Monday, June 1, 2015

A River of Birds: Supporting the Mississippi Flyway

Waterfowl at Great River National Wildlife Refuge. Photo by USFWS.
Happy birthday to Great River National Wildlife Refuge and Middle Mississippi River National Wildlife Refuge! While these stretches of the Mississippi River were previously part of Mark Twain National Wildlife Refuge, they became individual refuges 15 years ago this week.

Regardless what you call these areas, migrating birds consider them the heart of their journey between breeding grounds to the north and overwintering areas to the south. These refuges form part of what is known as the Mississippi Flyway - a migration corridor for more than 325 species.

Running between Missouri and Illinois, Great River National Wildlife Refuge is a mosaic of floodplain habitats historically found along the Mississippi River. Slow moving backwaters, floodplain forests, wetlands, sedge meadows and grasslands combine to provide food, shelter, and resting areas for nearly 300 species of birds during migration.

Middle Mississippi River National Wildlife Refuge lands were purchased in response to the great flood of 1993 and are unique in the refuge complex. The refuge tracts lie within the uncontrolled portion of the Middle Mississippi River, below the confluence with the Missouri, where river levels are not regulated by the lock and dam system. Water levels may fluctuate greatly in this "open river" section of the Mississippi, and frequent flooding occurs on these lands.

Persistent flood conditions along Middle Mississippi River have caused dieback in some of the trees in recent years, making it ideal for cavity nesters such as wood ducks, prothonotary warblers, and red-headed woodpeckers.

The Great River Refuge Long Island Division, which is situated on the Illinois side, includes a complex of forested islands. These islands, taken collectively, add up to the largest contiguous bottomland hardwood forest in the area. The size and diversity of trees makes the area unique along this portion of the upper Mississippi River and are important for forest bird species like the cerulean warbler, woodpeckers, eagles, and red-shouldered hawk.  
Each week during fall and spring migration, our biologists count waterfowl, shorebirds, wading birds, and marsh birds like sora in the Delair Division of the Great River Refuge. These migration surveys help us to estimate the number of birds seen on the refuge and get an idea for how populations are responding to our habitat restoration efforts. The survey numbers are also used to note general migration trends as birds stop to rest and feed on the refuge through the years.

Visitors primarily come to both of these refuges to hunt and fish, but also to watch wildlife and take photos. If you’re ever in the area, stop by and enjoy the view!