On 17th August 2007, Ong Tun Pin sent an image of a curlew, commenting, “I have just come back from a 10 day trip to a very exotic island destination.

“Attached is a whimbrel-like wader that I hope you can guess as the name can be derived from one body feature shown in the picture (above). I know that wader is usually hard to id but this one has one famous body part that gives its name. Not found in Southeast Asia but at the edge of the oriental region.

“Would be nice if someone could tell me if this is a juvenile and whether it is in moulting. I was told that this bird becomes temporarily flightless during wing-moult. It was reluctant to fly and I was able to do some sort of wader ‘herding’ along the beach. But one still flew away after I have ‘cornered’ it at sand banks at 4 meters away. This is not the way we do wader-watching in Malaysia where often a combined effort of scoping 60x from far distance and lurking among tall grass still scares the waders away”

It was an image of a Bristle-thighed Curlew (Numenius tahitiensis), a rare bird whose breeding population is concentrated on the mountain tundra in West Alaska. It is called bristle-thighed because of the elongated feather shafts seen at the rear flanks and thighs (left). These long, shiny ‘bristles’ are usually seen only when the bird is handled. However, Tun Pin was fortunate to have captured this feature in his image, a feature he could not see through the lens. This again shows the importance of photographic images in the study of birds and bird behaviour.

The bird winters exclusively on oceanic islands, especially small Polynesian islands. And this was where Ong Tun Pin encountered the curlew, when he was on a ten-day holiday in Tahiti in August 2007.

This is a highly migratory bird, making long distance, non-stop flight of at least 4,000 km over the open ocean. The adults begin to leave their breeding grounds from early July, followed by the juveniles in early August. They meet at their staging grounds on central Yukon Delta before migrating to their winter grounds in the South Pacific islands.

The image above of the flying bird shows its chestnut rump without stripes. This is the diagnostic feature to separate it from Whimbrel (Numenius phaeopus).

In the wintering grounds, the bird moults and about 50% of the adults become flightless for about two weeks. This is the only shorebird known to have a flightless moult. This is not a problem where they winter in remote islands where there are no predators. However, when humans settle on these islands, the flightless moulting birds are at a serious handicap, especially with the introduction of domestic cats, dogs and even pigs.

The adults depart in early May while the immature birds spend all of their pre-breeding years on the wintering grounds.

References:
1. Gils, van J. & Wiersma, P. (1996). [‘Family Scolopacidae (Sandpipers, Snipes and Phalaropes]. Pp. 444-533 in del Hoyo, J., Elliott, A. & Sargatal, J. eds. Handbook of the birds of the world. Vol. 3. Hoatzin to Auks. Barcelona: Lynx Editions.
2. Kaufman, Kenn (1996). Lives of North American birds. Boston & New York: Houghton Mifflin Co.
3. Rosair, D. & Cottridge, D. (1995). Photographic guide to the waders of the world. London: Hamlyn.

On 24th February 1990, Volker Konrad encountered and photographed a plover new to Singapore at Changi. He sent his observation, including a picture, to the Singapore Records Committee set up by the Bird Group of the Nature Society (Singapore). The committee identified the bird as a Long-billed Plover (Charadrius placidus). This was reported in the Singapore Avifauna 11(4) that appeared only seven years later.

Subsequently Konrad published his finding, based on the identification provided, in the Oriental Bird Club’s scientific journal, Forktail (2005).

In the December 2006 issue of the OBC’s bulletin, BirdingASIA, Paul J. Leader, a birder based in Hongkong, successfully challenged the identification of the bird. According to Leader, the bird seen in Singapore way back in 1990 was actually a Kentish Plover (C. alexandrnius), not a Long-billed.

Konrad, the birder who sighted the bird at Changi, has so far retracted his published record and according to Birding ASIA, “…the Singapore Records Committee (Nature Society Singapore) now agrees that this record concerns the Kentish Plover.”

Well and good. A mistake has been rectified. There were no ornithologists in the Singapore Records Committee then, only experienced recreational birders. Even if there were, the best of ornithologists do sometimes make mistakes in identification.

It may therefore be a good idea if in future, to avoid mistakes as much as possible, the photographs of rarities reported are sent for their opinions to leading ornithologists overseas who have long experience of birds in Asia.

According to our bird specialist, R. Subaraj, “To put everything in perspective, regardless of the status of local records, the only confirmed Malaysian record is of one at Tanjong Rhu, Pulau Langkawi, on 19th March 1968 (Wells, 1999).

“This far south, many vagrants occur in heavily moulted, winter or juvenile plumages and this emphasises the value of exercising great caution when considering such records. One must always seek advise from those with greater experience and knowledge of such birds!”

