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cvanbosk

All I want for Christmas ... is to understand Dunlins.

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What the heck is the deal with Dunlins? According to Cornell, their size (length) range ranges from 7.1 to 8.7 inches. That's about a 30 percent variation! A quick look through similar shorebirds shows that the normal size variation is typically much smaller. I never paid much attention to this because in my normal birding grounds on the east coast of Florida, dunlins are always smaller than sanderlings. But last weekend I made a trip over to the west coast ... and got real confused. In the photo below, notice the gargantuan bird to the right of the two sanderlings. I desperately tried to convince myself it wasn't a dunlin - but couldn't. It just seems too doggone big. Can someone please put me out of my misery?

cropDSCN4157.thumb.jpg.5c519ca8afc9764ab06caaf222b62cd8.jpg

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You're correct that the back rightmost bird is a Dunlin. However the other two birds are not Sanderlings, they are some sort of peep, possibly Western Sandpiper.

I had never noticed that size variation about Dunlins, but that is interesting. I wonder if the differences in size are related to gender, or disjunct breeding populations, or what?

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These look a bit more like Semipalmated to me.   Flatter back profile, a little darker eye stripe, not as front heavy as Westerns appear.  any phoros of the bills?

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They could well be Semipalmated, I was operating under the assumption that Semipalmateds don't winter in the US, but I don't know anything about Florida so I may be wrong. They do appear rather slender and are relatively dark, especially in the breast, which suggest Semipalmated.

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The bills seem on the long side for SESA.   and if these are recent pics then WESA seems more likely as AlexH mentions👍

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Bill shape and length looks fine for Western for those two. There should be no Semis in the US in winter.

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There are many subspecies of Dunlin, which is the main reason behind the large variation in size. Not many other arctic-breeding shorebird species are polytypic, probably due to the nature of their migrations.

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