Big Lakes, Empty Skies

Why are Minnesota's best waterfowl lakes short on ducks?

By Jason Abraham

Forty-six years ago, Donald Soderlund Jr. and his father left their Twin Cities home in the pre-dawn darkness of an October Saturday. After an hour of driving, they launched a battered 8-foot boat and headed for a small pocket of cattails on a lake just west of the cities. The elder Soderlund pulled a handful of collapsible rubber decoys from his coat and set them on the water.

As mallards, wood ducks, and blue-winged teal buzzed across the decoys, the 12-year-old boy—like many youth on a first duck hunt—became a devotee of waterfowl. From that day forward, his spare time was filled with books about ducks and duck hunting. He bought decoys—one at a time—with weekly paychecks from a part-time job at the Red Owl grocery.

During a visit to the barbershop, Soderlund heard men talking about Pelican Lake, a 2,500-acre wetland near St. Michael in Wright County. He scouted the lake just before waterfowl season that year with a school friend.

Amid dense mats of sago pondweed and wild celery that grew in Pelican’s shallow, clear water, Soderlund found ducks—pintail, canvasback, redhead, and sometimes bluebill (scaup). His trips to the shallow lake grew more frequent. In 1973 he built his home, where he still resides today, on its shore.

As the years rolled past, Soderlund’s love affair with waterfowl never faded. He arranged his work schedule around the fall hunting season and kept detailed records of each outing.

Raining Ducks

When rainfall totals in the 1990s began to exceed historic averages—by up to 40 inches over the decade—in parts of the Midwest, Soderlund, like hunters across Minnesota, began hearing stories about tremendous numbers of ducks hatching in the wide strip of land along the Missouri Coteau in the eastern Dakotas. This so-called duck factory—grasslands studded with wetland basins known as prairie potholes—kicked into high gear. The number of breeding ducks in the north-central United States and prairie Canada jumped from about 25 million in 1990 to nearly 43 million at its peak in 1999, according to the U.S. Fish and Wildlife Service.

In response to the massive waterfowl production in the Dakotas, the USFWS set longer waterfowl seasons and raised bag limits for the Dakotas, Minnesota, and other states in the Mississippi Flyway. In 1997 Minnesota expanded its waterfowl season to 60 days, the longest in 39 years.

But many of these ducks, hatched just a few hundred miles from Minnesota’s western border, simply never appeared over the state’s traditional hunting areas. Hunters like Soderlund, who anticipated huge flocks of ducks on Pelican and other large waterfowl lakes, were often frustrated.

The lack of ducks stopping in Minnesota on their fall migration showed up in annual duck harvest reports. According to USFWS records, the average adult hunter in Minnesota bagged 6.7 birds in a 50-day season in 1996 and in 60-day seasons from 1997 through 2000. That’s more than during dry years, 1986–1995. But it’s about the same number of ducks bagged from 1981 through 1985, when seasons were an average of 10 days shorter.

Meanwhile, from 1996 to 2000, hunters in Louisiana bagged an average of 25 ducks apiece; those in Arkansas bagged 23; and those in Mississippi, 18, according to the USFWS. By 2000 about half of the hunters who responded to a Department of Natural Resources opinion survey reported their overall satisfaction with duck hunting in Minnesota had decreased since 1997.

Disappearing Wetlands

So why did one of the rainiest decades in history produce record numbers of ducks in the Dakotas but no boost in Minnesota’s duck harvest? The answer, according to USFWS wildlife biologist Rex Johnson, can be found by looking at Minnesota’s record of wetland drainage and considering the unintended consequences.

"Wetlands started to disappear almost as soon as people settled in Minnesota. Back in the 1860s and ’70s, the number of sloughs made it hard just to move through the state," said Johnson, who has been leading a project to map restorable wetlands. "There was a lot of incentive to drain wetlands." (The incentive to drain wetlands wasn’t as great in the Dakotas, where prairie potholes were on less arable soils and dried more frequently.)

Throughout the next century, Minnesotans built a wetland-drainage system to expose soils for agriculture and improve transportation. Water from small and medium-sized basins was funneled into larger basins and shallow lakes through a network of ditches and tile lines. Overall, more than 52 percent of the state’s 20 million-plus acres of presettlement wetlands have been lost, according to the Minnesota Wetlands Conservation Plan, a 1997 report issued by state and federal agencies.

The percentage of wetlands lost to drainage has been much greater in southern and western counties, which historically have had the most productive wetlands for waterfowl and shorebirds. In some parts of these intensively farmed counties, 70 to more than 90 percent of wetlands have been drained. Less than 3.5 million acres of presettlement wetlands remain in the southern third of the state.

Lost Buffers

In the 1990s hunters, birders, and wildlife watchers noticed that heavy rainfall quickly resulted in high, murky water in many large, shallow wetlands in the western third of the state—including 10,000-acre Heron Lake in Jackson County and 4,000-acre Lake Christina in Douglas County. On Pelican Lake, Soderlund noted that the formerly shallow and clear water began to rise and become cloudy. Aquatic vegetation began to disappear.

"Back in 1965 there were tons of sago pondweed in the lake and it was shallow. You could walk 200 yards from shore in hip boots," Soderlund said. "Today you’d be over the top of your hip boots less than 20 yards [from shore]."

Without the buffer of small wetlands, large lakes receive rainwater runoff much more quickly, Johnson said. And lake water levels tend to remain higher for longer.

"In some areas of Minnesota, like the Heron Lake watershed, about 85 percent of the wetlands have been drained," Johnson said. "Heron Lake now receives roughly three times the amount of water the lake evolved to convey."

Rainwater runoff also carries phosphorus into lakes. Phosphorus, which is used in fertilizer for lawns and agricultural fields, promotes the growth of algae. Algae, in turn, cloud water and shade vegetation that depends on penetrating sunlight to survive.

