There are usually not too many varieties of shore-birds along the coastlines of Thailand during most of the year. But come winter, and we will see visitors in the tens and hundreds of thousands, adding life and colour to the shores, lakes, marshes and fields of the country.
Areas where large numbers of shorebirds feed are indicators of an abundance of macrofauna, which in turn, means an abundance of marine life that ensures a constant food supply for man.
Most of these migratory birds come from northern Asia _ the Tundra plains of Siberia and the extreme north of Russia. When the winter winds start to blow, these areas will become a snow-covered landscape. Streams and other water sources will ice over, making it hard to forage for food. Instinctively, these birds will seek warmer climates in the south where food is abundant so they can survive the winter months.
As Thailand is near the bottom of the Asian continent, the shorebirds that migrate thousands of kilometres from the north of China find it a perfect spot to rest their weary wings, while the majority of migratory birds fly from Siberia, Japan and Korea, following the eastern coastline of China, through Vietnam to Thailand, before continuing to Malaysia and Indonesia, or even further on to Australia.
Another group from Japan take a different route, island hopping through the Philippines and Indonesia, with Australia as their final destination.
Every year in the cool season, we will find large flocks of shorebirds foraging for food along the mudflats, saltpans and other watering holes in Thailand.
The Asian Dowitcher in full breeding plumage.
This is most evident along the Inner Gulf of Thailand, which is a large mudflat caused by deposits from four major rivers that empty into the gulf, namely the Mae Klong River, the Tha Chin River, the Chao Phraya River and the Bangpakong River. Here, alluvial soil is gradually deposited, and when the tide is low, the river delta emerges, which is rich in minerals and organic matters, sea worms and other mud inhabitants. This is the habitat for various marine animals and invertebrates, providing a perfect diet for shorebirds.
That's why the Inner Gulf of Thailand plays such an important role in the lives of migratory birds in the region. The most frequently seen visitors are the Red-necked Stint, the Curlew Sandpiper, the Lesser Sand Plover and the Marsh Sandpiper. The area also provides an off-breeding-season refuge for rare and endangered birds such as the Spoon-billed Sandpiper, the Nordmann's Greenshank and the Asian Dowitcher.
October to November is the best time for birdwatching in this area, since this is when the main flocks arrive. During the middle of the migratory season, the birds might split up for different destinations, or have already passed through Thailand to continue their journey onwards. Another good birdwatching period is March-April when the birds stop over again enroute to their respective locales.
Feeding habits of these shorebirds depends largely on the tide. During low tide, the delta emerges, providing a large feeding ground for the entire bird community. At high tide, the birds will fly inland to rest along the saltpans, shrimp farms and other coastal water sources. Feeding is not limited to daytime only; nocturnal low tide is a perfect time for some birds, particularly long billed birds that peck into the mud to feel out their prey without the need for vision.
Several varieties of shorebirds feed together, wading through shallow water or mud, using their long bills to sift through the mud to find polychaete or sea worms, crustaceans, and insects. When their bills sense the movement of their prey under the mud, they quickly snap up this delicious meal without the need to even look at what they're eating. That's why their eyes can always been on the lookout for approaching enemies.
It is said that shorebirds can easily be seen, but not so easily recognised. If you go to a coastal area in the cool season, you will see large flocks of birds. However, they are mostly small in size, with similar colourings _ brown or dappled grey. When seen together they all look alike, and when seen against the background of the muddy delta, they practically blend in with the landscape. That's the beauty of survival in the ecosystem, that allows them to camouflage themselves to escape their enemies.
Despite the similarities of their foraging habits and their outward appearance, if you look closely you will notice there are several small distinguishing features. The size, shape and proportion of their beaks differ according to the depth of water and mud where they forage for food. That's nature's way of assigning concessions to different bird species, so there's plenty of food for everyone.
The large, long-legged birds like the Curlews use their long, curved beaks to burrow deep into the mud, much like the Gotwits. They wade through the water, burying their beaks into the mud, sometimes even holding their heads underwater. The smaller Knots have shorter beaks and therefore feed in shallower waters, dipping their beaks into the mud quickly to find food. The Stints, with their short legs and beaks, feed in very shallow water or mudflats together with the Plovers which alternately walk, run and stop to peck at food in an amusing dance sequence. The Turnstones, on the other hand, isolate themselves to the rocky beach covered with pebbles and broken coral, where they turn over the stones to find hidden delicacies.
