Are Mallards Becoming Nocturnal?

The pattern repeats itself every fall. A cold front brings in a fresh wave of ducks and a rekindled passion among waterfowlers. Some of them fill their duck straps. Others don’t, but the mood is the same. It’s show time. The ducks have finally arrived.

A week later, the skies are empty, save for a few random birds that pass well out of range of every decoy spread in the marsh. It’s as if the ducks have packed up and moved on to safer grounds. But have they? Or are they hunkered down on a refuge or some secret swamp that no hunter knows about? It’s one of waterfowl hunting’s greatest mysteries.

Where are The Birds?

New research sheds light on those disappearing ducks. As it turns out, when food and open water is available, the birds that filled the skies and tumbled into your decoys early in the season haven’t headed for parts south. In fact, they haven’t even left your county. The mallards that were so visible last week just found a place to hide that you and your fellow hunters either can’t go or haven’t discovered. And in some cases, those secret hide-outs are available to anyone with a hunting license and a duck stamp.

“They are real good at keying in on small areas that hunters don’t use,” says Gulf Coast Joint Venture biological team leader Dr. Joe Lancaster.

As a graduate student at Mississippi State University, Lancaster attached VHF transmitters to 113 hen mallards during the 2010 and 2011 hunting seasons and monitored their locations on and around Muscadine Farms Wildlife Management Area. The 1,423-acre property includes a 200-acre refuge closed to all hunting. The rest was open to hunting to varying degrees, but the entire area was closed Monday, Wednesday, and Friday throughout the season.

As it turns out, not all refuges draw ducks. The mallards in Lancaster’s study rarely used the Muscadine refuge. He thinks it may be too small and too close to the hunted areas to give the birds a sense of security. Instead, most travelled about 10 miles to Yazoo National Wildlife Refuge, where they spent the day. (The refuge was closed to hunting during the study.) Others found unhunted wetlands around Muscadine, rarely traveling more than five or ten miles.

Winous Point Marsh Conservancy research biologist Brendan Shirkey conducted a similar study in northwest Ohio. The ducks in his study moved even less, an average of just 500 to 1,000 yards. That didn’t change throughout hunting season. The study area had a large amount of flooded corn impoundments constructed almost entirely for hunting purposes. Ducks flocked to that corn, but mostly at night.

“They basically sat out on a bay on Lake Erie that was closed to hunting during the day. The water was five or six feet deep and there was no aquatic vegetation, so they were just loafing,” he says. “At night, they would go straight to those flooded corn impoundments and stay all night. Almost all of them were gone by legal shooting light.”

Night Moves

The ducks in Lancaster’s study did the same thing. They spent their days in areas where they weren’t being hunted or in areas closed to hunting. Although 35 percent of daytime locations were on public land, only 8% of those locations were open to hunting. At night, they increased their use of hunted portions of Muscadine Farms and surrounding habitat that may or may not have been open to hunting.

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Shirkey wonders if ducks are becoming more nocturnal, which may be why hunters believe there are fewer ducks than we are told. Despite glowing reports of a bountiful fall flight for the past decade or more, a growing number of waterfowlers say they are actually seeing fewer ducks.

“We think ducks have just gotten smarter about avoiding hunting pressure. We suspected they were nocturnal, but not to the extent we found. They can get all the food they want at night, at least in my area, so they have no reason to visit areas open to hunting during the daytime,” he says.

How much food? One calculation found there was the equivalent of 56 million duck energy days in northwest Ohio alone. That is, there was enough planted and natural food to sustain 56 million ducks for one day, or more food than region’s ducks could eat in an entire season. That endless buffet of corn could be why ducks fly and feed less in the day now and more at night.

“That behavior increased over the course of the season. The longer they were hunted, the more they exploited refuge during the day and flooded corn at night,” says Shirkey. “There was just an 10 percent chance that one of the mallards in our study would still be in a flooded impoundment during legal shooting hours after spending the previous night there.”

A Trending Pattern

That’s exactly what happened in Lancaster’s study, as well. Once hunters started showing up to Muscadine Farms WMA in the morning, the birds left. It didn’t matter if the area was open to hunting that day. Lancaster can’t say if the ducks became conditioned to leave when hunters began walking to their spot or if something else played a role in their pre-dawn departure. Whatever the reason, the pattern was clear: By legal shooting light, almost all of the marked mallards were resting safely where hunters weren’t bothering them. In fact, overall mortality of the ducks in his study was as low as 5 percent. Just eight of the 42 marked ducks were killed by hunters during two seasons.

“The majority of hunting-related mortality was on private land, mostly five to ten miles from the public hunting area,” adds Lancaster. “There was no harvest of our marked birds on Muscadine.”

He conducted more in-depth research in the northern Mississippi Delta over two additional seasons (2013 and 2014) and found similar   patterns. Lancaster found daytime use of flooded timber was twice that of nighttime use during hunting season. Some of that timber was open to hunting; some wasn’t. Plenty of birds spent the day on moist-soil habitat, but it was mostly some sort of refuge. Some found flooded crops, rice and soybeans, where they could rest and feed undisturbed. However, ducks tended to increase their use of moist-soil and flooded crops at night when those places were free of hunters.

“They seem to be more tolerant of hunting pressure in forested wetlands than in more open habitats like moist-soil or agricultural habitat. Basically, they can hide better,” adds Lancaster. “Plus, it is their ancestral habitat in the Mississippi Alluvial Valley. They are wired to use that habitat.”

Visit any popular wildlife management area with flooded timber in Arkansas and that will be obvious. Despite heavy hunting pressure, the birds still want in the trees. However, they find pockets of undisturbed water, even if it is just a few hundred yards from a group of hunters. Ducks will continue to use those spots until they either deplete the food source or they get bumped. Shirkey said ducks would key on a specific spot in a specific field, visiting that exact location night after night. Eventually, they would move to a different field. Lancaster found similar behaviors.

“They settled into a pattern that lasted about 7 to 10 days. They would use a safe place during the day and the same agricultural field or moist soil habitat at night. Then they would bump over to a different area and repeat that pattern,” says Lancaster.

Because he used VHF transmitters, Lancaster can’t say for sure what ducks were doing when they were sitting. Those devices only provide an approximate location. Nor can he say exactly what type of habitat they were utilizing beyond forested, moist-soil, agricultural and permanent water categories.

GPS transmitters allowed Shirkey to get a more precise location. Most birds sat on open water in an area closed to hunting, but some did spend the day in places open to hunting.

“They would hide in the cattails on a marsh that was on a club’s property,” adds Shirkey. “They repeated this behavior all season and they only left the area when there was no more open water. Until everything froze up, they had all the resources they needed.”