By Dan Van Schaik

Depending on your location, we are only about four months away from fall migration. That is also the length of the growing season for most popular plant varieties that attract ducks and geese to our management areas. Whether you favor natural aquatic forages or cultivated food plots, now is the time to get those greens growing. Chances are, your lakes and ponds are within proximity to at least one established migratory corridor that connects a series of major waterways known as staging areas.

Lowered impoundment with beaver-proof drain.

When it’s time, most waterfowl will just be passing through your region on their journey southward to overwintering grounds. Migration is a hazardous undertaking demanding high energy intake along with protection from harsh elements and predation. This means most of our efforts should concentrate on hosting these seasonal birds by providing food and refuge. Chances are, your lakes and ponds are within proximity to at least one established migratory corridor that connects a series of major waterways known as staging areas. Staging areas allow birds to rest and regroup during their passage, which often results in extended stays on peripheral food and freshwater sources.

Waterfowl typically represent the game portion of waterbirds that include ducks, geese, swans, and cranes. Because they are the most popular target species for hunting, ducks and geese get most management attention.

Ducks coming down the flyway can be grouped by feeding preferences and behavior:

1. Dabbling ducks feed on or near the water’s surface—mallard, pintail, gadwall, widgeon, greenwing and bluewing teal, shoveller, and wood duck; and are predominately plant feeders.
2. Diving ducks feed under the water’s surface— scaup, ring-necked, bufflehead, redhead, canvasback, merganser, and goldeneye; and may be plant or animal feeders.
3. Perching ducks are capable of landing on and nesting in trees—wood duck, fulvous, blackbellied, and are also both plant and animal feeders.

The most obvious external features that distinguish diving ducks from nondiving are relatively larger toes with broader webs, and shorter legs placed farther back on the body. These physical adaptations facilitate a more active and continuous life in the water. Diving ducks don’t do well on land and usually seek deeper, broader water. Perching ducks have their legs and clawed feet positioned farther forward on the body than the dabbling ducks in order to grasp and balance on tree limbs. Dabbling ducks, with legs and feet positioned in between that of divers and perchers, prefer dipping for foods in shallow water, but are fully capable of walking on land.

Goose species may include: snows, blues, whitefronts, and Canadas. Inland geese are primarily herbaceous grazers that take advantage of agricultural farm crop residue found along the flyway. They frequent corn, soybean, peanut, wheat, sorghum, rice, and legume fields. Their large webbed feet and strong legs positioned mid-body are well adapted to locomotion on land and water.

Waterfowl are particularly interested in food sources that are safely attainable from open lake or pond sites. They land on water, and then wade or walk into shallow feeding areas. Some preferred natural aquatic plant forages are: arrow arum, river bulrush, carex, scirpus atrovirens, flowering rush, spatterdock, water lily, Joe pye-weed, spike rush, rice cutgrass, swamp milkweed, water plantain, smartweed, arrowhead, pondweed, duckweed, pickerel-weed, and panicums. Numerous studies conducted on lakes and ponds of favorable depth and character of bottom demonstrate the potential to produce over 6.5 tons per acre of such preferred aquatic vegetation annually. In addition, there is the by-production of minute animals (insects, mollusks, crustaceans, and other invertebrates) that eventually become available to a variety of wildfowl through the food chain.

Although waterfowl have a high tolerance to a wide variation in salinity levels, they most often seek secluded freshwater reservoirs for resting and dabbling activities. Some important cover
plants used by ducks and geese are: quackgrass, bluegrass, annual weeds, phragmites, tall reed, cane, grain stubble, sedges, brome, bulrush, aster, cattails, and willow.

Unfortunately, promotion of these forages and cover waterweeds often conflict with fisheries programs and other recreational uses of many lakes and ponds. In addition, wild forage plants cannot compete with the caloric value of cultivated grain crops when assessed in terms of a single food source. For example, it takes 15,000 smartweed seeds to produce the same usable energy as 41 kernels of corn or 600 grains of sorghum (milo).

So, for more intense waterfowl management within systems that foster multiple uses, it is best to create dedicated shallow wetlands that offer improved native aquatics and/or flooded dryland crops.

Impoundment with blind, showing drain.

I have had great success with flooding dryland grain crops for waterfowl in several different regions utilizing the impoundment system. Impoundments are not ponds or lakes designed for permanent water containment; their sole function is to flood a standing crop with 18-24 inches of water intermittently. They should not be confused with playa lakes, prairie potholes, or headwater mudflats. Basically, they are just level, fertile fields fully enclosed by low levees (24-36 inches high) pushed up and packed solid with a grader, scraper, compactor, or dozer. Small textured soils like deep clays, silty clay loams, or silt loams are best for these shallow excavations as they perc slowly. Impoundments can be built as one large single, several smaller ones in close proximity, or multiple units stepped down in a contiguous series (flood/drain one to another). Ideally, they should be 6 to 8-acre rectangles with a minimum of two acres. Over 10 acres in one field becomes too difficult to maintain an effective shooting range of passing birds.

The most important feature of an impoundment is the ability to flood or drain its contents at will. In southwest and more arid regions, the best sources of on-demand flooding are deep reservoirs that collect runoff year-round. The backside of these lake dams may be good choices, as they often represent Bottomland Range Sites that receive extra moisture and have a high available water capacity. These areas are often unused wasteland and can easily be converted to productive waterfowl habitat. Also, lakes on the inboard side of a dam can be siphoned to flood the lower impoundments easily and inexpensively. This allows continued watering of growing crops in summer and graduated control of crop flooding in fall. After season, the impoundment bottom is then drained and dried for next summer planting again. Water levels are regulated at the lowest point of a slight grade by simple standpipes and/or sluice boxes.

Dwarf grain sorghum (milo), Jap millet, short-season corn, soybeans, and rice are my choice of grain crops. For best results, grain plots should be weed-controlled, fertilized, and planted by June 1. Staggered plantings (5-7 days apart) of different maturity plants will provide more variety of seeds for a longer period. Jap millet can be planted all the way through July and still make seed by the November hunting season. Flooding begins after initial grain ripening and coincides with bird arrivals in the fall.

Mixed bag of divers and puddle ducks feeding in impoundment.

When hunting migratory waterfowl, the impoundment crop cannot be manipulated (shredded, disked, or intentionally knocked down). It must remain in its normal growth state until naturally depleted or reduced. Nearby, designated sanctuary ponds/lakes should be strictly enforced and their cover habitat protected.

Hunting blinds should be strategically placed with consideration to wind direction and sunlight early enough for camo-cover to blend in with surrounding vegetation.

As with any wild game, controlling the feedbag is the only positive way to ensure predictability of visitation within a short window of hunting opportunity. Whether you culture native aquatics or plant grain impoundments (or both), waterfowl harvest should be viewed as a completion of management efforts that can quickly become a passion!