Mother nature does a great job of keeping good food available for wildlife - when she is left to her own devices. Before humans worked to control them, bison and fires were two forces that saved Rainwater Basin wetlands from becoming choked with large plants, such as cattails and reed canary grass. Today, Ducks Unlimited and partners are using aerial herbicide spraying and a big red tractor to mimic natural events that knocked back the big perennials and gave beneficial plants a chance to grow.

"The next year, it is amazing when everything comes back. Smartweed and barnyard grass are two of the most prominent ones," said John Denton, DU's Nebraska manager of conservation programs. "A healthy wetland can provide carbs, minerals and protein, the kinds of resources birds need to arrive at the nesting grounds in the best shape possible."

DU offers this service for free to landowners, with the help of North American Wetlands Conservation Act grants and contributions from partners, such as the Rainwater Basin Joint Venture. Most of the landowners are under conservation agreements that require them to "disturb" the wetlands regularly. Some have had wetland restoration projects on their properties.

"We can't just do these projects and walk away," Denton said. "Wetlands in the Rainwater Basin need to be disturbed every couple of years, and most landowners cannot do this maintenance work themselves."

Millions of waterfowl rest and refuel in the Rainwater Basin in the spring before heading north to the nesting grounds.

"The ones that arrive in the best shape are the best producers. Waterfowl can load up on carbs from cornfields, but to nest they need the balanced diet healthy wetlands provide," he said.

Ducks are creatures of habit. Denton says If good food is available, birds will migrate to the same place to nest each year. The same is true for their migratory path, traveling through the Rainwater Basin year after year for generations and generations.