Figure 29. This rather dull and poorly marked ‘White-faced’ Plover, perhaps a first-summer male, was photographed at Penang on 5th February 2007. It shows the characteristic wing pattern including the broad wing bar that is particularly conspicuous across the inner primaries, the white trailing edge to the secondaries, and the white tips to the median coverts, which extends as a white ‘spur’ to the outer edge of the wing. David Bakewell

Legs

Kentish Plover	Invariably dark, similar to that shown by birds in non-breeding plumage.
‘White-faced’ Plover	Legs of some males darken to pale lead-grey, but remain slightly paler than shown by Kentish. Legs of females remain pinkish or flesh-coloured.

Bill shape and colour

In both ‘White-faced’ and Kentish Plovers, the bill shape and colour remains unchanged throughout the year. 

Behavioural features and characters

During low tide at the Penang site, the mixed flock would feed on the tideline, on or near an isolated sandbar in the middle of extensive mudflats. On occasion, ‘White-faced’ Plovers were seen to hunt prey (crabs?) in a manner typical of Greater Sand Plover; head lowered, dashing across the sand to seize the prey before it could retreat into its burrow. Kentish Plovers were not seen to feed in this manner, but may also do so. Typically, when feeding, the posture of Kentish Plover was rather horizontal, with the head held hunched into the ‘shoulders’. In contrast, ‘White-faced’ Plovers would often adopt a slightly more upright stance, with more of the neck visible. This had the effect of making ‘White-faced’ Plovers appear large-headed.

When roosting, the birds would congregate in a loose mixed flock, with ‘White-faced’ Plovers always preferring the sandier, drier areas. The birds would roost both on the foreshore and on the wasteland at the edge of the construction site. Typically, however, ‘White-faced’ Plovers tended to roost by lying on the sand, legs folded beneath and head held low. Often they would choose an area of larger stones that would conceal them wholly or in part. Kentish Plovers also roosted in this manner, but were as likely to roost standing up. When disturbed at the roost, ‘White-faced’ Plovers were more nervous and tended to run fast away from the disturbance, whereas Kentish would adopt a peculiar robotic mincing gait, but not retreat rapidly with ‘White-faced’ Plovers.

The way forward

It is recognised that Kentish Plover is an extremely variable species, even within its Asian range where four or five races are described, depending on the taxonomy followed. Other races inhabiting North and South America may represent a different species – Snowy Plover C. nivosus. In addition, other populations of Kentish Plover, such as the distinctive small and pale birds breeding in the Persian Gulf, are still treated as synonymous with the nominate form.

Understandably, therefore, we are adopting a cautious approach towards the identity of these birds. But regardless of their ultimate identity, it is astonishing that these distinctive plovers have not been observed, commented upon or documented previously – although Wells (1999) did mention a bird with white lores at the Kapar Power Station roost in March 1993 (see above). What makes these events even more remarkable is that these birds have been overlooked for so long in Malaysia and Singapore; probably the two countries in the region with the longest history and strongest tradition of bird-related research, extending back almost two centuries to the founding of Singapore.

These observations establish beyond reasonable doubt that a ‘mystery’ plover does occur along the west coast of the Malay Peninsula south to Singapore between October and March. That it has only been noticed during the northern winter months, occurs with flocks of Kentish Plovers and, like Kentish Plover, appears to undertake a pre-breeding moult between January and March, suggests a northern origin.

In order to establish exactly what these plovers are, it will be necessary to compare the biometrics and DNA of these birds with that of known taxa to establish the phylogenetic relationship with other Charadrius. The best results will come from blood, feathers or fresh tissue taken from live birds, but can also be achieved using old tissue, typically toepad material, taken from old specimens held in reference collections. This work is currently in progress (Kennerley & Bakewell in prep), and details will be published in the near future.

By bringing these birds to the attention of a wider audience, it is hoped that further sightings will follow. We would be grateful for details of any other observations of these birds for inclusion in the above paper, which can be sent to either of the addresses below. All contributions will be fully acknowledged.

Acknowledgments

Our thanks go to Geoff Carey, John Howes, James Kennerley, Angus Lamont, Paul Leader, Phil Round, Brian Small, Subaraj Rajathurai and David Wells for their input on the text and comments on the photographs. Richard Chandler and Pete Morris/Birdquest generously provided the images of Malaysian and Javan Plovers which accompany this article. Chris Rose kindly supplied an image of a bird he painted at Kapar Power Station in 1993.

We are grateful to Mark Adams, Robert Pryˆs-Jones and Katrina Cook at the NHM, Tring, for allowing access to the specimen reference collection; to Wang Luan Keng and Kelvin K. P. Lim at the Raffles Museum of Biodiversity Research, Department of Biological Sciences, Faculty of Science, National University of Singapore for the loan of specimens; and to Brian Schmidt at the Smithsonian Institution, Division of Birds, Washington DC, USA, who kindly provided photographs of the type specimen of C. a. nihonensis.

Dr Tamas Szekely, Reader in Evolutionary Biology, Dept of Biology and Biochemistry, University of Bath, recommended methods by which we could work towards establishing the molecular phylogeny of these birds.

In Malaysia, Assistant Professor Shahrul Anuar bin Mohd Sah, School of Biological Sciences, Universiti Sains Malaysia, M. A. Muin, Unisains, Universiti Sains Malaysia, and Hasnan Yusop, Director, Department of Wildlife and National Parks, Pulau Pinang, supervised attempts to trap the birds in Penang.

References

Chandler, R., & Shirihai, H. 1995. Kentish Plovers with complete breast-bands. Brit. Birds 88: 136–140

Clements, J. F. 2007. The Clements Checklist of the Birds of the World. 6th edition. Christopher Helm, London.

Deignan, H. G. 1941. Remarks on the Kentish Plovers of the extreme Orient, with separation of a new subspecies. Journal of the Washington Academy of Sciences 31(3): 105–107.

Dickinson, E. C. 2003. The Howard and Moore complete checklist of the birds of the world. 3rd edition. Christopher Helm, London.

Hayman, P., Marchant, J., & Prater, T. 1986. Shorebirds: an identification guide to the waders of the world. Croom Helm, Beckenham, England

Inskipp, T., Lindsey, N., & Duckworth, W. 1996. An Annotated Checklist of the Birds of the Oriental Region. Oriental Bird Club, Sandy.

Kennerley, P. R., & Bakewell, D. N. (in prep). A systematic review of the Kentish Plover Charadrius alexandrinus complex in southeast Asia.

Leader, P. J. 2001. Kentish Plovers with a complete breast-band. Brit. Birds 94: 246–247.

Vaurie, C. 1965. The Birds of the Palearctic Fauna, a systematic reference: Non-Passeriformes. H. F. & G. Witherby, London.

Wells, D. R. 1999. The Birds of the Thai-Malay Peninsula. Vol. 1. Non-passerines. Academic Press, London.

David N. Bakewell c/o Whimbrel Cottage, Wilby, Eye, Suffolk, England IP21 5LE

Email (digdeep1962 AT yahoo.com)

Peter R. Kennerley 16 Coppice Close, Melton, Suffolk, England IP12 1RX

Email (peterkennerley AT onetel.net)

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