Deeper waters allow carp, bullheads, fathead minnows, and other bottom-feeding fish to survive winter and move between lakes more easily. These fish increase cloudiness as they stir bottom sediment. They also feed on the invertebrates that would otherwise reduce algae and provide food for migrating ducks.

With deeper water, less vegetation, and fewer protein-rich invertebrates, the large, shallow lakes attract fewer ducks, geese, shorebirds, pelicans, gulls, and other birds. In addition, Johnson said, the absence of smaller, buffering wetlands means fewer places for ducks to nest and produce young in spring.

Where the Ducks Are

Flocks of ducks that stop in Minnesota on their migration now seem to rely less on large waters and more on small pockets of wetland habitat that have been restored or remain undisturbed, said Tom Landwehr, state conservation director for Ducks Unlimited in Iowa and Minnesota. "The traditional waterfowl hunting areas have not been good. The distribution of ducks is different now," he said. "But hunters who are more mobile and look for the smaller basins with higher-quality habitat can do quite well."

One of those hunters is Patrick Reimer, a former waterfowl guide who lives in Lake Elmo. Reimer maintains a statewide network of contacts to find out where the ducks are and when.

"Basically, we hunt where the ducks are," Reimer said. "We know that if you go to the same place every weekend and expect the ducks to show up, you’re not going to have much luck. You’ve got to move."

On his garage wall, Reimer plots each year’s migration on a map with an erasable pen. His hunting areas include wetlands from Fergus Falls to Marshall and east to Rochester.

The strategy pays off—Reimer and his hunting party say they avoid crowds and often get ducks by finding small parcels of public and private lands that still have good waterfowl habitat.

Priority Waters

While some hunters like Reimer take time to locate the best habitat, Landwehr said many hunters can’t spend as much time pursuing ducks. That’s one reason that restoring large, shallow lakes, where waterfowl hunters have built strong hunting traditions, is a priority for the Minnesota Waterfowl Association, DNR, and USFWS.

While restoring small wetlands that buffer large, shallow lakes is an important step in the process, another critical step is controlling bottom-feeding fish. Since at least 1947, when then– Department of Conservation commissioner Chester Wilson was berated in the Minneapolis Tribune for failing to remove carp from southern Minnesota’s lakes, politicians, conservation groups, and government agencies have provided funding and volunteer labor to kill these fish and limit their movement by blocking waterways that connect lakes.

Control efforts have had some success. For example, in Lake Christina, one of the state’s top waterfowl waters, the DNR used a chemical called rotenone to kill bottom-feeding fish in 1987. In the years following treatment, vegetation covered 97 percent of the lake surface, and staging canvasback ducks increased from 15 in 1984 to 104,000 in 1994, about 20 percent of the North American canvasback population.

But it wasn’t a long-term solution. Carp, bullheads, and several game fish species survived the treatment or found their way into the lake and repopulated it.

"The 1987 treatment showed us that we have the tools to successfully rehabilitate large, shallow lakes," said Ray Norrgard, DNR wetland wildlife program leader. "To keep fish from returning, it’s critical that we reduce their ability to move between lakes by creating fish barriers."

The DNR, DU, and other partners will construct fish barriers on Christina’s inlets and treat the waters again this fall. Funds will come, in part, from a recent Legislative Commission on Minnesota Resources grant to DU to improve wildlife habitat on shallow lakes, including $450,000 for reclamation of Lake Christina.

Conservation Practices

To reduce the amount of water and pollutants that enter large lakes will require changes in land-use practices and restoration of smaller wetlands that act as buffers.

In 2001 the DNR, USFWS, MWA, and DU produced a plan called Restoring Minnesota’s Wetland and Waterfowl Hunting Heritage. Signs of progress include more than 15,000 acres of wetlands restored or protected in cooperation with conservation groups since 2000, and 91,000 acres of wetland habitat that continue to be enhanced by water-level management.

Although much remains to be done to improve Minnesota’s wetlands, conservation in Minnesota’s agricultural regions has improved significantly since the mid-1980s, said Wayne Edgerton, DNR agricultural policy director. Prior to the introduction of the federal Conservation Reserve Program in 1985 and state programs that paid farmers to set aside marginal cropland, Minnesota’s agricultural practices were driven by commodity prices, which often forced farmers to put as much land into production as possible.

"We’re definitely in a different place today," Edgerton said. "Conservation organizations like Pheasants Forever, DU, the Izaak Walton League, and others have influenced farm policy on a national level."

Tim Bremicker, director of DNR Wildlife and a long-time waterfowl hunter, is hopeful about the future of the state’s wetlands, provided that government agencies, conservation groups, politicians, and individuals continue to work toward improving land-use practices.

"With better agricultural policy that promotes retention of grassland and protects lands from erosion through conversion to grassland or pasture—through CRP or the Conservation Reserve Enhancement Program—and powerful wetland protection measures, I remain cautiously optimistic about wetlands and waterfowl in Minnesota," Bremicker said.

Bremicker, like all waterfowl hunters, knows that duck populations change from one year to the next depending on factors that no one can influence—rainfall, weather patterns during fall migration, and, sometimes, just luck.

Bremicker said there will be times when less rainfall in the Dakotas, combined with declining waterfowl habitat in Canada, will likely mean lower duck populations, which would force the USFWS to set shorter seasons and reduce bag limits for duck hunters in Minnesota and other Mississippi Flyway states.

"The important thing is to focus on the things we can influence," he said. "We have a tremendous shallow-lake resource in this state, unique in both numbers and quality. To not protect and manage those resources would be to deny our promise and obligations."

Jason Abraham is a DNR staff writer for the divisions of Fisheries, Wildlife, and Ecological Resources.