. A total of 14 Black-bellied Terns, as well as eight fledging juveniles were recorded at the two breeding grounds in the Ayeyarwady River. All of these nests were protected by local people working with the WCS team.

 

Naing Lin

WCS Myanmar