Subject: Basic-plumaged Dunlin/Western Sand ID (was: Re: East Bay, Oly, oops.)
Date: Jan 8 23:54:10 1998
From: Michael Price - mprice at mindlink.bc.ca


Hi Tweets,

Rob Saecker writes:

>Reading a little further in Scott's book (East Bay Bird Guide, btw), I find
>that "dunlin are far and away the most commmon shorebirds around PS during
>winter." And I have to admit that I didn't take dunlin into consideration
>when making my i.d., and with my mediocre shorebird skills, I was too busy
>trying to make sure they weren't least. Sigh. I still *think* they are
>westerns, but I sure ain't sure of it. Sorry.

What makes the ID just a bit tougher than you'd think--how do you mistake a
dark cold brown-grey Dunlin (DUNL) for a small pale Basic-plumaged Western
Sandpiper (WESA)?--is that it appears most of the WESA which winter this far
north are Basic 1 males: they seem browner than adults in Definitive Basic
(which, after Sanderling, is the palest of all the small Calidris
sandpipers), and can, in isolation, be similar to Dunlin.

Quick 'n dirty ways to separate them are 1) since mostly they're immature
males, the WESA bills are short and relatively stubby (for a WESA), nothing
like the long decurve of DUNL; 2) face is paler on the WESA, usually with a
clear supercilium, where DUNL has dark cold grey-brown head; 3) DUNL is
usually an overall cold grey-brown, head, breast, upperparts and wings,
while WESA is usually a medium brown on the upperparts; 4) WESA has a
clearer pale breast with indistinct streaking relegated to the sides where
DUNL has dark grey breast and obvious streaking; 5) together, DUNL is about
50% bulkier than WESA; 6) and, finally, WESA has webbing between the toes
here DUNL has none, usually visible at fairly close range (to ~75-100
meters) under most conditions, sometimes further.

Now some of these wintering WESA are gonna short-billed enough to get you
thinking maybe Semipalmated Sandpiper or maybe even a stint. Unless you hear
the call, or have the world's greatest expert at small-Calidris Basic
plumages standing next to you, forget it. Trust me. Many have gone down that
road, but few have returned. '-)

Michael Price A brave world, Sir,
Vancouver BC Canada full of religion, knavery and change;
mprice at mindlink.net we shall shortly see better days.
Aphra Behn (1640-1689)