Despite the vast expanse of delta, each bird jealously guards its feeding space particularly the Plovers. If any other bird should so much as come near its territory, a chase ensues.
Although these shorebirds are guests from faraway shores that only come and stay for a temporary period of time, as polite Thai hosts we have to make them welcome. Actually, preserving the natural environment does not just benefit the birds; the end result is the sustainable co-existence between human beings and nature. Birds are an indicator of the richness and abundance of the land. If there are large numbers of shorebirds, that means an abundance of crustaceans and fish as well as mangrove forests which provide a perfect nursery for marine life. A well preserved eco-system means survival for mankind.
When taken into the big picture, migration begins in September (some arrive as early as August), with the return trip lasting till April or May. With eight months for the migration period, they actually spend more time in the warmer climate than in their own locale.
When it's time to return to their natural breeding grounds in summer, shorebirds will congregate for a final binge to stock up on energy. This is when mature birds shed their feathers and grow a new breeding plumage, jokingly called the wedding trousseau, which is more colourful and attractive to help in their courtship process.
Most shorebirds take on a breeding plumage of cinnamon colour in various parts of the body. The Ruddy Turnstone will change from its usual dappled brown colour on its back, wings and tail feathers to a crimson hue, while the Red-necked Pharalope, which usually features a white body with a dark grey wingtip and tail, will develop a cinnamon accent around its neck. That is to say these migratory birds look their best on the return flight to nest. That's when we can view them at their best, and that's how many have received their names.
Often, when you observe shorebirds during the summer months, and see them in their red tinted breeding plumage in the hundreds of thousands, it's almost as if you're at a Wedding Fair!
When it's time for the shorebirds to get married, the weather in the northern hemisphere has become milder. Food and water sources are once again abundant, and the landscape is more receptive to the prospect of breeding and nesting.
And so the cycle of life of shorebirds continues.
Save the Spoony
Spoon-billed Sandpiper (Eurynorhynchus pygmeus)
Among the hundreds of thousands of migratory birds that make Thailand their temporary home during the winter months, there is one particular species with a peculiar looking beak like a little spoon. That's the Spoon-billed Sandpiper.
At only 15cm long, this is one of the smaller shorebirds with breeding grounds in the northeast coast of Siberia in Russia. In winter, its non-breeding season, the birds will fly down the Pacific coast, stopping for food along the Yellow Sea, before heading further down to the southeast of the continent. Sightings have been reported around the coast of China, South Korea, Japan, Myanmar, Thailand, Vietnam, Malaysia and Singapore, and as far as the south of India and Bangladesh.
The birds were first reported in Thailand in 1984 at Khao Sam Roi Yod National Park, Prachuap Khiri Khan, followed by regular sightings around the inner Gulf of Thailand.
The Inner Gulf of Thailand is arguably the most important location in Asia, or perhaps even in the world, for the conservation of Spoon-billed Sandpipers during their migratory season because it is the only place where you can regularly find at least 10-20 birds feeding here each year. There are one or two regular visitors every winter at the saltpans of Khok Kham, Samut Sakhon, while at the saltpans at Ban Pak Talay, Phetchaburi, there have been sightings of up to 16 of these birds.
Listed in the ''Very Rare'' category of birds on a global scale, the migratory Spoon-billed Sandpipers draw a large number of birdwatchers from all over the world to Thailand during the winter months, hoping to catch a glimpse of this strange-looking bird.
The Bird Conservation Society of Thailand (BCST) has a programme to conserve the inner Gulf of Thailand to protect the shorebird community, both migratory and local, with particular emphasis on the Spoon-billed Sandpiper. There is ongoing gathering of information, and the latest report from early 2011 indicates the presence of 17 of this species in the area.
Global climate change, combined with the change in land use on the Spoon-billed Sandpiper's migratory route has resulted in dwindling areas for their refuge. Furthermore, Russia's tundra _ the breeding ground of the Spoon-billed Sandpiper _ is drying up increasingly, resulting in a drop in numbers by 80% over the past 30 years. From the latest census, which puts the number at less than 400 in the world, the Spoon-billed Sandpiper is now on the International Union for Conservation of Nature's Red List of critically endangered species.
Saltpans provide an important feeding ground for shorebirds during high tide when the sea covers the mudflats.
The Curlew Sandpiper, the Red Knot and the Lesser Sand Plover are frequent visitors to the saltpans.
