March harbors nest-builders, harlequins

Local birds busy with business of making time, space for young

Posted: Friday, April 02, 2010

I tend to get a bit grumpy when winter seems to be over and spring is not quite under way, and this March was no exception.

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Photo By Bob Armstrong
Photo By Bob Armstrong

Late March, however, gave me several good things.

On a walk up Salmon Creek Road with friends, an irregular tap-tapping was heard high in the trees. Then another one. Pretty soon we saw the perpetrators: two red-breasted sapsuckers flitting from tree to tree, calling occasionally. They had recently arrived from their wintering areas to the south. It was hard to tell if their interaction was territory defense or the beginning stages of pair formation. One of the birds started to inspect an old nest hole in what we jokingly call a sapsucker condominium: a tall snag with dozens of old nest holes. Only one of these nest holes could be occupied in a given year, so this old snag represents many years of sapsucker attention.

Another interesting thing happened in the Valley. One day, as I drove down Riverside Drive, I saw a raven perched on a burlap tent covering some shrubs. This bird was assiduously yanking off bits of burlap, thus shredding one end of the tent. The next day, I watched two ravens flying off with wads of burlap sticking out of both sides of their bills. This pair was clearly in the process of lining their nest. But I have to wonder if burlap is as good a nest lining as deer hair or grass. A few days later, the owners of the tented shrubs took down the somewhat tattered tent.

On a rainy morning at the end of March, I ambled out to Point Louisa to watch the tide come in. Varied thrushes were singing. A sizable, mixed-species gang of gulls floated around a little distance off the point, not diving, apparently just loafing. A small band of surf scoters cruised along the rocky shore. Some of the males were accompanied by females, and these may later fly into the Interior to nest. Unpaired scoters sometimes stay here all year.

As the tide came in, it pushed about thirty harlequin ducks off their loafing spots on shoreline rocks. The gaudy, multicolored males outnumbered the drab females about two to one. Their scientific name is Histrionicus histrionicus, from the Latin word for an actor - i.e., someone in a colorful costume. Harlequin ducks nest along mountain streams. As is typical of most ducks, males stay with their mates until the eggs are fertilized and she starts incubating; then the males depart. Although the pair separates at this time, many pairs get back together year after year, as long as they both shall live. Individual harlequins also tend to be faithful to particular streams for nesting, returning year after year to the same stream.

Female harlequins incubate their five to eight eggs for about a month, usually in a nest on the ground but sometimes in a cavity. The ducklings can swim almost immediately and are soon paddling about in the stream. Even small ones can buck a pretty strong current and go zipping upstream almost as well as their mother. One of the treats of midsummer is seeing a mama harlequin and her flotilla of young ones bouncing around in a riffle, dodging boulders and foraging for bugs.

In our coastal populations, the whole brood gradually floats down to the sea and, if they survive their predators, may stay together for several months. In salt water, they eat a wide variety of invertebrates, including worms, snails, and crabs, as well as herring and drifting salmon eggs in season. Individuals commonly use the same wintering area year after year.

Although adult individuals tend to use the same areas again and again, this need not mean that each little local population is genetically separate from all others. Young ducks disperse from their natal areas and may settle down as adults, when they are two years old, at some distance from where they were born.

• Mary F. Willson is a retired professor of ecology.

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