Bursting from quiet to controlled panic in the space of a heartbeat, a flock of western sandpipers rose from the Grays Harbor mud flats, driven from their feeding grounds by a peregrine falcon swooping in for dinner.
| When: May 6 to 8
Where: Grays Harbor National Wildlife Refuge; festival headquarters is Central Elementary School, Hoquiam. What: Celebration of shorebirds’ spring migration. Activities include guided field trips, lectures, and displays. Some events are free, others have fees; some require registration. Tip: A smart birder takes the free bus between headquarters and the 2-mile round-trip Sandpiper Trail, a wheelchair-accessible boardwalk for the best views. Contact/Schedule: 800-303-8498, ; or Grays Harbor Chamber of Commerce, 800-321-1924. Directions: Good maps are at www.shorebirdfestival.com/fest_map.html. |
In the next 10 seconds, 50 birds shot up, swirled toward the shore, veered right and then spiraled upward in a twisting formation. The falcon made a pass but only air whistled through his talons. The falcon flew away; the sandpipers decided to search out another restaurant.
Each spring, hundreds of thousands of shorebirds stop in this estuary on their way to Arctic nesting grounds; some put 15,000 miles on their odometer in one round trip.
The 1,500-acre estuary is one of four major shorebird staging areas in North America. It’s also will be home to the 10th Grays Harbor Shorebird Festival Friday to May 8 at the Grays Harbor National Wildlife Refuge, with field trips and lectures.
Keynote speaker Dennis Paulson, author of the just-published “Shorebirds of North America: The Photographic Guide,” will talk about the biology and behavior of shorebirds.
Grays Harbor is an estuary, with rivers providing fresh water and the ocean providing salt water.
“When it goes out, it exposes the mud flats, which are full of life, very small living things that birds like to eat,” said Sheila McCartan, outdoor recreation planner for the refuge.
“The shorebirds stop at places like Grays Harbor that have lots of mud flats. They spend a day, or two or three or four, storing up fat reserves.”
The exposed mud flats are the key to the migration. Tens of thousands of shorebirds can concentrate here at one time because of the vast amount of food.
The Grays Harbor National Wildlife Refuge, in the northeast corner of the harbor, is the last mud flat in the estuary to be flooded at high tide, concentrating the birds and making it easier for birders to take in the show from Sandpiper Trail.
“The best view is two hours before and after the high tide. The birds follow the water’s edge. At low tide, more mud flats are exposed and they’re spread out all over the harbor,” McCartan said.
About 85 percent of the shorebirds are western sandpipers. Dunlins, dowitchers (long- and short-billed), black-bellied plovers, and semipalmated plovers make up most of the rest, with the black-bellied plover the largest, the semipalmated the smallest of the birds, she said.
Shorebird behavior is directly related to different bill sizes and leg lengths that allow for different feeding strategies. Those with longer legs and bills can feed in deeper water; the smaller birds with tiny legs and little bills feed at the swirling edge of the outgoing wave, so there’s less competition for resources.
It also leads to less cranky behavior than feeder birds gathered at one feeder who often feel the need to drive off other birds at this single-site restaurant.
Peregrine falcons and merlins are the main predators and triggers for shorebirds’ most impressive feature, their ability to fly wingtip to wingtip in large numbers, swerving and dipping in tight formation that a Blue Angel pilot might envy.
“It’s a strategy that a lot of animals have, a way to deflect the predator by moving in a tight ball so that no individual can be picked out by the predator,” McCartan said.
“As the falcon comes in, the birds change direction or shape of the configuration. It’s an amazing phenomenon.”
The predator’s only choice is to wait for one bird to make a mistake, or not be strong enough to keep up with the flock. The raptor strikes and flies off with the shorebird.
“Peregrine falcons can come in and completely clear a mudflat. That can be discouraging for the bird-watchers but it’s a real show,” McCartan said.
Sharon Wootton is a regular contributor to The Herald. She may be reached by e-mail at songandword@rockisland.com.
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