MARSH WREN IN THE MARSH

Marsh Wren is a secretive winter visitor to the larger Chico marshes where they are heard more often than seen. Although this species breeds in northern Colorado, it does not do so on the Chico. A Nebraska study comparing the songs of eastern Marsh Wrens with western Marsh Wren led the author to conclude there are really two species of Marsh Wren based on vocalizations and not plumage. Western type Marsh Wrens, the ones breeding in Colorado, sing well over 100 song types whereas eastern types sing fewer than 50 songs and there are some subtle differences in the introductory notes between eastern and western birds. The best way to see a Marsh Wren at Chico is to slowly approach a calling bird and then try to imitate its call, but only once or twice. This method seems to drive the wrens crazy and eventually one will fly up on a cattail stalk to see where the competitor is located. Here is today’s result with this method. They are always in the wet portions of the marsh so getting really close usually doesn’t happen.

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