St. Louis River Estuary Restoration

On the border of Wisconsin and Minnesota is the St. Louis River Estuary, an expansive complex of wetlands that provide habitat for migrating waterfowl, shorebirds, and songbirds as well as declining species of marsh birds.  

The St. Louis River Estuary and its surrounding region has been identified by Audubon scientists as one of the 12 most important coastal wetland regions across the Great Lakes that are most important to conserve or restore for vulnerable marsh birds. 

The Estuary has suffered from a legacy of industrial pollutants and was once one of the most polluted waterways in the United States. Despite this, many of the intact marshes remain in relatively high-quality condition, supporting exceptional bird and native plant diversity, including wild rice, during migration and nesting seasons.  

More than 240 bird species have been recorded within this Audubon Important Bird Area (IBA) and its numerous bays, islands, wetlands, barrier beaches, and forested areas. Many of these species are facing steep population declines. Black Terns, once common, have not bred in the estuary since the 1990s. 

Marsh bird species including American Bittern, Least Bittern, Black Tern, and Yellow-headed Blackbird, all of which are Wisconsin Species of Greatest Conservation  depend on a unique habitat commonly referred to as hemi-marsh (roughly equal parts water and plant life), which has drastically decreased across the Great Lakes region due to development and an increase of invasive species, in parallel with population declines of these species.  While fluctuating water levels are generally favorable for marsh birds because they help wetland plants thrive, major water fluctuations intensified by a changing climate have disrupted the delicate conditions that hemi-marsh habitat needs to thrive in some areas of the St. Louis River Estuary.  

Our work in the St. Louis River Estuary region is  focused on restoring the highest- opportunity wetlands. At Allouez Bay, our first and largest project in the region, we restored hemi-marsh conditions by removing invasive cattails that made it difficult for marsh birds to thrive. Audubon and partners will continue to evaluate how marsh birds are responding to conservation, which will inform future restoration strategies throughout the Estuary to protect the area’s important wetlands and safeguard them against impacts of a changing climate.