This afternoon I spied a very light-colored, small sandpiper feeding with a flock of about 40 chattering ROCK SANDPIPERS and three droopy-billed, gray-brown (dun-colored) DUNLINS.
A SANDERLING! This is an uncommon shorebird for Seward any time of year. Homer reported one for their CBC on December 17 that was also with Rock Sandpipers.
A small population of Sanderlings nests in the high arctic tundra on the North Slope near Barrow. During migration, some stage in the Copper River Delta and some migrate through the Aleutian Islands, with sporadic winter sightings such as this. According to the Alaska Species Ranking System Summary Report, this species is in decline and of concern.
The Rock Sandpipers nest in remote islands and along the coast of western Alaska. It sure is convenient for them to come here instead of me flying to the Pribilofs or Aleutian Islands!
Most Alaskan shorebirds migrate south as early as July to escape winter, yet these hardy Rock Sandpipers with their Dunlin and Sanderling pals seemed quite at home despite our variable and often severe winter weather. The Rock Sandpipers winters farther north than any other North American shorebird.
The Rock Sandpiper flock consisted of the very light gray Pribilof Rock Sandpiper (Calidris ptilocnemis ssp ptilocnemis) and two darker subspecies that may be the Aleutian Rock Sandpiper (ssp couesi), and/or the intermediate, tschukschorum. These subspecies are quite complicated, variable, and are still under review. Thanks to Luke DeCicco for his help!
The busy sandpipers worked along the high tide line, pulling out tiny tidbits to eat. I watched one Rock Sandpiper pluck a fingernail-sized, pink Macoma clam out of the cobble beach. Even though the clam was sideways, somehow the bird managed to open wide and gobble it down, shell and all, and without pause or apparent discomfort, continue to search for more.
An Alaska Department of Fish and Game publication noted that the Baltic Macoma (Macoma balthica) is an important food source for coastal birds, especially during winter and migration stopovers. It also states that the tiny clam comprises the entire diet of the Pribilof Rock Sandpiper while wintering in Cook Inlet.
Seward regularly hosts small flocks of over-wintering Rock Sandpipers, occasionally Dunlins, and rarely Sanderlings. But it’s always a thrill to watch these incredible tough guys leap-frogging along the beach and especially to hear them gaily chattering on a short winter day like today.
Seward Sporadic Bird Report Reporter