Bird Lore: Marsh Wren

Photo by LeRoy Van Hee

Photo by LeRoy Van Hee

Mighty is the mouth of the tiny Marsh Wren. Jaunty is the stance of this compact bird, when it isn’t skulking in its favored habitat–the forests of cattails, reeds, and other marsh grasses. The singing male of spring doesn’t just belt out his percussive song. He often assumes a triumphant pose, with one foot grasping one stalk of marsh grass and the other foot grasping another stalk. His typical pose is with legs splayed and anchored midstalk, tail cocked up, while he croons for the favors of a mate.

The Marsh Wren can be found in freshwater marshes, brackish coastal marshes, and even in wet roadside ditches. In Edmonds it is seen almost exclusively in the environs of the marsh. This species is a common summer resident and migrant, but there is a well-documented winter population in the Puget lowlands. During most but the very coldest of winters, the Marsh Wren remains in the Edmonds marsh. Overwintering numbers are poorly understood because the species is quiet and buries itself deep in marshes. The Edmonds marsh seems to come to life in mid- to late-March when the males begin to sing.

For a bird, the Marsh Wren is a low rider. It lives most of its life within eight feet of the ground. The insects that make up its diet are gleaned from the stems of marsh plants or directly from the ground.

When it comes to nesting, this species is the trickster of the marsh. The male builds several dummy nests in his territory. That is why we watch so much harvesting activity of cattail down. The football-shaped nests are anchored to standing cattails one to three feet above water. They are made of wet grasses, cattails, and rushes. The entrance to each is on the side and the nest is lined with plant down. If the female is not satisfied with any of the male’s construction efforts, she will build her own nest. Only the female incubates the four to five eggs but both parents feed the nestlings. The young leave the nest about two weeks after hatching. Two broods a year are typical. The unused dummy nests are thought to provide roosting shelter to Marsh Wrens during nonbreeding seasons.

While the Marsh Wren is certainly a high-spirited, almost joyful, package, it can be aggressive in pursuit of successful breeding. It is known to move around a marsh and puncture the eggs of other nesting birds, including those of other Marsh Wrens.

The Marsh Wren sings multiple variations of its song, both day and night, when breeding. It contains a staccato stutter that is reminiscent of a Geiger counter or the clicking of a rotary dial phone. You can listen to the song of a western Marsh Wren at this link: http://www.xeno-canto.org/158917.

– By Carol Riddell

Carol Riddell, author of our new “Bird Lore” feature, manages the bird education displays, on behalf of Pilchuck Audubon Society and Edmonds Parks & Recreation, at the Olympic Beach Visitor Station.

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