On 18th October 2008, photographers had a field day at the Sungei Buloh Wetland Reserve when a Eurasian Curlew (Numenius arquata) was spotted among a flock of Whimbrels (Numenius phaeopus) by Robert Teo, among others. This is an uncommon non-breeding winter visitor and passage migrant that begins to arrive as early as 24th August till 22nd March.
This curlew is one of the largest of the waders and has an exceptionally long and decurved bill. According to Gils & Wiersma (1996), a curved bill results in a great reduction in the size of the tongue. So the bird has to remove prey from the substrate before swallowing it. The prey is transported to the mouth by “head-jerking and a coordinated opening and shutting of the mandibles”.
On the other hand, a long, straight bill of the snipe and woodcock with an open bill cavity and long tongue enables the bird to transport prey inside the bill while it is still inserted in the substrate.
Generally, “shorebirds species that predominantly forage by probing in small holes and crevices have the most curved bills, whereas species that probe in the firmest substrate will have relatively straight bills.”
It is interesting to know that different people observe different things when encountering birds in the field. In this case, most birdwatchers simply saw a Eurasian Curlew among the other waders. But Ben Lee was impressed by the larger size of the curlew as compared to the Whimbrel (Numenius phaeopus).
Then we have Jacqueline Lau who commented: “One observation of interest was that it had a tendency to act rather aggressively towards the Whimbrels (it’ll snap at them if they came near), but tolerated the greenshanks even when the smaller waders had it surrounded in close proximity. ”
Image by Jacqueline Lau.
Gils, van J. & P. Wiersma, 1996. Family Scolopacidae (Sandpipers, Snipes and Phalaropes. In del Hoyo, J., A. Elliott & J. Sargatal (eds.), Handbook of the birds of the world. Vol. 3. Hoatzin to Auks. Lynx Editions, Barcelona. Pp. 444-533.