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Sandpipers on an arduous migration now have a rest stop all their own

  • The Rainforest Trust and the Bird Conservation Society of Thailand recently purchased 8 hectares (20 acres) of shoreland in the Gulf of Thailand to protect a vital stopover site for spoon-billed sandpipers (Calidris pygmaea).
  • Spoon-billed sandpipers fly annually from Russia to parts of Southeast Asia and depend on sites like the salty coastal wetland of Pak Thale for survival.
  • The species is critically endangered, with only about 240 to 456 adults globally.
  • This stretch of shoreland along the Inner Gulf of Thailand is also an important migrating and wintering site for other waterbirds passing through Thailand.

For the critically endangered spoon-billed sandpiper, a tiny shorebird that makes an 8,000-kilometer (5,000-mile) migration each year, wetlands are vital stopover points. To boost the small bird’s population, the Rainforest Trust and the Bird Conservation Society of Thailand (BCST) have purchased a stopover haven in the Gulf of Thailand from two banks for the species’ winter migration.

“The purchased land is currently an active salt pan which has supported a wintering population of spoon-billed sandpipers regularly every winter,” said Angela Yang, chief conservation officer of the Rainforest Trust.

Spoon-billed sandpipers (Calidris pygmaea) have plummeted in number in recent decades. It’s estimated there are fewer than 200 pairs of these birds left in the world, and around 240 to 456 mature individuals, according to the IUCN Red List.

Breeding in Russia and wintering in Southeast Asia, the spoon-billed sandpiper makes a perilous migration each year along the East Asian-Australasian Flyway, a flight path used by millions of migratory waders and shorebirds. One of its wintering grounds lies in the salty coastal wetland of Pak Thale, in the Inner Gulf of Thailand.

Pak Thale, in the Inner Gulf of Thailand, sees many species of migratory as well as local bird species throughout the year. Image by BCST.

Recognizing the Inner Gulf’s importance for migratory birds like the spoon-billed sandpiper, the Rainforest Trust and the BCST bought 8 hectares (20 acres) of shoreline in Pak Thale in September 2019. The East Asian-Australasian Flyway Partnership has long designated Pak Thale as a “Flyway Network Site,” while BirdLife International deems it an “Important Bird and Biodiversity Area.”

“Salt pans and salt ponds provide an ideal feeding and roosting spot for these birds,” Yang said. “Without such habitat, the birds can only feed on mudflats at low tide and must find a high-tide roosting spot. With salt pans, they can feed and roost both during low and high tides and the purchased land lies in the core wintering area of Spoon-billed Sandpipers in Thailand.”

Conservationists hope to manage the area exclusively for shorebirds, Sayam U. Chowdhury, assistant coordinator of the International Spoon-billed Sandpiper Task Force, told Mongabay. This will allow the birds to use the area as undisturbed foraging and roosting sites.

The spoon-billed sandpiper prefers mixed sandy tidal mudflats with an uneven surface and very shallow water. Image by Sayam U. Chowdhury.

“Without Pak Thale, these highly threatened shorebirds may not find alternative areas to feed and roost at the Inner Gulf of Thailand,” Chowdhury said.

The spoon-billed sandpiper is known to be picky about its habitat. The bird favors very shallow waters and uneven surfaces in mixed sandy tidal mudflats, found in the outermost parts of river deltas; it also prefers higher sand content with a thin mud layer on top, according to the IUCN. Residential developments, ports, fishing and aquaculture have imperiled the survival of these birds.

“The loss of stopover sites during their long-distance migration (~15,000 miles, or ~24,000 km, round trip) is one of the main reasons for population decline,” Yang said in an email.

The Rainforest Trust and BCST purchased the land from two banks on Sept. 6 last year, concluding a process that took nearly a year to finalize. The Rainforest Trust provided the bulk of the approximately $225,000 purchase price, and worked with the BCST to secure the remainder through crowdfunding both in Thailand and internationally.

A spoon-billed sandpiper, center, forages among plovers at Pak Thale. Image by BCST.

No local communities live on the purchased land, Yang told Mongabay. There are salt farmers, though, who use the land for salt production. They will be affected by the purchase as the BCST will have to maintain water levels in the salt pans for the birds rather than let them dry out. But managers are hoping to find a compromise.

“The local community has long helped protect the birds by salt farming which provides a crucial habitat for spoon-billed sandpiper and other shorebirds,” said Ayuwat Jearwattanakanok, the BCST’s public relations manager. “Local salt farmers will be able to use water from the purchased land to continue producing salt in the nearby stretches and maintain the overall shorebirds habitat at Pak Thale.”

The salt farming process they follow involves transferring the water from a water storage pond to two stages of evaporation ponds to a crystallizing pond.

“Shorebirds can mainly feed in the water storage and first evaporation pond where salinity is not too high,” Yang said. “Our plot can serve the same function as these first two ponds in the salt farming system and salt farmers can bring water from our plot into their second evaporation pond and so on. Additionally, with the existing bird tourism and potential development of eco-tourism, there are opportunities for employment.”

The BCST has also been educating and raising awareness about the importance of this habitat among local communities. The group is also working closely with Thailand’s Department of Marine and Coastal Resources (DMCR) in managing an adjacent site.

Currently, the Inner Gulf of Thailand only supports a population of around 10 spoon-billed sandpipers every winter. The number may seem low, but it still represents 2% of the total global population. Yang said the bird’s global population is falling rapidly: studies show an 88% decrease since 2002, with the population shrinking by 26% every year.

Besides the sandpipers, Pak Thale is a suitable home for other threatened waterbirds, including the great knot (Calidris tenuirostris), the spotted greenshank (Tringa guttifer),the Far Eastern curlew (Numenius madagascariensis), and the Chinese egret (Egretta eulophotes), according to Chowdhury.

Researchers have recorded both flagged and unflagged sandpipers visiting Pak Thale. Image by Sayam U. Chowdhury.

Conservation groups regularly monitor Pak Thale’s birds, with birders visiting the site almost daily during the winter months of November to February to observe and record. “We receive records of spoon-billed sandpipers and other shorebirds regularly,” Yang said.

The BCST also has a staff member at the site to carry out monthly surveys to record the numbers of all species of shorebirds visiting the purchased land and surrounding areas. The team has to date recorded at least six sandpipers visiting the purchased land, including three birds they identified from the colored bands, or flags, attached to their legs, and three unflagged birds.

“One of our satellite tagged spoon-billed sandpipers … spent a few days at Pak Thale before it migrated to its main wintering grounds in Bangladesh,” Chowdhury said. “So, the site is important for both wintering and migrating spoon-billed sandpipers.”



Zöckler, C., Syroechkovskiy, E. E., & Atkinson, P. W. (2010). Rapid and continued population decline in the Spoon-billed Sandpiper Eurynorhynchus pygmeus indicates imminent extinction unless conservation action is taken. Bird Conservation International20(2), 95-111. doi:10.1017/s0959270910000316

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