What is a Wetland? And Other Habitats Great Lakes Birds Need

A beginner’s guide to the areas of water, and surrounding land, that birds and people rely on across the Great Lakes region

From the Great Lakes coastal wetlands to inland marshes and ephemeral streams - millions of birds depend on the region’s water for shelter, rest, and nourishment. To celebrate World Water Week (August 23 – 27), we are breaking down some of the top water habitats that birds need. Discover the difference between a wetland and a marsh, the far-reaching benefits of hemi-marsh habitat to birds, and why streams are important to birds even if they don’t run year-round. 

What is a wetland?

Simply put, a wetland is an area of land saturated with water, which may be wet year-round or only seasonally. Wetlands are often distinguished by the presence of aquatic plants, which adapt to live in saturated soil.

There are many types of wetlands including marshes, lakes, lagoons, ponds and swamps – to name just a few! The Great Lakes region has approximately 300,000 acres of coastal wetlands in the U.S. alone.

These areas between land and water provide critical habitat for birds who rely on them as places to rest during their long migration journeys, and to nest and feed their young.  Birds that have suffered population declines, such as the Black Tern, Least Bittern, and Common Gallinule, depend on a network of healthy wetlands throughout the Great Lakes region in order to prosper.

Wetlands are also important to local communities. They serve as natural water purifiers that absorb pollutants to keep the water in inland lakes and streams clean. By storing water, wetlands also operate as natural flood control to protect local communities from flooding and drought and help buffer communities from a changing climate.

What is a watershed, and do I live in one?

No matter where you are, everybody lives within a watershed. A watershed is an area of land where all of the water that falls on it drains into a particular waterway like a river or lake. In the Great Lakes region, the aptly named Great Lakes Basin encompasses all of the watersheds that drain into the Great Lakes, more than 94,000 square miles.

Over the past half century, human activity surrounding the Great Lakes basin has significantly degraded habitats and water quality, and as a result, many marsh bird populations are in steep decline, with some regional population declines as high as 80 percent in recent decades. The good news is that we know how to save them.

More than two-thirds of the original coastal wetlands in the Great Lakes have been lost to agriculture, industry, or human residence. To help put our conservation work where it is needed most, we have identified the most important wetlands for our region’s vulnerable marsh birds. Learn more about our vision plan to restore the Great Lakes region for birds and people.

What is a marsh?

A marsh is a type of wetland that is mostly open and is dominated by vegetation that grows out of the water and is rooted on the wetland floor, floating plants such as waterlilies, and vegetation that live completely underwater. 

Marshes are an oasis for a wide variety of animals ranging from fish, amphibians and birds. Marsh birds such as Sora, Virginia Rail, and Least Bittern are all regularly found in marshes during the spring, summer, and fall, but their stealthy behaviors often prevent them from being detected by people.

Marsh birds can serve as excellent indicators for the health of wetlands and by surveying their populations and habitats, scientists gain key insights into current conditions and trends that inform restoration work that will be the most beneficial for birds and people.

To better understand marsh bird population trends, Audubon Great Lakes leads Marsh Bird Surveys across the Great Lakes region. The Audubon Great Lakes Marsh Bird Data Hub showcases efforts and results of marsh bird monitoring at 32 sites across the Calumet region in Illinois and Indiana. 

What is hemi-marsh?

A hemi-marsh is a type of marsh that is roughly equal parts open water and emergent vegetation or plant life. Since hemi-marsh inherently provides a diverse habitat structure, it attracts a variety of birds and other wildlife species. Great Lakes birds such as the Least Bittern, Pied-billed Grebe, and Marsh Wren rely on hemi-marshes year-round for cover, nesting habitat and food.  

Since hemi-marsh is so valuable and can provide habitat for a wide variety of species, land managers and conservationists seek to maintain, protect, and restore hemi-marsh across the Great Lakes landscape. Land managers use levees and water control structures to manipulate water levels throughout the year with the goal of maintaining this delicate but important balance of water and plant life.

What is an ephemeral stream?

Ephemeral streams only flow after precipitation events like rainfall or snowmelt.

Whether a stream flows year-round or a few weeks per year, it supports wildlife, native vegetation, and local communities.  Ephemeral streams are important to birds like the Prothonotary Warbler, which depends on habitat like ephemeral streams to rest and refuel during its migratory journey covering thousands of miles.   

Ephemeral streams also provide clean water to wildlife and people while offering protection from flooding and helping to prevent nutrient run-off, which contributes to harmful algal blooms in the Great Lakes.

-  Tristen Ortiz, Communication Intern, Audubon Great Lakes

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