Living in the dark Taiga forests than spans Amurland, the Siberian Blue Robin could sense that the days were getting shorter and cooler, and evenings seemed to dawn a little earlier every next August day. The Taiga also seemed to be getting quieter. Just a few days ago, the familiar Arctic and Pallas’s Leaf Warblers were still out and about the larches, but they seemed to have gone quiet lately. The Siberian Bush Warbler that shared his clump was still there, bouncing from twig to twig every morning for its insect breakfasts, but the Red-flanked Bluetail that lived just a few bushes away seemed to have disappeared, and as the sounds of other warblers and robins faded away, only the trill of the occasional woodpecker or the Long-tailed tits could still be heard. As a starry night falls upon the shorter Siberian day, our Blue Robin will take flight and fly south to where the great Amur river separates the edge of the Russian taiga from the vast agricultural fields of Heilongjiang.
In no more than two weeks, he would have reached the eastern coast of China where he will stop, with some of his kind, to eat as many insects and worms he can find before heading south again. And if he survives the perils of crossing the mountain ranges of northern Vietnam and the Malay Peninsula, it wouldn’t be long before he reaches his destination in October. Here in the tropical forests of Singapore, our Siberian Blue Robin shares his little patch with a few familiar neighbours of his spring home, like the Arctic Warbler, as well as some old neighbours he’s seen from last winter, like the Short-tailed Babbler and the brightly-hued Hooded Pitta.
The East Asian-Australasian Flyway is a group of flight paths identified by biologists, and stretches from the arctic parts of Siberia, to as far south as New Zealand. Biologists came out with the concept of ‘flyways’ to describe the ‘collection of routes’ taken by different species of migratory birds from where they breed, to the places where they spend their winter. Probably the most important flyway in the world, the East Asian-Australasian Flyway is used by more different species of migratory birds than any other flyway on Earth, as well as numerous species that are in danger of extinction, most famously the Spoon-billed Sandpiper. No one has attempted to estimate how many birds use this flyway yearly, and while some biologists think that 50-100 million waterbirds may fly along this flyway every autumn, the total number which includes many of the small songbirds like our Siberian Blue Robin, remains unknown. It may be that the entire flyway is used by as many as anything from 3 to 5 billion migratory birds altogether, if we included all the little warblers, buntings, finches, pipits, flycatchers and robins that are very widespread across Siberia, Mongolia and northern China.
In autumn when most of the birds breeding across boreal and temperate parts of Asia fly south to spend their winters in the warmer tropics, many would pass undetected as they migrate at night under the guidance of the constellations. Examples include the warblers, robins, thrushes and possibly, even the pittas. While not many people has studied these migratory songbirds here in Asia, we know that they are mostly night migrants based on similar studies of related species in Europe, North America, as well as numerous accounts of birds flying into peoples’ houses at night. Not too long ago, I received an email (with photos) from a member of a public saying that a small brown bird has flown into his flat at night on the 27th storey of an apartment block here in central Singapore (Toa Payoh). The bird turned out to be one of our migratory flycatchers, after checking the photographs enclosed. Meanwhile, shorebirds, hawks and ducks mostly migrate in the day and so are among the best known of our migratory birds as it is much easier to observe them on migration. In Singapore, we have had conducted regular surveys to count the numbers of these migrants yearly in the form of the Annual Waterbird Census in January, and the Raptor Census which is usually carried out in October-November.
