Tuesday, October 20, 2009

it's waterfowl time

Fall is the time when thousands of waterfowl (ducks, geese, and swans) move into the Pacific Northwest from farther north and east. Vast numbers of these birds breed in Alaskan and Canadian wetlands, far enough north that these wetlands freeze each winter, and the birds move ever southward as their habitats freeze from north to south.

The first to come in are the dabbling ducks of interior marshes. Flocks of Northern Pintails, American Wigeons, Green-winged Teals, and others begin to arrive in late August. When they come, they all look like females, the males still in the eclipse plumage that camouflages them while they molt all their flight feathers on the breeding grounds. But by October many of these males are in their distinctive and showy breeding plumage, which they wear through the winter and into the next summer.

Meanwhile, large numbers of scoters have been appearing at Northwest coastal locations, where they undergo the same flight-feather molt that the dabbling ducks undertook on their breeding grounds. Many of them remain for the winter in the same areas, even north to Alaska, as marine environments are more resistant to freezing. In October, many of the diving ducks that have completed their molt in northern waters arrive. These birds feed in deeper water, and deeper water bodies freeze more slowly than shallow ones, so they can remain longer at high latitudes. This group includes scaups and Canvasbacks and their relatives, as well as many more scoters.

Migratory goose flocks, which begin to appear in late September, peak in October. They include Snow Geese from Siberia and Canada, Cackling and Greater White-fronted Geese from arctic and subarctic latitudes in Alaska and western Canada. These birds, in their V-formations and lines, are the most impressive migrants, but duck flocks, especially on the outer coast, can be impressive as well.

Finally, in November the last of the diving ducks begin to appear, including Buffleheads, goldeneyes, and mergansers. These birds stay as far north as they can as long as they can, but eventually they are driven out by the freezing of the larger lakes. By this time Trumpeter Swans from southern Alaska and Tundra Swans from farther north have appeared on our wetlands.

Many waterfowl continue their migrations beyond the Northwest, but so many of them stay here through the winter that this is close to the best, if not the best, region on the continent for ducks, geese, and swans. It’s time to go out and see for yourself.

Dennis Paulson

No comments: