Dead Bird Quiz answer?

16 01 2015

I managed to harangue an answer out of Edward! Hurrah! Also, it makes me feel better when other people find a carcass as daunting to identify as I did. Looking at our Bird here, there’s not a lot to go on, but we might get farther than we expected on initial inspection.
We can see the sternum of the bird here, and it looks small, delicate, and roughly square shaped with some indents along what we would call the caudal border (caudal refers to the tail end of an animal). This looks like a shorebird’s sternum to me, and Edward agreed, referring to it as “very charadriform” (the order that includes shorebirds). Interestingly, the sternum looked almost like a mini-gull sternum to me, and when I thought about it further, it occurred to me that gulls and terns are also Charadriiformes, so no big shock there.
This bird in the DBQ is quite small, as one can see using both the ruler and index card as reference. So, we are looking for shorebird types with a dark wing. What other field marks can we make out? It looks like there’s a white band running along the upper wing, and in the photo of the underwing, it looks pretty bright white. What species have a white stripe on the upper wing with a white underwing? Edward suggests one: oystercatcher. Check out this photo below. The upper wing shows a strong white band tapering to not much more than a few white patches on the inner primaries. The underwing is a clean white. This bird is an adult, and the bird we have is browner overall, which would be consistent with a younger bird.

American Oystercatcher in Wilmington, NC. (Photo: Dick Daniels)

American Oystercatcher in Wilmington, NC. (Photo: Dick Daniels)

This does look promising. Interestingly, Pacific populations of American Oystercatchers lack those extra white patches on the primaries, with the white restricted to the secondary coverts. I think oystercatcher is a good bet for this bird, but I have some hesitation. I was doing my own SEANET walk the other day on the ice-stacked beach, and was trying to think of other things it could be, mainly as an exercise. We don’t get a lot of shorebirds, and I am not excellent at identifying them. But as I walked along, I saw a Sanderling take off just ahead of me, and saw its wing flash a white band as well. So, thought I, what other shorebirds show that pattern that we might take a brief look at for our own edification?

There are plenty of birds, like the Willet, that are known for a conspicuous white wing stripe, but that have a dark underwing. We can discount these. But that leaves us with several birds that still meet the requirements.

It’s hard to tell just what that white band looked like in life in our Dead Bird, but from what I can see, it looks somewhat more extensive and uninterrupted than the patches on an oystercatcher’s primaries. There are some birds in this size range with a white underwing and a broader white stripe extending well into the primaries. These include Sanderling, Ruddy Turnstone, Red Phalarope, and Dunlin. The size looks too big for sandpipers, though some species of them have this sort of coloration on the wing. None of these options is without precedent on SEANET beaches, and this seems a good opportunity to show these lovely photos of a Red Phalarope that Marcia Lyons found in North Carolina last February, though this bird was rather uncooperative about spreading its wings per SEANET protocol. Also, the phalarope has grayer wings than we see in our bird.

Photo: M. Lyons

Photo: M. Lyons

Photo: M. Lyons

Photo: M. Lyons

Overall, looking at all these other options, it looks like the general, somewhat dark, drab brown color of our bird is not quite right for the flashier, more rusty or spangled color of, say, a Turnstone’s wing or a young Dunlin. So, after casting about for a while, I feel pretty comfortable with the oystercatcher call. What this has mostly taught me is that, whenever I think I can tackle shorebird identification, I am probably wrong. Especially when all that’s left is a twisted up bit of mostly nothing. But thank you all for bearing with me.



2 responses

16 01 2015
Wouter van Gestel

No offence to Edward, but oystercatcher does not seem right to me for this pathetic leftover of a bird.
It seems to small to be an oystercatcher. If you compare the 15 cm bar with the one in the phalarope pictures, it seems about the same size, and an osytercatcher is bigger, about the size of a domestic pigeon.
I do agree with charadriform, the sternum shape and the long tertials are rather typical, and the because of the plain, warm-brown upperparts, whitish underwings and prominent white wingbar my guess is a small Charadrius plover. In this area it could be a Semi-palmated Plover (C. semipalmatus) or a Wilson’s Plover (C. wilsonia). It seems a bit too small for a Killdeer (C. vociferus).


18 01 2015

Hi Wouter,
You’re right! I had not seen your reply until this morning, but I realised already that the Oystercatcher diagnosis was totally wrong. I should have checked the measurements. After checking these I found that this little bugger comes about 10 cm short to be an O. Just stupid. If I had seen it in real life I never would have thought of an O. A plover of some sort would indeed be a better track to follow. I can agree with Semi-palmated, Wilson’s (or Common-Ringed, rare as it seems), indeed a bit small for Killdeer. Apologies for the confusion Sarah!

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