Seward Sporadic Bird Report
It has been fascinating to
watch the flock of about 38-40 winter DUNLINS and ROCK SANDPIPERS these past
few days through the snow showers and light rain. They are ravenous, flipping
over beach wrack, probing in the silty mud and cobble, picking up amphipods and
tiny clams in their tweezer-like bills. At times, they are quite vocal,
chattering away like old friends catching up on the latest gossip. When not
feeding, they preen and take baths in the freezing water surrounded by ice
floes. Tough birds!
The DUNLINS, numbering at
least 3, have long black bills, black legs, and overall appear light brown with
a sharp line between their "bib" and their white belly. They are easy
to distinguish even without their summertime black belly.
The ROCK SANDPIPERS are more
diverse, but all are as round as a grapefruit with short yellowish legs. The
light gray rock sands are the Pribilof Island subspecies, Calidris ptilocnemis ptilocnemis, called the nominate species. Most seem to
have a yellow-orange at the base of the bill. The slightly smaller, darker
birds with much less color are the mainland birds, C. p. tschucktschorum. Thanks to Bob Gill, Project Leader of USGS Shorebird Research for the verification of these photos.
There's an interesting
article on the Winter Ecology of Rock Sandpipers at
<http://alaska.usgs.gov/science/biology/shorebirds/rosa_winter_ecology.html>
According to the article,
Rock Sandpipers are unique to the north Pacific with fewer than 100,000
individuals, and at least 4 subspecies (including one in Russia.)
The Pribilof subspecies
(Calidris p. ptilocnemis) migrates from those 3 islands a short ways to the
Alaska Peninsula, Cook Inlet (and, I should like to add, Seward.) It was
surprising to read that the presence of these hardy shorebirds wintering along
the frozen coasts was apparently first noted by scientists only within the last
10 years. I guess either no one was looking, or knew who to contact. It is an
amazing sight!
The Shorebird Guide by O'Brien, Crossley, and Karlson notes the
Pribilof subspecies is larger, distinctly more pale, and has lighter flank
streaking than the other races. The mainland subspecies (C. p. tschucktschorum)
is slightly smaller with a shorter bill, and breeds on mainland Alaska,
wintering south to California. The
Aleutian subspecies, (C. p. couesi) breeds in the Aleutian Islands and is
largely resident but may winter to Washington.
Sibley's Guide to Birds
cautions that the mainland and Aleutian populations have too much variation to
really differentiate them. And then there's the Purple Sandpiper that looks
almost identical to Aleutian and mainland subspecies, and if it reads the bird
books, knows that it should not be here.
It's all very interesting and
provides a lot to think about!
Happy Birding!
Carol Griswold
Seward Sporadic Bird Report
Reporter
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