Trumpeter Swans are the largest waterfowl species native to North America. These majestic birds, known for their snowy white plumage, can reach lengths of up to 5 feet 5 inches and possess wingspans that may extend nearly 10 feet. Understanding their dietary habits reveals how they sustain their large physique within their natural environments.
Core Food Sources
The diet of Trumpeter Swans consists almost entirely of plant material, which they primarily obtain from aquatic environments. They consume various parts of submerged and emergent vegetation, including stems, leaves, roots, and tubers. Their preferred aquatic plants include:
- Pondweeds (Potamogeton species)
- Sedges
- Rushes
- Arrowleaf
- Wild celery
- Bulrush
- Burreed
- Duckweed
- Wild rice
- Algae
- Chara spp.
- Elodea canadensis
- Horsetail (Equisetum)
- Lyngbye’s sedge (Carex lyngbyei)
While largely herbivorous, Trumpeter Swans may also consume small amounts of invertebrates, such as aquatic insects, mollusks, small fish, and fish eggs, which provide supplemental nutrients.
Dietary Changes Through the Year and Life Stages
The availability of food sources drives shifts in the Trumpeter Swan’s diet throughout the year. In colder months, when aquatic vegetation becomes less accessible or senescent, swans often rely more heavily on tubers and roots extracted from the muddy bottoms of water bodies. During winter, they might also forage in agricultural fields, consuming waste grains like corn and barley, or grazing on terrestrial grasses and even potatoes left after harvest. As spring arrives, new plant growth emerges, and swans shift their consumption to the fresh, tender shoots and foliage.
Young swans, known as cygnets, have different nutritional requirements in their early life stages. Immediately after hatching, cygnets typically consume a higher proportion of protein-rich aquatic invertebrates, including insects, small fish, fish eggs, and small crustaceans, which support their rapid growth. Over their first few months, as they mature, their diet gradually transitions to mirror that of adult swans, becoming predominantly plant-based. Parents often assist cygnets by stirring up the sediment with their feet, making submerged food items more accessible for the young to consume.
How Trumpeter Swans Find Their Food
Trumpeter Swans employ specific foraging behaviors to acquire their food, primarily in shallow wetland habitats. One common method is “tipping up,” where the swan up-ends its body, with its tail pointing skyward, to extend its long neck and reach submerged vegetation below the water’s surface. They use their strong bills to grasp and pull up plants, including their roots and tubers, from the muddy substrate. Their large feet can also be used to dislodge roots from the mud, creating currents that free the plant material.
These foraging techniques are well-suited to their preferred environments, which include large, shallow ponds, undisturbed lakes, pristine wetlands, and wide, slow-moving rivers. They also utilize marshes and estuaries, where abundant aquatic vegetation thrives. Additionally, in areas with human activity, swans may graze on emergent plants along shorelines or forage in flooded agricultural fields, adapting their feeding strategies to available resources.