PACIFIC NORTHWEST TURTLES

There are two native freshwater turtles in the Pacific Northwest. One is very common, the other quite uncommon. The common one is the Painted Turtle (Chrysemys picta), found all over the interior of the region south to northern Oregon and locally in western Washington and the Willamette Valley. Painted Turtles are seen in great numbers basking on logs and rocks in warm lakes in the summer, but they are shy and quickly slide into the water when approached.

These turtles are all omnivores, with a wide diet including water plants, insects, crayfish, fish, tadpoles, and dead animals. In some species, mating takes place in the fall, but the sperms don't approach the eggs until spring. This is called delayed fertilization and is common in temperate-zone reptiles. The females then come ashore in summer and dig a hole in the sand in which to lay their clutches of round, white eggs. The eggs may overwinter or hatch in fall, in that case the young turtles usually overwintering in the nest and emerging the following spring.

The other native freshwater turtle is the Western Pond Turtle (Actinemys marmorata). This species, once widespread in western Washington and Oregon, has disappeared from much of its range north of the Columbia River. Considered a species of special concern, much conservation effort has been expended on it. Biologists hatch turtle eggs in captivity, then release the young when they are large enough to be less vulnerable to predation. This very successful program has been going on for two decades at Seattle's Woodland Park Zoo and has resulted in a present population of around 1500 turtles in the wild in Washington.

The most frequently observed turtle in much of western Washington is not one of these natives but is the introduced Red-eared Slider (Trachemys scripta). This species, the most common turtle in the pet trade, has been introduced all over the world. People keep the cute babies for a while, then tire of them and toss them in the nearest lake. This may be humane treatment, but it's not good for the environment, as these invasive turtles compete with native turtles and transmit diseases to them.

Two other species have turned up in Lake Washington and elsewhere, the Snapping Turtle (Chelydra serpentina) and Spiny Softshell (Apalone spinifera). These very distinctive turtles also are native to eastern North America. Both get quite large, and they live a long time and keep on growing, so there are probably a few monsters out there. They are also aggressive species that will bite fiercely, so caution is advised!

Any account of Pacific Northwest turtles should mention the marine turtles that show up in our waters. Leatherback Turtles (Dermochelys coriacea) are regular off the Washington coast. Although sea turtles are basically tropical, this is the species that ventures into colder water than the others. When seen from a pelagic birding trip, Leatherbacks usually show up as a blob in the water, only the head visible. At closer range the big ridges down the shell can often be seen. Other sea turtles, including Green (Chelonia mydas), Loggerhead (Caretta caretta) and Pacific Ridley (Lepidochelys olivacea) are much rarer, but a few have been found washed up on northwest beaches.

Dennis Paulson

SHOREBIRDS ON THE MOVE

Every spring, about the beginning of April, flocks of shorebirds begin their annual migration up the Pacific coast on their way to Alaska and other points north. Sandpipers and plovers by the tens of thousands use the coastline as a pathway to their summer homes, feeding on the abundant populations of marine invertebrates and depositing fat to fuel their long-distance flights to their breeding grounds. Some birds leave the Washington coast and fly directly across the Gulf of Alaska to southern Alaska, where they stop at estuaries such as the Copper River Delta.

The most common species are Western Sandpipers, Dunlins, and Short-billed Dowitchers, in that order. At the same beaches, mudflats, and tidal pools are smaller but still substantial numbers of Black-bellied and Semipalmated Plovers, Greater Yellowlegs, Whimbrels, Marbled Godwits, Ruddy Turnstones, Red Knots, Sanderlings, Least Sandpipers, and Long-billed Dowitchers. At the same time, Black Turnstones, Surfbirds, and Wandering Tattlers feed along rocky shores as they move north, and Red-necked and Red Phalarope flocks settle on the ocean offshore.

These birds take advantage of a spring flush of invertebrate growth and recruitment, and they find no lack of goodies to help them put on weight. Amphipod crustaceans, polychaete worms, and small bivalves are among the most abundant fauna in birds that feed on and in sand and mud. These animals are so abundant that just about all the shorebird species using the area feed on them. Barnacles, mussels, and snails are staples of the rock shorebirds, and planktonic crustaceans fill the bellies of phalaropes.

Shorebird migration peaks on the Washington coast in the last week of April and first week of May, when the maximum number of species and individuals are present. Grays Harbor and Willapa Bay and the beaches adjacent to them always support the largest numbers, and the abundance of these birds provides a stirring spectacle every spring. Concentrations of some species in Grays Harbor are the highest south of Alaska.

And there is a Grays Harbor Shorebird Festival every spring to enjoy these concentrations: http://www.shorebirdfestival.com/.

Unfortunately, shorebird numbers have been declining, so the spectacle gets a little less spectacular every year. More importantly, we don’t have a good handle on the cause of the decline. Presumably it relates to loss of habitat on either the wintering grounds or at migration stopovers, as the arctic and subarctic breeding habitats are still relatively intact.

It’s also possible that anthropogenic changes are reducing the abundance of shorebird prey, another factor that we don’t know much about on a grand scale. There are still lots of shorebirds, so we have some time to work out an effective conservation plan, and there is such a plan for the U.S. (http://www.fws.gov/shorebirdplan/).

Dennis Paulson