Tag Archives: Seletar Dam

Is this a Greater Sand Plover?

High Ride Roost at SD

The rising tide forced this flock of Lesser Sand Plovers to roost close up to the dam. Many of them were still in their breeding plumage.

This is an often asked question when an biggish sand plover is seen. On 18th August KC Ling and Timothy Chua posted a photo of a non breeding sand plover with a longish bill taken at Seletar Dam on the Bird Sightings FB page. ID please?. As the bird in the image was a stand-alone, it received different answers from commentators. This was expected since the size of the bird in question, the length of leg and bill can all be very subjective when there are no other birds around for comparison.

GSP at SD

This is what one normally sees in the field, a lone hunched plover making identification difficult even at this distance.

But on closer study, some diagnostic features can be discerned. I was lucky to be there on the 27th August morning to photograph the same plover close up in the company of Lesser Sand Plovers (LSP), Charadrius mongolus, during a low high tide to confirm that this plover in question was a Greater Sand Plover (GSP), Charadrius leschenaultii. Let’s take a look at these photos and pick out some distinguishing features to separate these two similar-looking species.

A more hunched posture of a GSP at SD

This same plover as above, cropped for a closer look. It has a seemingly horizontal stance and a dumpy appearance – descriptions somewhat fits a Lesser Sand Plover. 

Up right posture of the GSP

The same plover again but now in a more typical upright posture. The taller stance, proportionately larger body and longer (greenish-yellow) legs now makes it easy to identify it as a Greater Sand Plover. This is an adult in the non-breeding plumage having completed a full moult at their breeding grounds before migration.  

Two LSP  showing two different color legs.

Generally LSP has darker colored legs than the GSP. But as can be seen here, the left LSP has a paler leg than the LSP on the right. The leg colour should be used as a guide  and not as the sole identification feature. Both are juveniles moulting into non breeding plumage. 

 

size comparison head on

The GSP has a visibly longer tibia (i.e. upper half of the leg), than the LSP. But in the field it is not always easy to tell as can be seen in this photo. The tibias of the GSP (background) and the LSP (foreground) looks almost the same. But overall the GSP is  clearly taller when you have the LSP nearby to compare.

Size comparison

The GSP is a few centimeters larger than the LSP and this size difference is evident in this photo with both species close to each other. But on its own and at a distance it is not that easy to tell.

 

Size does not matter.

The size difference is quite obvious in this photo as well. The GSP kept to itself and did not mix with the rest of the Lesser Sand Plovers. It would chase away any LSP that come near. But in this rare occasion, a brave LSP decided to take the fight to the bully.

Apart from the size, posture and leg length of the plovers, a useful feature to separate the two species is the size and shape of their bills. For the LSP (left below), the bill length is slightly shorter than the distance between the bill base and rear of the eye. The bill of the GSP (right below) is visibly longer in this comparison. It is also clearly more robust.

But even this feature is not 100% foolproof in garnering an identification. Some subspecies of LSP, eg. ssp. schaeferi can have bills that appear as long as some individuals of GSP, while some subspecies of GSP (e.g. ssp. columbinus) have bill shapes more similar to the LSP.

One way to tell them apart is to look out for a noticeable bulge on the upper mandible. The LSP bulge is closer to the bill tip giving it a blunt look, while the bulge of the GSP starts in the middle. The bulge near the bill tip of this particular GSP was not particularly visible and that was one reason why the ID remained tentative without the benefit of the size comparison.

Most Lesser Sand Plovers start their migration while still in their breeding plumage and only completely moult into their drabber, non-breeding plumage in their wintering grounds. Most of the early arriving GSPs to our shores have moulted into their non-breeding plumage.

Two Lesser Sand Plovers above. a juvenile on the left and an adult in breeding plumage on the right.

GPS at SD

This photo of the GSP shows the broader white wing bars on the primaries and the darker sub-terminal band on its tail. Both are minor features of the GSP.

From this case study, it is clear that it is not that easy to separate the two sand plovers by just looking at one or two features as some of the subspecies of GSP and LSP overlap in some of these features. The size of the bird, length and color of legs, size and shape of the bill, wing and tail pattern, feeding and behavior habits and plumage have to be taken together to come to a proper identification.

Text by Alan OwYong and Yong Ding Li.

All photos taken at Seletar Dam on 24th August 2016 by Alan OwYong. All photos of the Greater Sand Plover are from the same individual. 

Reference:

A Field Guide to the Waterbirds of Asia. The Wild Bird Society of Japan 1993. A Field Guide to the Birds of Thailand and South-East Asia. Craig Robson. Asia Books Co. Ltd 2000. A Naturalist’s Guide to the Birds of Singapore. Yong Ding Li, Lim Kim Chuah and Lee Tiah Khee. John Beaufoy Publishing Limited 2013. SASOL Birds of Southern Africa. Ian Sinclair. Struik Publishers. 1993. Identification, taxonomy and distribution of Greater and Lesser Sand Plovers. Erik Hirschfield, Kees Roselaar and Hadoram Shirihai. British Birds 93: 162-189, 2000.

