Monday, 30 August 2010

Peep show

Can you identify this wader, photographed on the Azores in October?
A change of pace now from practical to theory. How difficult is a Sanderling to identify? Could it be confused with a Pectoral Sandpiper? Or what about Temminck’s Stint and Baird’s Sandpiper, or even Western and White-rumped Sandpipers? These are just three of the ID issues that have – maybe surprisingly – created much debate on the ID-Frontiers list recently, with some well-known birding names on both sides of the Atlantic taking opposing sides as plumage features and photos have been analysed to resolve the identity of ‘problem’ waders.

In many real-life situations, of course, most individuals of all these species are readily identifiable, or at least usually so. Less clear-cut was the small Calidrid depicted in a photo which we published in Birdwatch (172: 37) in Peter Alfrey’s excellent ‘Eye of the Storm’ article, about birding on the Azores in autumn 2005. The middle ‘peep’ in a trio of shorebirds on Terceira, identified as White-rumped, Semipalmated and Least Sandpipers at the time, was latterly suggested by Marshall Iliff (and eventually many others) to be a Little Stint.

Nearctic peeps are far more numerous in the Azores than in Britain, to the point where Semipalmated Sandpipers are said to be outnumbered by Little Stints only by about 2:1. I have seen obvious examples of both species in the archipelago, and also less clear-cut individuals (including a wintering bird which I consulted Peter about).

So having recently revisited the ID issues surrounding small Calidrids, I was reminded of a bird (see photo above) which I myself saw in the Azores one October. Before discussing this wader further, readers are welcome to suggest an identification – it’s not a trick question, anonymous contributions are welcome (the more the merrier) and just a species name will suffice, but do please have a go and post your entry in the comments box below this post. I’ll be back again on this once a few answers are forthcoming.

11 comments:

  1. Western Sandpiper? Cheers James

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  2. It struck me how no-one has been keen to nail their colours to the mast so far! After taking a look at Peter Affrey's blog on the subject, and deciding someone has to go first, I'm going for a Semi-palmated Sandpiper...

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  3. I'd be trying to clinch this as Western Sand... but wouldn't like to say for certain based on one pic, since I've virtually zero experience of the species.

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  4. I think this is a Semipalmated Sandpiper, albeit with a rather long-looking bill ...

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  5. Baird's and White-Rumped also...

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  6. I believe this bird is a juvenile Semi-palmated Sandpiper.

    Here's my reasoning, and I would be happy to have it critiqued (constructively).

    o Molt times - All of the adults (Semi-palmated, Western, White Rumped, Baird's) should have at least started molting by October. This is also true of juvenile Western Sandpipers, a strong argument against this species. I do not see any signs that molting has started on this bird.

    o Primary tip extension - It's hard to see for sure, but looking carefully at the wingtips, it appears that the tertial feathers extend almost to the tips of the primaries, which would rule out White-rumped and Baird's. Also, the bill structure doesn't seem to fit these species.

    o Bill - It appears that this bird my have some debris or a drop of water at the tip of the bill. This could obscure details of the bill structure and make the bill appear somewhat longer that actual. However, the bill does not have as much droop as would be expected for most
    Westerns. Also, the length is on the long side, but still within range for Semi-palmated. Finally, even allowing for the debris, it appears that the bill is quite blunt (otherwise there would have to be a very rapid taper at the end to achieve a fine tip like a Western).

    o Plumage - To my eye, the feathers look fresh and relatively unworn, consistent with juvenile. Dark cheeks are good for juvi Semi-palmated and bad for juvi Western. Also there is no rufous on the upper scapulars as would be expected for juvi Western.

    Regarding Dunlin, the bill should be longer and more downcurved. Also, adult Dunlins should be fully molted well before October and juveniles (rarely seen south of breeding grounds) at least started. Juvenile Dunlins also have heavily streaked breasts and black feathering on the belly, not seen on this bird.

    I have virtually no experience with stints, but comparing to my Sibley guide, the bill appears to be too long and heavy for either stint.

    So, my 2 cent wager is on Semi-palmated Sandpiper.

    Andy

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  7. From a quick look at the peep, I would say that it was a Western. Dunlin-like shape, long, apparently tapered bill (despite the blob of mud at the tip), chestnut in the scapulars, solid ear-coverts. To me, it just looks like one.
    PPK

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  8. It's a Semiplamated Sandpiper, almost certainly a female on bill length and body structure.
    No moult to first-winter is evident and combined with the dark ear coverts and pattern of the lower scapulars fit Semi-p perfectly.

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