Unfortunately, the bird (in partial breeding plumage) was seen on the 5th January at the Tuross Lake Estuary in southern NSW (location map), about 350km south of Sydney, and although it may have been present since November, it has not knowingly been reported since.
Dunlins are medium-sized shorebirds, slightly smaller and shorter-legged than a Curlew Sandpiper but larger and more heavily built than a Broad-billed Sandpiper. The bill is slightly down-curved but varies in length between individuals, with the longest bills in the US subspecies. Presuming that this bird will now be moulting into winter plumage, it poses a more difficult but not insurmountable identification problem.
In adult winter plumage, Dunlins are mostly featureless and drab grey. They lack any significant patterns in the fringing of feathers on the upper wings and have a short and rather indistinct supercilium. This is in contrast to even partial breeding plumage, when adults sport black patches on the belly, which are a distinctive and unique identification character.
Dunlins are almost entirely estuarine so the main confusion species in Australia is likely to be Curlew Sandpiper. Broad-billed Sandpiper and Sanderling would also need to be ruled out.
In flight, Dunlins have a narrow white wing bar but no complete white rump (as in Curlew Sandpiper). Instead, they have a broad black line down the centre of the rump. They lack the split supercilium of a Broad-billed Sandpiper and the blackish shoulder patch of winter-plumage Sanderling. The latter also mostly occupies sandy beaches. There is a small chance of confusion with North American vagrant species, including White-rumped Sandpiper (which also has a white rump, like Curlew Sandpiper) and Baird's Sandpiper. The latter are shorter and finer-billed, very short-legged, tend to have broader pale fringes to the feathers and an indistinct wing bar.
On the whole, Dunlin is only likely to be confused with Curlew Sandpiper. Nevertheless, like any shorebird or suspected rarity, very careful observation is likely to be necessary to identify to species - so good scope views and copious notes!
No images or video are currently available of this species but there are some images available through Wikimedia commons that may be of help here (click on an image to enlarge):
Top right: partial plumage
Top right: almost winter plumage
Bottom left: winter plumage
Bottom right: full breeding plumage
Top Left FrankDrebin | Top Right Alnus | Bottom Left FlickrLickr |
Bottom right Mdf, edited by Fir0002
