Saving the Duck Factory

Ducks don't just need water. They need extensive grass adjacent to wetlands to nest and incubate eggs. There's no better mix of grass and water than North Dakota's prairie potholes, but even great habitat isn't enough sometimes. Predators--skunks, raccoons, foxes and coyotes--can be hell on nesting ducks. That's where Delta Waterfowl comes in. In order to find the duck nests, you have to find the nesting hens. The best way to do that is by dragging a log chain across the prairie.
The chain is pulled between two four-wheelers, and when the clanking, jerking chain comes close to their nest, hen ducks flush.
Researchers then walk gingerly around the area of the flush to find the nest, well hidden in the dense grass.
A shoveler nest
Researchers John Devney and Mike Buxton log the nest's location.
An orange rod will help researchers locate the nest in coming weeks to assess hatching success.
And a unique number will allow researchers to see if this nest site is used year after year.
Buxton then "candles" the eggs, looking at them through a dark tube to see how developed the yolk is. By holding the egg up to the sun he can see if an embryo is starting to develop.
An undeveloped yolk looks uniformly round. As the embryo develops, the dark spot on the yolk gets larger.
This township is not being trapped for predators, so researchers are comparing nest success here with that of nests in similar habitat that's being extensively trapped for mammalian predators.
The presence of this abandoned homestead worries Delta's John Devney.
These structures are perfect habitat for skunks and raccoons and other predators that then raid nests of waterfowl and upland birds in the surrounding grasslands and wetlands.
Sure enough, the next nest we discovered had been raided, probably by a skunk though it could have easily been a raccoon. Populations of both species have increased in recent years as small-grain production has boomed and their range has steadily marched north and west.
Most people mistakenly believe ducks nest over water. Instead, almost all species nest in grass. We found several nests in dense grass right alongside county roads.
The tool to find these roadside nesters is a variation of the chain drag. In this case it's a boom that lowers rattling paint cans into the borrow ditches of county roads, spooking hens off their nests.
If necessity is the mother of invention, these duck researchers are needy, indeed. This contraption looks pretty homespun, but it's the perfect device for flushing birds off nests that otherwise would never be discovered.
But for grassland "trolling," the log chain is the tool for the job.
The chain is able to cover large swaths of grass in each pass, making short work of even large blocks of CRP cover.
Here, Devney and Buxton repack the chain in a milk crate so they can drive to the next site.
Most of the areas being assessed by Delta are either grassland easements maintained by the U.S. Fish & Wildlife Service or Waterfowl Production Areas managed by North Dakota Game and Fish.
And the researchers themselves are hard-core waterfowlers, as shown by their bumper-sticker allegiances.
The next site is one that's been trapped intensively. It will be interesting to see how it differs from the untrapped site.
Our first nest is much further along than the earlier nests. We can tell by the copious amount of down in the nest bowl, a sign that the hen is done laying and is now actively incubating the eggs.
Buxton prepares to assess this blue-winged teal nest.
It's not just duck nests that benefit from predator trapping. We also find a sharp-tailed grouse nest.
And a snipe nest, so far along that the little chick is just starting to break out of the shell. Here Devney points to cracks in the end of the egg where the chick is pipping. It will be hatched within hours.
We encounter several predator traps. Here a clutch of chicken eggs is being used as bait, inside a ring of foot-hold traps designed to catch raccoons or foxes.
This Conibear trap is inside a wooden box, with a can of cat food as bait. It's designed to catch skunks or raccoons.
Will predator trapping put more ducks in the marsh? It's hard to say--habitat remains the biggest factor in waterfowl success--but by allowing more chicks to hatch, North Dakota will remain America's most productive duck factory.