Singapore Birding Report – September 2014

Eastern-crowned Warbler by Joesph Tan

Eastern-crowned Warbler by Joesph Tan Kok Beng.

The excitement on the last day of August went up a notch in September when the migrants were coming in thick and fast. The former Bidadari Cemetery came alive with the return of the big guns. They were lured back to their favourite stomping ground by the appearance of the Flycatchers, Shrikes and Wagtails. The Ferruginous Flycatcher landed on 21st, a new extreme date, followed by the Dark-sided Flycatcher on the 24th and the globally threatened Brown-chested Flycatcher on the 27th. All uncommon species and great ticks for the Big Yearers. Besides these, the photographers had their pick of Asian Paradise Flycatchers (5th), Yellow-rumped Flycatchers (6th), Tiger Shrikes (6th) and Forest Wagtail (13th). The bonuses were a Crow-billed Drongo on the 19th and Siberian Blue Robin on 21st. Both were first winter birds. The Drongo stayed for less than 2 days but the Robin was happy with the handouts and stayed a little longer.  Other migrants seen at Bidadari were a flock of 40 Daurian Starlings on the 13th, Asian Brown Flycatchers and the Eastern-crowned Warblers. Other migrant passerines like the Arctic Warbler was recorded at Nee Soon during the FMBC on the 14th, Brown Shrike at Tuas South on the 20th and again the Eastern-crown Warbler at Sungei Buloh on 22th

Great Knots at SD by Zacc HD

Great Knots at Seletar Dam by Zacc HD

As for the shorebirds, a total of eight Black-tailed Godwits were counted at Sungei Buloh on the 1st up from the five seen the day before. The star bid of the month were the four rare Great Knots found feeding off the Pang Sua Estuary on the 27th morning (Lau Jiasheng). Two were still there in the evening but gave the chasing Big Yearers the miss by moving over to Seletar Dam the next morning (Zacc HD). They were not seen again. Over at Mandai Mudflats, Rufous-necked Stints, Ruddy Turnstone and a lone Broad-billed Sandpiper were recorded during the Fall Migration Bird Census on 14th. The Ruddy Turnstone also turned up at Seletar Dam on 21st and at Chek Java on the 27th together with the Grey Plovers. The Greater Sand Plover that was feeding at Seletar Dam last month made a one day cameo on the 28th.

Greater Sand Plover at SD by Rey Aguila

Greater Sand Plover at Seletar Dam by Rey Aguila.

The Marsh Terns were returning to the Serangoon Reservoir this month. Both the White-winged and the Whiskered Terns were seen on the 9th while the Swift and Bridled Terns were seen flying off Punggol on the 13th. An unusual large number of Black-naped Terns (100+) were seen off Tanah Merah on the 21st. This could be the largest flock of this resident tern seen near the coast of Singapore.

The first migrant raptor was an Oriental Honey Buzzard seen over Bidadari on the 5th. Four Japanese Sparrowhawks were spotted flying through Tuas South on the 16th, the first for this Autumn. Subsequently the home owner at Blk 20 Dakota Cresent woke up to find a Japanese Sparrowhawk perched on his balcony on the 22nd. Another was reported flying over Japanese Gardens on 30th. This was where a Crested Serpent Eagle was photographed on 21st. There were reports of earlier sightings of this Eagle. Chaiyan later pointed out that this particular eagle was the burmanicus and not the malayensis race. It is larger, more rufous than black. Could most of our previous record of this eagle been this race and not the Malaysian resident?

Interesting reports of our resident species include a hard to find House Swift flying over Seletar Dam (27th) and a feeding Pacific Reef Egret there on the 15th. First record of a pair of Lesser Tree Ducks at the pond at Labrador Park and a tame Java Sparrow feeding with the Mynas at Old Airport Road Hawker Center, a recent release no doubt. Over at the Japanese Gardens, a Cinnamon Bittern was foraging at the lotus pond ( 2nd) and an uncommon non-breeding visiting  Malayan Hawk Cuckoo picked out on 24th.

Contributing Observers: Tan Boo Eng, See Toh Yew Wai, Francis Yap, Zacc HD, Lau Jaisheng, Lim Kim Keang, Lim Kim Seng, Rey Aguila, Frankie Lim, Low How Choon, David Li, Lawrence Cher, Toh Yuet Shin, Albert Low, Christina See, Lim Ser Chai, Goh Juan Hui, Geoff Lim and Alan OwYong.