MARK FREEMAN

Mail Tribune via Associated Press

MEDFORD, Ore. (AP) -- A fledgling group of duck and goose advocates is hoping a simple contraption of metal and grass will make a big splash in a waterfowl wonderland that is smack-dab in the middle of the Agate Desert.

The new local chapter of Delta Waterfowl is taking a page from its Midwestern brethren by installing a string of "hen houses" designed to provide a safe nesting haven for mallards and other diving ducks at the Denman Wildlife Area in White City.

The houses are little more than heavy-gauged wire wrapped into a tube, stuffed with fresh grass and suspended over water atop a telescoping metal pole.

The duck condos will provide these ground-nesting birds with protection from predators during the upcoming nesting season for local waterfowl. Steve DeBerry and his fellow waterfowlers will install a dozen of them Saturday at the wildlife area -- the first such structures ever installed in Southern Oregon for mallards.

"It's definitely unique to the area," says DeBerry, an Eagle Point resident who started the Delta Waterfowl chapter here a year ago. "We're hoping we can succeed with this and put even more out there next year."

For decades, waterfowl enthusiasts have installed wood-duck boxes and nesting platforms for Canada geese to help improve nesting success of resident birds throughout the region.

Even though mallards are the most abundant duck species in North America and the top table fare among waterfowlers, precious little has been done artificially to boost their nesting success.

"Wood-duck boxes seemed to make sense," says Matt Chouinard, a Delta Waterfowl biologist in Minnesota who has helped the group install close to 10,000 hen houses in the upper Midwest. "Wood ducks nest in cavities, so you put up the box and it fits the bill."

But mallards are altogether different critters.

Mallards nest in the tules and grasses around lakes, ponds and marshes. The nesting hens and their eggs are easy pickings for skunks, raccoons, foxes and all sorts of other small critters that have mallards high on their spring menus.

"Since mallards typically nest in grass, they'd be lucky to have 15- to 20-percent nesting success," Chouinard says.

After years of testing, Delta Waterfowl biologists created the design in the early 1990s.

The heavy-gauge wire is strong enough to withstand the weight of a perched goose, but its 11-inch opening is too small for geese to claim as their own.

The fresh grass provides a nesting space for mallards, which won't drag fresh grass inside like other birds do.

Suspending the hen house over water creates a formidable obstacle to ground predators. And the metal pipe means the most eager mammal would struggle to climb it.

The results are impressive.

At first, only a few of the houses are occupied, Chouinard says. After a few years, the birds seem to figure out the advantages of condo living, he says.

After a few years, the condos have an occupancy rate, on average, of about 80 percent and their nesting success consistently ranges between 60 percent and 90 percent, Chouinard says.

"For a long time, I don't think people realized how adaptive mallards can be," he says.

The Denman Wildlife Area is the most-visited public hunting area in the valley, and its location along the Rogue River in the heart of the White City industrial area creates a 1,760-acre refuge for wild birds and those who stalk them.

The Oregon Department of Fish and Wildlife floods and farms large tracts of the wildlife area to provide food and habitat for waterfowl, but resident birds still battle predators there.

Denman manager Clayton Barber says he welcomed Delta Waterfowl's hen-house proposal.

"From my perspective, any success we have here is a bonus," Barber says. "If it produces any birds, it's a success in my book."

DeBerry says this is the first project undertaken by the new chapter, which sports about a dozen active members.

They used money raised from last year's inaugural banquet to buy materials for the houses, which cost about $40 apiece to construct.

Volunteers will meet Saturday to place the first dozen hen houses in Whetstone Pond and along pockets of marsh habitat along Whetstone Creek.

The houses will be monitored intensely through the breeding season.

"If we have a pretty good success rate, of course we'll put more out there," DeBerry says. "We're looking at upwards of 40 more hen houses."

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Information from: Mail Tribune, http://www.mailtribune.com/

Copyright 2010 The Associated Press.