Ducks readily consume duckweed, a small floating aquatic plant that forms a regular part of the diet for many aquatic fowl. Duckweed is a globally distributed freshwater plant found in ponds, lakes, and slow-moving water bodies. Ducks are drawn to this plant due to its constant availability and considerable nutritional density. This interaction is a common feature in freshwater ecosystems.
Understanding Duckweed
Duckweed is not a single species but a family of plants called Lemnaceae, including the genera Lemna, Spirodela, and Wolffia. These are among the smallest flowering plants on Earth, often consisting of a single, oval, leaf-like structure called a frond. They lack a true stem or distinct leaves and typically range from one to eight millimeters long, using small rootlets to absorb nutrients from the water column.
Duckweed is known for its explosive growth rate, allowing it to quickly cover the surface of a pond, forming a dense, green mat. It reproduces primarily through asexual budding, with some species able to double their biomass in less than 48 hours. The plant thrives in stagnant or slow-moving water rich in nutrients, such as nitrogen and phosphorus, often derived from agricultural runoff or animal waste.
Nutritional Value for Waterfowl
Ducks seek out duckweed because of its impressive nutritional profile, making it a high-quality forage. Duckweed is notable for its high protein content, which can range from 15% to over 40% of its dry weight, depending on the species and water nutrient levels. This protein level is comparable to or higher than that found in common feed supplements like soybean meal.
Duckweed provides essential amino acids, which waterfowl cannot produce themselves. It also contains various minerals, including calcium and phosphorus, and is a source of pigments like beta-carotene and lutein, beneficial for the birds’ health and plumage. The high digestibility of duckweed protein further contributes to its value as a natural supplement in a duck’s diet.
Ducks as Biological Control Agents
The consumption of duckweed by ducks leads many pond owners to consider using them as a natural method of vegetation management. Ducks will graze on the floating mats, but their effectiveness as a long-term control solution is often limited. The plant’s extremely rapid growth rate means that a small number of ducks usually cannot keep up with a heavy infestation.
Introducing a large number of ducks to a pond to control vegetation can inadvertently worsen the underlying nutrient problem. Duck feces are rich in nitrogen and phosphorus, the very nutrients that fuel duckweed’s prolific growth. This nutrient loading creates a cycle where the ducks eat the duckweed, but their waste immediately fertilizes the remaining plants, causing rapid regrowth.
Using ducks for control is most effective in small, balanced ecosystems where the duckweed has not yet formed a complete, thick mat. In cases of severe overgrowth, where the plant is shading out submerged aquatic life and contributing to low oxygen levels, physical removal or other methods are necessary. While ducks are natural consumers, they are seldom a standalone solution for significant duckweed problems.