January is the month for our Asian Waterbird Census count of local areas, so we chose 24 Jan this year. We visited three areas – Kuala Muda sandspits at low tide for the terns, the paddyfields inland of Penaga (to kill time really, but also for egrets), and the Teluk Air Tawar-Kuala Muda IBA coastline, by boat, at high tide.
As it happened, the trip gave us some nice comparisons of similar-looking species, and I include some of them here for your delectation and delight!
We started at Kuala Muda, where we counted about 3,000 terns, most of them Common, and all of them far away!
Some of them very far away!
A dark morph Pacific Reef-Egret came closer briefly.
Going back to terns, we ended the day in the boat circumnavigating some poles which have been planted in the seabed to encourage colonies of shellfish. The poles are used by terns to roost at high tide, and they seemed to be not at all bothered by us, enabling much closer views.
Similar pair 1: Common and Whiskered Terns. Note the very different head pattern; the dense black on Common extends down the nape, whereas on Whiskered, it’s rather speckled and extends more or less straight back from the eye.
There were about 40 Great Crested Terns too.
The difference in bill colour and structure between different individuals was striking. I’m not sure how to account for this. Wells (1999) mentions that subspecies cristata is the one we get regularly, but that there is a possibility of the larger, more westerly race velox, which is larger overall and darker -backed. Perhaps the right hand bird is one such?
Similar pair 2: Great and Lesser Crested Terns. A single Lesser Crested Tern gave us a good chance to compare the two. Generally, Lesser has a more orangey bill, but this is not always obvious. The whiter forecrown seemed to be a good distinguishing feature.
If they can be seen alongside one another, the smaller size of Lesser is obvious.
Similar pair 3: Brown-headed (right) and Black-headed Gull (left). In Penang, Brown-headed is the common species – we counted 344 of them. In amongst them were three Black-headed Gulls, a relative rarity up on the north-west coast of the Peninsula.
On the deck (or in water), these can be quite tricky to separate, especially the dark-eyed non-adult Brown-headeds (as this one is). Brown-headed is bigger, bulkier and has a heavier bill, but these things can be difficult to be judge on a single bird. The primary pattern is a better clue, but this can be better seen when the birds are in flight…
The white leading edge of the upperwing extends all the way to the wingtip on Black-headed (below), whereas, on Brown-headed, the wingtips are ‘dipped in black ink’ (with the exception of 4 white ‘mirrors’ on the wingtips of adults).
It’s more or less the same on the underwing – on Black-headed, the outermost visible primary is mostly white and the rest are more or less black; while Brown-headed wingtips have the same triangular dipped-in-ink look.
They can be a little tricky at a distance though!
So to waders!
Trying to identify and count waders from a boat moving forward and up and down takes some doing, so we do a rough count, then take photos, stitch them together and then do a more detailed count at home. With over 14,000 birds it takes a lot longer to do the count afterwards than the actual survey! But it also has its rewards. See the little red square to the right of the panorama above?
That’s a Thai-flagged Bar-tailed Godwit in amongst the Asian Dowitchers, Nordmann’s Greenshanks, Great Knot, Far Eastern Curlew and other commoner stuff!
Similar pair 4: Nordmann’s (top) and Common Greenshank (bottom). There are 7 Nordmann’s Greenshanks in the nearer group in the top picture (among Asian Dowitchers, Bar-tailed Godwit, Grey and Pacific Golden Plovers and a Great Knot) and 8 Common Greenshanks (and a Common Redshank) in the lower picture. Nordmanns look whiter than any other shorebird because of the white chest (which is bulky) and pale grey upperparts. Common Greenshank looks less pale because the breast is slimmer and the upperparts are darker and browner. The difference in leg length is also a giveaway.
Nordmann’s love to keep their feet wet, and generally choose to roost right on the tideline at the edge of any mudflats still available. Common Greenshanks prefer to stay close to the mangroves, as do Common Redshanks and Marsh Sandpipers. For this reason, boat surveys are an excellent way to observe Nordmann’s Greenshanks! We counted 64 from our photographs.
Similar pair 5: Intermediate (left) and Great Egret (right). We saw many of these in the paddyfields. The size difference is mainly useful when both are available for comparison. Other features to notice are the small rounded head and relatively short bill of Intermediate, the extraordinarily long neck of Great and its long head and bill. Another key difference is in the shape of the gape, which terminates under the eye on Intermediate but extends well behind it in a characteristic acute triangle on Great.
And finally, nothing at all similar about these, but I thought I’d add them anyway! A young Grey Heron in flight and the empty shells of Golden Apple snails on the beach.