First Record of Over-Summering Spoon-billed Sandpiper Eurynorhynchus
pygmeus in Thailand
By Krairat Eiam-Ampai, Somchai Nimnuan, Thiti Sonsa, Smith Sutibut
& Philip D. Round
This article was originally published in Stilt 60
(2011) the journal for the Australasian
Wader Studies Group and was kindly submitted by Philip
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routine monthly surveys of over-summering shorebirds and other waterbirds
conducted by the Wildlife Research Division of the Department of
National Parks, Wildlife and Plants Conservation of the Thai government,
a single Spoon-billed Sandpiper Eurynorhynchus pygmeus
was found feeding among Red-necked Stints Calidris ruficollis
on newly accreting intertidal mudflats at Khok Kham, Samut Sakhon
Province, Thailand (c. 13° 31’ N; 100° 19’ E)
on 19 July 2010. Many shorebirds display delayed maturity, not returning
to natal sites until their second or third year (Loftin 1962, Summers
et al. 1995, Rogers et al. 2006) and it has long
been assumed that first-year Spoon-billed Sandpipers do likewise
(Tomkovich 1995, Zöckler et al. 2010a). This appears
to be the first documented record of a Spoon-billed Sandpiper over-summering
in the non-breeding grounds. Given the critically endangered status
and ongoing rapid population decline of Spoon-billed Sandpipers
(Zöckler et al. 2010a, b), this over-summering record
is highly significant.
The same individual
was photographed by SS almost one month later, on 16 August 2010,
when it roosted on saltpans. Its primaries were in active moult,
with score being “555554[1 or 2] 000” and the tertials
had been dropped or were growing. A few black-centred, breeding
plumage feathers were visible in the mantle and scapulars, but the
bird was otherwise in grey, non-breeding plumage (Figures 1 and
three (unmoulted) primaries were extremely bleached, brownish and
pointed, supporting the supposition that this was a first-summer
bird. Although firstyear shorebirds frequently renew a few outer
primaries in a partial post-juvenile moult, some do not, and there
are many species in which only a proportion of the population undergoes
such a moult (Higgins & Davies 1996, Marchant & Higgins
1993, D. Rogers, in litt.). While the detailed ontogeny
of the moult of Spoon-billed Sandpiper appears to be unreported,
the extreme wear and bleaching of the outer primaries of the present
individual was thought typical among unmoulted first-summer shorebirds.
Additionally, the primary moult (more than 50% completed by mid-August)
was too advanced to indicate normal post-breeding moult of an adult
(C.D.T. Minton, in litt., D. Rogers, in litt.).
What was thought
to be the same bird was seen on 17 and 21 September when its stage
of moult had progressed to the extent that it more or less resembled
“typical” nonbreeding adults (S. Daengphayon, pers.
comm.). The latter sightings still pre-dated the arrival of non-breeding
Spoonbilled Sandpipers in the Thai Gulf, usually occurring in October
(Round & Gardner 2008).
Figure 1. Over-summering Spoon-billed Sandpiper
with wing extended, enabling determination of primary moult status.
Khok Kham, Samut Sakhon Province, Thailand, 16 August 2010 (Photo:
Figure 2. Over-summing Spoon-billed Sandpiper showing
upperparts feathering. Khok Kham, Samut Sakhon Province, Thailand,
16 August 2010 (Photo: Smith Sutibut).
Kham and nearby sites in Samut Sakhon Province constitute one of two
major clusters of sites in the Thai Inner Gulf where about 10–20
Spoon-billed Sandpipers regularly winter (Nimnuan & Daengphayon
2008, Round & Gardner 2008). The initial sighting, on newly accreting
mudflats, may be highly relevant to the habitat preference of Spoon-billed
Sandpipers which, in some parts of their non-breeding range (especially
the Meghna Delta of Bangladesh), appear to favour accreting shorelines.
