By Thomas E. Moorman, Ph.D.
Judging by the title, you might assume that this column is about how to prepare a healthy duck dinner
for your family and friends. But, of course, that is wild game chef Scott Leysath's department. This column is about another type of duck salad—aquatic vegetation, on which many ducks thrive.
Waterfowl consume a host of aquatic plants
, including various species of pondweed, southern naiad, wild celery, wigeon grass, coontail, and milfoil. Some of these plants are totally submersed and complete their life cycle without ever breaking the water's surface. Others have floating leaves or flowers, and some have both. Most are native to North America, although a few species of introduced exotic plants such as Eurasian milfoil are also consumed by ducks. In total, these plants represent at least 25 plant families and are important food sources for several species of waterfowl.
Nearly all of North America's ducks eat aquatic plants, at least opportunistically, and many species consume a largely vegetarian diet throughout much of the year. Gadwalls
and American wigeon
relish the leafy portions of aquatic vegetation. Green-winged teal
, northern pintails
, and mallards
prefer the seeds produced by wetland plants. Canvasbacks
, and scaup
feed heavily on roots and tubers, while ring-necked ducks
consume more leafy plant material and seeds.
Given the diverse food preferences of North America's ducks, an important objective for waterfowl managers is to conserve wetlands that offer the birds a variety of aquatic plant foods. Growing a salad buffet for ducks begins with healthy wetlands and suitable growing conditions. Good water quality, an appropriate range of salinity in coastal areas, adequate sunlight penetration to the pond bottom, appropriate water depth and wetland soils, and limited wave or current energy are all required to promote the growth and development of dense stands of aquatic plants.
Such conditions are especially common in the coastal ponds of the Gulf of Mexico. By late summer, the surface of these shallow, fertile wetlands can be covered with aquatic vegetation so thick that it looks as if you could walk on it. These duck salad–rich habitats are heavily used by migrating and wintering waterfowl, starting with blue-winged teal, which begin arriving in August, followed in the fall by other puddle ducks such as pintails, gadwalls, wigeon, and green-winged teal. It is also not uncommon for waterfowl, coots, and gallinules to consume nearly the entire annual crop of desirable wetland plants in these ponds by mid- to late winter.