Study aims to determine most productive nesting cover for ducks

(Brad Dokken/Grand Forks Herald/MCT)
Scott James (left) and Ryan Haffele (far right) drive ATVs while dragging a...
Story by Brad Dokken
Grand Forks Herald
July 11, 2011
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LAKE ALICE NATIONAL WILDLIFE REFUGE, N.D. — The mallard hen exploded from the thick grass, startling the bejesus out of an unsuspecting reporter who came to his senses just in time to see the clutch of eggs concealed at his feet.

The encounter was more jolting than a stiff cup of coffee, but aside from a close call with cardiac arrest, no harm was done to human, duck or nest.

“Step on an egg, and it’s a case of beer for the boys,” Ryan Haffele joked from a few feet away. “That’s our rule.”

Whew . . . that was close.

A graduate student at Southern Illinois University, Haffele, 24, is overseeing a research project at Lake Alice and other U.S. Fish and Wildlife Service lands in the Devils Lake area looking at duck nesting success and whether certain types of upland cover are more conducive to producing birds.

And on this 158-acre field, the largest of 14 they’re monitoring throughout the Devils Lake wetland district, duck nests are everywhere.

“It’s nuts out here,” Haffele said.

Haffele and assistant Scott James, an SIU graduate working for the Fish and Wildlife Service in Devils Lake this summer, had already been “nest dragging” the field about three hours this mid-June Thursday morning. It’s a common technique in waterfowl research that involves dragging a 150-or-so-foot length of chain between two ATVs to roust hen ducks from their nests.

The chain rides over the nest and doesn’t harm the eggs.

They’ll drag each field once a week until nesting season wraps up in early July. Until then, the crew’s at work “every day it’s not raining,” Haffele said, adding he’d had only two days off since May.

Days in the field start early, and Haffele said they typically start dragging by 7 a.m. and wrap up mid-afternoon. That coincides with the best times to catch the hen on her eggs.

Once they’ve rousted a hen, they mark the nest, both with stakes and GPS coordinates, to monitor the eggs and record the type and abundance of vegetation at each site.

They also record the species, the stage of egg development, time of the visit and, ultimately, whether the nesting effort was successful.

There’s been lots of success at Lake Alice. As of mid-June, Haffele said they’d found 228 duck nests on the 158-acre site, and 196 of those nests were still active and capable of hatching birds.

Stakes marking each nest dot the field.

“This field is doing real well,” said Haffele, who’s in the second year of the study and his third field season at Devils Lake. “The success I found out here last year was unreal.”

Roger Hollevoet, manager of the U.S. Fish and Wildlife Service district office in Devils Lake, said the nesting success at the research sites is a marked contrast to his days as a graduate student in the 1970s.

Abundant water is a factor, he said, along with a decline in predators such as fox and an increase in coyotes, which don’t tolerate their smaller cousins and have prevented numbers from recovering.

And then there’s the habitat. Hollevoet said he remembers working a site near Lakota, N.D., in the 1970s and finding one duck nest every 14 acres. There was no Conservation Reserve Program, and the only areas with enough habitat to support nests were railroad grades and roadsides.

“Here, it’s two nests an acre,” Hollevoet said. “I’m hoping it’s the cover.”

“The cover” is where Haffele’s study comes into play. The 14 fields in the study area either have “dense nesting cover,” a standard mix that includes wheatgrass, alfalfa and sweet clover, or native perennial grasses.

The study aims to determine if either of the two cover types is more conducive to producing ducks.

Hollevoet said dense nesting cover — or DNC, as it’s called in management circles — has been used among waterfowl managers since the 1970s. But in recent years, he said, there’s been a push to get the mix off the landscape in favor of native perennial grasses similar to what covered the prairies before settlement.

Both have pros and cons. The native grasses cost about $300 to establish, while DNC costs about $30 an acre. Less upfront cost, to be sure, but dense nesting cover has to be replaced after about 10 years and requires more maintenance to keep noxious weeds at bay.

“I don’t want to spend money on noxious weeds,” Hollevoet said. “I want to spend it on new cover.”

Still, Hollevoet said he’s not ready to abandon dense nesting cover in favor of the more expensive native grasses quite yet. The study, he said, will help determine which cover type managers ultimately use.

“I said, ’We’re not going to just go blindly into this,”’ Hollevoet said of the switch to native perennial grasses. “We’re going to find out if it’s any good or not.”

Ultimately, Hollevoet said he envisions a mix of the two cover types in long-term management plans, especially in the saline soils found in parts of the Devils Lake wetland district.

“With the DNC mix, some of these are very salt tolerant,” he said. “There’s no point putting the expensive mix where DNC will thrive and these other species will struggle.

“I hope the idealists coming up behind me don’t get rid of DNC because it’s some good stuff. It’s got a lot of science behind it.”

At this point in the study, at least, the ducks don’t seem to show a preference.

“I haven’t noticed too much difference,” Haffele said. “Last year, there was absolutely no difference between the two cover types.”

Both cover types hold lots of ducks. As a waterfowl manager, that’s exactly what Hollevoet wants to see.

(c) 2011, Grand Forks Herald (Grand Forks, N.D.).

Visit the Herald on the World Wide Web at http://www.grandforksherald.com/.

Distributed by McClatchy-Tribune Information Services.

Brad Dokken

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