Winter visit pays for the pipers: Mud flats provide feast for lively dunlins
Seattle Times staff reporter
White-bellied, stiff-legged and distinguished by its emphatic, high-pitched call of "kree!," the dunlin is the shorebird of winter in Puget Sound country.
Long-distance migrants from the high Arctic, dunlins are in fat city once they reach the rich, tide-nourished salt marshes and mud flats.
Together, the network of Puget Sound estuaries comprises a stopover of international importance on the Pacific Flyway.
Tens of thousands of overwintering shorebirds from Padilla Bay to Totten Inlet assure there is no such thing as the dead of winter along Puget Sound.
Dunlins, a type of sandpiper, are a gift that arrives with the gray, beginning their migration here in late October.
The birds typically are just 8-½ inches long. When captured they are surprisingly sweet-scented, wearing the perfume of the salt marsh, says Joseph Buchanan, a wildlife biologist with the state Department of Fish and Wildlife who has banded dunlins.
In the hand, dunlins are warm to the touch, soft and fluffy, with fast-beating hearts, Buchanan said. They weigh less than an apple.
Dunlins are site faithful, returning to their same overwintering grounds year after year. They usually live a decade but seldom as long as 15 years.
Puget Sound offers them a soft winter berth.
Totten Inlet in winter is quiet as a lullaby, bathed in silvery light and spiced with salt air. The tide rolls in and out like a whisper.
Hummocks of long, soft grass, like hairy heads, tuft the salt marsh, braided with tide-cut channels.
The dunlin's table is set as the tide retreats, revealing mud flats soft and wet as chocolate sauce, a glassy surface reflecting the white bellies of the dunlins.
Dimples in the mud are the telltale traces of worms, tiny crustaceans and other shorebird fare.
The dunlin, or Calidris alpina, is a type of sandpiper. Dunlins comprise 95 percent of the overwintering shorebird population of Puget Sound.
They can be found in flocks more than 4,000 strong in Totten Inlet, where they will remain until May.
While just 10 minutes from the state Capitol, this finger of salt water that probes into the mud flats of the south Sound is nearly pristine.
Winter shorebird counts will peak here at more than 5,000 birds, including black-bellied plovers, dunlins, greater yellowlegs and Western sandpipers.
The state Department of Natural Resources added 50 acres to the Kennedy Creek Natural Area Preserve in October with a $418,000 purchase that included Totten Inlet. In all, 116 acres are protected at the site.
Just how the dunlins navigate here from their Arctic breeding grounds is a mystery.
Their journey over thousands of miles of coastline may be guided by the stars, some scientists believe. Whatever their strategy, it appears to be hard-wired from the time they hatch.
Dunlins are among the smallest birds feeding on these busy mud flats. The black-bellied plover stands over the dunlin like a halfback, nearly twice its size. Gulls look as if they have been pumped up with an air compressor.
The plovers are strategic, visual foragers, standing back on elegant long legs to watch the mud for worm bubbles that are their dinner bell.
Not the dunlin. A so-called tactile feeder, it scrambles over the mud, probing with its bill until it finds food, then sucks it in without ever lifting its head.
With its short neck, it has a hunchbacked appearance, and it is all business as it works its black bill, long as a pinky finger and slightly curved.
Dunlins feed at the tide line and have vision keen enough to forage in the middle of the night, if they must, to catch a dropping tide.
Theirs is an urgent errand: They must pack in enough food to sustain themselves in the chill and, later in spring, to fatten up for the 2,000-mile flight back to the Arctic for breeding season.
Dunlins usually lose weight during the winter. Not at Totten Inlet. And the birds here can gain more weight come spring because the inlet is so rich in food, Buchanan said.
That doesn't make it a safe place. Shorebirds working these mud flats have to divide their attention between food and predators.
Dunlins are falcon snacks. Deadly predators that do in the dunlin with a variety of moves, falcons use stealthy, stalking flights and dive-bombing plunges to prey on a fleeing flock.
"They come through and really tear up the place," Buchanan said.
As a falcon swooped overhead at the inlet, dunlins yanked their bills from the mud and took flight as a group: Like schooling ocean fish, they find safety in numbers.
Built for fast flight and tight turns with narrow, pointed wings, dunlins can switch direction collectively in an instant.
As a flock, they can execute midflight evasive maneuvers in a dazzling, synchronized display. Scientists still don't know how they do it:
There's the ripple, in which each dunlin rotates its body slightly on its axis, just after its nearest neighbor. The effect, as one bird after another rotates, is that of a ripple passing through the flock like stadiumgoers executing The Wave.
Flying in a flock, dunlins can also alternately display their brown backs, then their white bellies, all at the same time, a snazzy maneuver called flashing.
They can fly in an upward, spiraling column like rising smoke, sometimes flashing and rippling simultaneously. The goal: avoid becoming dinner.
Buchanan first began observing dunlins at Totten Inlet 25 years ago, watching this eat-or-be-eaten ballet.
"At first, it was just a good place to watch falcons," he said. But in time, the dunlins, too, won him over.
"They breed in the Arctic, migrate over desolate coastline and overwinter in mud flats like these that are undisturbed," Buchanan said. "They are a symbol of the wilderness."
Lynda V. Mapes: 206-464-2736 or email@example.com. Natural Wonders appears every other Monday.