Singapore lies on the East Asian-Australasian Flyway (EAAF), a migratory route used by the greatest diversity of migratory birds on the planet. Each year, hundreds of millions of birds of more than 400 species set off from as far away as Arctic Siberia to spend the winter in the tropical climate of Southeast Asia. In Singapore, many people tend to associate migratory birds with the flocks of shorebirds that visit Sungei Buloh Wetland Reserve every year from September to April. However, there are also many other species that either pass through Singapore en route to destinations further south or choose to spend their winter here. In this instalment, we profile three migratory birds which can be very difficult to see either in their breeding range or elsewhere in Southeast Asia during the migration period.
First up, we have the avian equivalent of the seafarers who made Singapore’s ports and associated shipping lanes famous. The Swinhoe’s Storm-Petrel breeds on inaccessible islands off the coast of Korea, eastern Russia and Japan and makes the annual journey to winter in the Indian Ocean. As part of the process, these birds also utilise the Singapore Straits as the quickest means to get from the Pacific Ocean to their wintering grounds. Every year during the months of September and May, chartering a boat out into the Singapore Straits can yield hundreds of these birds moving East to West (September) and vice versa (May) as they make the arduous journey between the two oceans. Flocks of tired birds can even be seen resting on the water, against the backdrop of some of the busiest shipping lanes in the world. Interestingly, this bird is surprisingly difficult to see anywhere outside Singapore, and even serious Japanese birdwatchers have visited Singapore specifically looking for this species despite living relatively close to their breeding habitats further north.
Next, we feature a secretive visitor to our well-wooded freshwater streams and ponds during the migratory season. The Von Schrenk’s Bittern breeds in the wetlands of East Asia and winters throughout Southeast Asia as far south as Sulawesi. Unlike its cousins, who inhabit open freshwater wetlands and marshes, this species appears to favour well-wooded freshwater habitats where it is usually solitary and extremely retiring. This species is apparently not uncommon in Singapore during the passage period, evident from the multiple records of dead individuals that collide with glass buildings while on migration every year. However, seeing them in the wild is a completely different matter, as they are often well camouflaged in the streamside vegetation of our forest streams and ponds. Nevertheless, in recent years it has become apparent that some individuals spend a comparatively long time around easily accessed sites, as recent sightings of a male at Lower Peirce Boardwalk and a female at Sungei Buloh Wetland Reserve demonstrate. Both these individuals were present for at least a month, providing observers with a rare opportunity to document the ecology and foraging behaviour of this little-known species. Outside of Singapore, they appear to be only rarely encountered, with one of the few regular sites being Happy Island in China during spring migration when the species passes by on their journey to Heilongjiang or Amurland.
Lastly, we feature a handsome songbird which transits in Singapore on its way to its wintering grounds in the Indonesian islands of Sumatra and Java. The Korean or Yellow-rumped Flycatcher is a sexually dimorphic species with males sporting a particularly attractive black and yellow plumage. Females are comparatively duller but can still be identified by their distinctive yellow rump. Every year in October, large numbers spend anywhere from several days to a fortnight in Singapore refuelling before making the final leg of their journey south. During this period, it is not unusual to find some trees in our forests and parks festooned with dozens of these birds, particularly after a sustained period of bad weather. Interestingly, significantly more females than males are observed in Singapore, the reasons for which are still poorly understood. Recent banding studies show that large numbers of these birds pass through small islands in the Gulf of Thailand on their way north in spring, but the species is otherwise unobtrusive and infrequently observed. One way to locate these birds is through their characteristic chattery-trill, which we have managed to obtain recordings of (xeno-canto Link). During the short aforementioned period, however, this species is locally common in Singapore and can be encountered anywhere from urban parks to our nature reserves.
Singapore, like many countries along the EAAF, is a hotspot for migratory birds between October to April every year. Beyond the flocks of waders that captivate visitors to our coasts, more than 100 species of migratory birds occur unobtrusively in our parks and green spaces, often right under the noses of visitors. The featured species are but the tip of the iceberg, and readers are encouraged to learn more about and appreciate the epic annual journeys made by many of these species, some of which are no bigger than the palm of your hand!
Photo Gallery of the birds featured:
This article is written and edited by our guest contributor Albert Low with help from Yong Ding Li. They are both highly travelled birdwatchers from Singapore, and are among the top Asian birders, ranked by number of bird species seen in Asia. Photo Credits: Francis Yap