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Cofrin Center for Biodiversity

American Bittern

Keen-eyed botanist Gary Fewless spotted this American Bittern (Botaurus lentiginosus) in the Cofrin Arboretum. American Bitterns used to be fairly common in the large marshes on the west side of the Bay of Green Bay, nesting in cattails and in sedge meadows in Atkinson, Sensiba, and Peters marsh. In recent years, as Phragmites australis has invaded and replaced cattails in much of the marshes in northeast Wisconsin, we have seen a decline in the numbers of nesting pairs of American Bitterns.

The loss of large wetland areas to development and degradation by invasive plants like Phragmites and pollutants has taken a toll on bittern populations in the United States. Overall American Bitterns are half as common as they were 40 years ago.

American Bittern

American Bittern at UW Green Bay

This individual is the first to be sighted on the UWGB campus and is probably a young bird that is looking for suitable habitat as it prepares to migrate. According to Richter Museum Curator Tom Erdman, these individuals often return to a location they sampled the previous fall. So perhaps this one might return to nest in the spring.