Improving Agassiz Valley for Birds

Northwest Minnesota is an important place for Minnesota’s birds as a unique transition area that bridges the prairies to the south and west to the eastern forests. 

Historically, the area was dotted by shallow pothole wetlands, but agricultural development has greatly changed the landscape. Today, shallow, artificial lakes act as flood-control reservoirs, otherwise known as impoundments. These managed wetlands serve as critical stopover and nesting habitat for waterbirds as they migrate and breed.  However, these impoundments are susceptible to being overtaken by invasive, hybrid cattail that are not native to Minnesota. The aggressive plant has reduced habitat quality by choking areas that previously had open water and outcompeting native plants.

The Agassiz Valley Impoundment, near Warren, MN, used to have very little hybrid cattail and provided a unique area in an agricultural matrix that attracted birds and wildlife. But the hybrid cattail continued to expand further into impoundment, choking shallow areas of open water and mixed vegetation limiting its value to waterbirds.

We developed a management regime for non-native invasive hybrid cattail in the Agassiz Valley Impoundment to improve its value to waterbirds and promote native vegetation. This effort has been a collaboration between Audubon and the Middle-Snake-Tamarac Rivers Watershed District. Audubon provided project management, funding for management actions, and bird surveyors while the Watershed District provided maintenance to the Impoundment and staff time to monitor and adjust water levels.

Throughout the project, bird surveyors were able to document several firsts for the impoundment as habitat transitioned. One exciting discovery was that Black Terns were utilizing the impoundment for nesting and raising their young! Several pairs of Red-necked Grebes, a Species of Greatest Conservation Need in Minnesota, have also successfully raised chicks at the impoundment.

Black Tern , Red-necked Grebe Black Tern Gulls and Terns Play Black Tern typical calls sound Red-necked Grebe Grebes Play Red-necked Grebe song sound

Audubon Upper Mississippi River is worked closely with the Middle-Snake-Tamarac Rivers Watershed District, the manager of the Agassiz Valley Impoundment, to develop wildlife enhancement elements that could be incorporated into the future management of the impoundment. With continued water level management by the Watershed District, this refuge for birds and wildlife can continue to provide high quality habitat for years to come.

If you find yourself in northwestern Minnesota, come visit the Agassiz Valley Impoundment for some excellent bird watching!