References
Konrad, V. (2005). First record of Long-billed Plover Charadris placidus in Singapore. Forktail 21:181-182.
Leader, P.J. (2006). Comments on the purported first record of Long-billed Plover for Singapore. BirdingASIA 6: 45-47.
Wells, D.R. (1999). The birds of the Thai-Malay Peninsular. Vol. I, Non-passerines. Academic Press, London.

The series on the Breeding Ecology of the Little Terns (1-6) have been incorporated into the publication below. As such, the individual posts have now been deleted. A PDF copy is available HERE.

Breeding ecology of the little tern, Sterna albifrons Pallas, 1764 in Singapore.
J. W. K. Cheah and A. Ng (2008). Nature in Singapore 1:69-73.

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The Black-naped Tern (Sterna sumatrana) is a medium-sized white bird that is easily recognised by the black band encircling the sides and back of the crown, ending just in front of the eye. Its streamlined body, long and narrow wings and forked tail adapt it well to life on the wing. It exhibits a powerful and graceful flight These terns are essentially offshore birds, feeding on fish that they catch from the coastal shallow waters by diving from a height (above). They also feed on crustaceans and insects. Insects are taken from vegetation or water surface. They may even hawk for insects in the air when the latter emerge in large numbers. The birds nest on rocky islets, making use of shallow depressions as nests. Seldom do they line their nests with plant or other materials. Prior to copulation, there is the normal courtship ritual where the pair may indulge in elaborate aerial displays (above). The male usually feeds the female with fish, who may either swallow it immediately or keep it in her bill during the display (below). During courtship feeding other males will always be around, trying to grab the fish (below two). Once a pair has bonded this courtship feeding may intensify. The male will be working hard bringing back fish for his female the whole day. This behaviour is believed to help the female judge the quality of her mate. Should the male slack, she may dump him for another. Copulation involves the male mounting the female, which may follow a short period of courtship dance (above two). Once cloacal contact is made the male dismounts. Mating may go on many times a day prior to egg laying. Usually two eggs are laid on the bare rock (above two). Both birds help in incubation, one sitting in the nest while the other out foraging. The incubation period is 21-28 days and the chicks on hatching are semi-precocial. This means that their eyes are open and they are covered with downy feathers on hatching. Also, they can walk soon after but they still rely on the adults for food (below).
The chicks are well camouflaged in their grayish and white downs spotted with black (below). Input by YC and images by Chan Yoke Meng.

“The Black-naped Tern (Sterna sumatrana) nests in a shallow depression on the rocky surface of small outcrops. Generally, two eggs are laid and incubated by both parents. Soon after hatching, the chicks wander off from the exposed nest to seek shelter behind some boulders or whatever. With the male bird flying off to look for food, the female generally keeps a watch on the offsprings.

“The period to fledgling is slightly less than a month. All through this period and even after, a chick will continuously beg for food from its parents. Days before fledgling, it will exercise its wings, especially when a strong wind blows through (above). The parent bird would generally refrain from feeding it in an attempt to encourage it to make the first move into flight. No doubt its most anxious moment is just before it attempts at flying.

“The juvenile will spread its wings, no doubt to understand how the wind catches for lift. With aid from blasts of continuous wind, the juvenile trains for its first liftoff (above). As it experiments further, the parents would keep a close watch to check progress (below).

“Sometimes it needs a timely peck from the parent to trigger take off (above). This is done when the parent feels that the juvenile is ready.

“The magical moment arrives and the juvenile makes its first flight. And I was just as exhilarated and filled with awe as the juvenile itself. Once the juvenile fledges, the parent takes off immediately after it to keep check on its progress and possibly to orientate it on its maiden flight (above).

“The juvenile, although excited to fly, learns to use its other tail functions, like flap control and maneuvering (above). Once satisfied that the fledgling has mastered the basics of flight, the parent watches from the back, as it tries to glide around (below).

“The moment of pride for the parent as the juvenile comes in tandem to demonstrate its own proficiency, like a confirmation of flight-hood (below, left).

“Wary that the juvenile may not have what it takes, especially when a predator is near, it gives a timely peck to bring it back to the landing spot (above, right). The above occur within a short moment that generally escape notice. To be able to catch them on film is both rare and powerful - maybe a chance of a lifetime to experience. Within days after, the juvenile followed its parents on a journey to the ends of the earth (below).

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“Avian photography can be fulfilling - so as long as you keep your distance and do not cause distress to your subjects.”

Dr Jonathan Cheah Weng Kwong and Xin spent time studying these birds and documenting the various stages of this exciting event as outlined above. All images by Dr Cheah.