Safe Houses - Thanks to a conservation group, Minnesota mallard hens will find more predator-free places to lay their eggs
by Chris Niskanen
St. Paul Pioneer Press, March 13, 2008

The ice is more than 2 feet thick in western Minnesota, but spring is drawing nearer. Last week, a few migrating mallards were already winging into open water on rivers in Minnesota's western 'prairie pothole' region, the duck-rearing epicenter of the state.

Once the wetlands become ice-free, tens of thousands of mallard hens will search out nesting sites in the grasslands. (They don't nest in cattails, contrary to popular belief.)

But finding a good nesting spot won't guarantee ducklings. Predators such as raccoons, skunks and foxes prey on the vulnerable hens and their eggs — and on average, only 15 percent of mallard eggs laid in Minnesota become ducklings. At that rate, scientists say, Minnesota's mallard population isn't growing — it's barely staying even.

That's why Matt Chouinard, an employee of conservation group Delta Waterfowl, spent the winter erecting and repairing hundreds of "hen houses" in western and southwestern Minnesota.

Created by Delta to keep predators away, these wire cylinders, padded with grass, are placed on a pole over water. Studies show that using the houses increases mallard nest success rates to 93 percent in Minnesota.

This year, the Minnesota Department of Natural Resources is paying Delta $70,000 to upgrade nearly 400 hen houses and put up about 200 new ones. Next year, the DNR will pay another $100,000 to add 300 more.
It's an unprecedented effort to use artificial structures to bolster mallard production in the state.

"The goal is to have 900 structures available for nesting over the next year, about double what we have now," said Ray Norrgard, the DNR's wetland wildlife program leader.

They'll be in 10 counties: Grant, Ottertail, Stevens, Pope, Big Stone, Lincoln, Lyons, Murray, Jackson and Cottonwood.

"But I don't think anyone see this as a panacea for our duck-production problems," Norrgard said.

"The nests on poles over water are hard for predators to climb," said DNR waterfowl researcher Dave Rave, who conducted an eight-year study of hen houses in Minnesota. "There are very few predators that will find the nest."

Chouinard, who completed his master's degree on hen houses in Minnedosa, Manitoba, said small predators are more prevalent on today's prairies than in the past, and shrinking grasslands make it easier for predators to find duck nests.

The Conservation Reserve Program launched in the mid-1980s, which pays farmers to idle croplands, has helped dramatically, but pastures and other grasslands continue to disappear.

"Coyotes eat small mammals, but foxes eat ducks. The big three duck predators are skunks, raccoons and foxes," said Chouinard. "They'll eat duck eggs and ducklings, as will ravens, crows and badgers. Foxes are pretty tough on mallard hens, too. When they're on the nest, hens are susceptible to predators. I've seen studies where 30 percent of the nesting hens are killed in a season."

COST

In Canada, creating and maintaining hen houses — replacing grass and keeping them in good repair — winds up costing about $10 per fledged duck.

"That might seem like a lot, but it's cheaper than a lot of other activities for the sole purpose of raising mallards," said Chouinard. "It's cheaper than buying a quarter section of grasslands, but you don't have the other benefits for other wildlife."

In Minnesota, hen house costs are $23 per fledged mallard, Rave said. But he still considers the houses cost-effective.

"Hen houses are one of the cheapest ways for producing mallards," he said. "They help bolster local mallard populations in areas where we have wetlands, but our limiting factor is the amount of grasslands we have."
The hen house program is part of a project called the Working Lands Initiative in Minnesota, "which is part of a general effort to work with private landowners to create large wetland complexes," Norrgard said.
Some of the hen houses are being placed on private lands, though most are being put on public lands, Norrgard said.

"IF WE CAN SHOW THESE ARE SUCCESSFUL ON THE LANDSCAPE, WE CAN BUILD INTEREST BY PRIVATE LANDOWNERS AND CLUBS TO DO THE SAME THING," NORRGARD SAID.

INSTALLATION

Last week, Chouinard, who lives in Morris, Minn., was installing hen houses near Appleton, Minn. The weather was warm, but the ice was nearly 3 feet thick.

"It's frozen right to the bottom of a lot of wetlands," Chouinard said.

He cut holes in the ice in a wetland and pounded a steel posts into the muck. Then, he mounted hen houses on separate poles and attached them to the ones driven into the wetland.

To cut a hole in the ice, Chouinard uses an auger, and he periodically hits the bottom or other obstacles.

"I've probably gone through five or six auger blades and sharpened many others," he said. "I drill at least three or four holes for each hen house. We've had some rough weather this winter, but I've managed to avoid frostbite."

Chouinard, a native of southwest Missouri, said he enjoys working in the wetlands and installing structures that will help Minnesota's struggling mallard population. In the coming weeks, those mallards will be showing up in droves to find a new place to raise their ducklings.

"I already saw a pair of mallards on a river the other day," Chouinard said. "The weather is changing. The snow is really starting to melt."

Copyright 2008 St. Paul Pioneer Press. Republished here with the permission of Chris Niskanen and the St. Paul Pioneer Press. No further republication or redistribution is permitted without the express approval.