Singapore sits near the heart of the East Asian-Australasian Flyway and more than 100 species of migratory birds have been recorded in our forests, wetlands and parks. While many of our migratory birds, especially the hawks and shorebirds, continue to fly south to Indonesia’s islands, and for few species like sandpipers, Australia, over 50 species spend their winter here. Birdwatchers and ornithologists call them ‘winter visitors’ or ‘winter migrants’, on account of the fact that these birds will eventually spend nearly 3-4 months of their winter and spring on this tropical island. By contrast, the birds that we term as ‘passage migrants’ are so called because they merely pass Singapore, spending anything between one day to a couple of weeks here before heading south again during the months of the northern (boreal) autumn. In Singapore, the best known winter visitors are the numerous Whimbrels, Common Redshanks, Greenshanks and Lesser Sandplovers that throng the wetlands of Sungei Buloh or Sungei Khatib Bongsu every from August-September. Not many people however realise that there are in fact migratory birds everywhere in Singapore, even on busy Orchard Road. If you took a careful look at one of those Yellow Flame and Angsana trees that line parts of Orchard road in December, you might see the drab Arctic Warbler or even the Asian Brown Flycatcher, both which hail from Russia’s Taiga forests. Heading to our tropical forests in MacRitchie or Seletar, you might see a different set of migratory winter visitors, although it can be challenging to spot them in the dense foliage. While the Eastern Crowned Warblers or the Asian Paradise Flycatchers that made it here from the far-eastern Russian region of densely forested Primorye can be easy to see some November days, it can be harder to spot shyer migrants like our Siberian Blue Robin, or the Siberian Thrush. And besides migrants from Russia, our forests also draw in a few migratory birds from Korea, northern China and regions as far south as Thailand and Vietnam. For example, Blue-winged Pittas breed mostly in continental Southeast Asia, and so made relatively short journeys here to Singapore than their counterparts from further north.
As humans increasingly change the landscape in the form of infrastructural development, urbanisation to agriculture, wildlife everywhere is increasingly threatened. Some of the most endangered wildlife in the world today include Asia’s Sumatran rhinoceros, Orang Utan, tiger and panda. Migratory birds which have received far less attention from the media and NGOs, are also at risk from extinction. Some migratory shorebirds like the Slender-billed Curlew are now so rare that few have seen one for decades, and it may already be extinct in the wild. The fast changing environments of East Asia’s coastal regions, which contains the most densely populated parts of the planet, have threatened the important resting and wintering grounds of migratory waterbirds anywhere between South Korea, northeast China to Thailand and Singapore. Species like the Black-faced Spoonbill, Spoon-billed Sandpiper and the Nordmann’s Greenshank are now on the brink of extinction, with only a couple of thousand individuals left in the wild or even less. Songbirds like robins and warblers are even more poorly known. No one knows for sure where some of China’s and Japan’s rarest songbirds like the Rufous-headed Robin or the Pleske’s Grasshopper Warbler spend their winter. Here in Singapore, we are fortunate to be able to play host to the threatened Brown-chested Jungle Flycatcher that flies in every Autumn from Central/Southern China on its way south. And as climate change increasingly takes its toll on temperate and boreal environments, it is very likely that the breeding cycles of many of these migratory birds will be affected. Scientists have already found evidence that habitat or ecological changes due to warmer seasons means that some migratory birds will not arrive in their habitats on time when food is most abundant, or that certain tundra predators like Arctic foxes may become more abundant, threatening shorebirds like Spoon-billed Sandpipers at their nesting grounds.
World Migratory Bird Day is a good time for us to take stock of the threats faced by migratory birds all over the world. As more technologies to monitor migratory birds are available to scientists today than ever before, we surely have more information that can be used meaningfully to conserve them. The power of social media also means that data can be more easily gathered than before, as much as sharing the beauty of wildlife in general, and migratory birds in particular, though various platforms not possible a few years ago. As birdwatchers and citizen scientists, many of us readers can also make a difference by submitting our observations of migratory birds to local and regional conservationists, and which can then be used by scientists to understand their ecology and help in their conservation. Action is needed now, today, because without it, it may be that in a few decades from now, the Siberian Blue Robins that keeps many of us birdwatchers and nature photographers busy today, will join that list of threatened species that keeps getting longer every year.
Article written by Yong Ding Li.
Photo Credits: Yong Ding Li, Shirley Ng & Francis Yap