(Enam ul-Haque, in litt.). The observation was made at the site of
a conservation project which is successfully reversing coastal erosion
using traditional methods (bamboo stakes) instead of intrusive concrete
sea-walls, administered by the Department of Marine and Coastal Resources,
in collaboration with the local community. Such accreting sites may
be a valuable though highly transient resource for Spoon-billed Sandpipers.
Experience in Bangladesh shows that as the substrate stabilises and
compacts, Spoon-billed Sandpipers are among the first shorebirds to
disappear, presumably moving elsewhere (Enam ul-Haque, in litt.).
In Thailand, more coastline is eroding rather than accreting, and
erosion is worsened by subsidence (caused by the unregulated extraction
of ground water), reduced sediment inflow due to dam construction
on rivers, and unzoned developments in the coastal zone. At least
130 sq km in 18 Thai coastal provinces were planted with mangroves
during 1998–2003 (Round & Gardner 2008) to offset erosion.
Since provincial and national authorities frequently choose to plant
mangrove seedlings on mudflats, overtaking the process of natural
succession, this could further deprive Spoon-billed Sandpipers and
other shorebirds of key intertidal feeding areas. Integrated management
and zoning of the both onshore and offshore habitats along the Inner
Gulf coast should be adopted so as to restrict inappropriate developments,
reduce erosion, and rehabilitate both onshore and offshore habitats.
This would safeguard both shorebirds and other biodiversity values,
and sustain the traditional (salt-farming and inshore fishing) lifestyles
of the human inhabitants.
We thank Enam ul-Haque, David Melville, Clive Minton, Danny Rogers
and Christoph Zöckler for their comments on drafts of this manuscript,
and Suchart Daengphayon for sharing details of his Spoon-billed Sandpiper
sightings. We also thank an anonymous reviewer for comments on an
earlier version of this manuscript. Philip Round is supported by The
Higgins, P.J. & S.J.J.F. Davies. (Eds.). 1996. Handbook
of Australian, New Zealand and Antarctic Birds. Volume 3. Snipe to
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of Thailand. Bird Conservation Society of Thailand Bulletin
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migration of shorebirds from Australian nonbreeding grounds'. Chapter
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Round, P.D. & D. Gardner. 2008. Birds
of the Bangkok Area. White Lotus, Bangkok.
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young waders in southern Africa delay their first return migration
to the breeding grounds? Ardea 83: 351–357.
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Spoon-billed Sandpiper Eurynorhynchus pygmeus. Russian
Journal of Ornithology 4: 77–91. (In Russian.)
Zöckler, C., E.E. Syroechkovskiy & P.W. Atkinson. 2010a.
Rapid and continued population decline in the Spoon-billed Sandpiper
Eurynorhynchus pygmeus indicates imminent extinction unless
conservation action is taken. Bird Conservation International
Zöckler, C., E.E. Syroechkovskiy, Jr. & G. Bunting. 2010b.
International Single Species Action Plan for the Conservation of the
Spoon-billed Sandpiper (Eurynorhynchus pygmeus). Technical
Report Series 23. BirdLife International Asia Division, Tokyo
and CMS Secretariat, Bonn.
Philip D. ROUND, Department of Biology, Faculty of Science,
Mahidol University, Rama 6 Road, Bangkok 10400 Email: email@example.com
Krairat EIAM-AMPAI, Wildlife Research Division, Department of National
Parks, Wildlife and Plants Conservation, Phaholyothin Road,
Chatuchak, Bangkok 10900
NIMNUAN, Wildlife Research Division, Department of National Parks,
Wildlife and Plants Conservation, Phaholyothin Road,
Chatuchak, Bangkok 10900
Wildlife Research Division, Department of National Parks, Wildlife
and Plants Conservation, Phaholyothin Road,
Chatuchak, Bangkok 10900.
Smith SUTIBUT, Bird Conservation Society of Thailand, 221, Mu 2,
Soi Ngamwongwan 2, Bangkhen, Muang District, Nonthaburi 11000.