Green-winged teal are small ducks that are found across North America. They get their name from the bright green patches on their wings that are visible in flight. Green-winged teal have a diverse diet and feed on a variety of plant and animal foods. Their small size allows them to forage in shallow water and reach food sources that are inaccessible to larger ducks. In this article, we will explore the diet of green-winged teal ducks in depth.
Plant Foods
Green-winged teal consume a wide variety of plant foods including seeds, leaves, stems, and aquatic vegetation. These make up the bulk of their diet.
Seeds
Seeds form a major part of the green-winged teal diet. They often feed on the seeds of aquatic plants that grow in shallow wetlands. The small size of their bills allows them to delicately pluck seeds from muddy areas and the water surface. Some common seeds consumed include:
- Wild millet
- Bulrush
- Spikerush
- Bur-reed
- Smartweed
- Duckweed
- Pondweed
Seeds provide the ducks with carbohydrates and essential fats. The abundance of seeds in wetland habitats allows green-winged teal to easily find this food source.
Leaves and Stems
Green-winged teal also graze on the leaves, shoots, and stems of many wetland plants. Their wide bills let them clip off pieces of vegetation near the water’s surface. Some commonly eaten greenery includes:
- Cattails
- Bulrushes
- Bur-reeds
- Pickerelweed
- Arrowheads
- Saltmarsh grasses
These provide the ducks with carbohydrates and fiber. The green leaves and stems of aquatic plants also supply protein.
Aquatic Vegetation
In addition to land plants, green-winged teal consume aquatic vegetation that grows entirely underwater. Diving just below the surface allows them to reach submerged food sources. Some examples are:
- Wild celery
- Coontail
- Elodea
- Muskgrass
- Water milfoil
Underwater plants provide nutrients like phosphorus, potassium, and calcium that are important for ducks. Their vegetarian diet supplies the steady energy they need.
Animal Foods
While plants make up the majority of their food, green-winged teal ducks also consume animal prey to get protein, minerals, and vitamins. This includes small aquatic invertebrates.
Insect Larvae
One major animal food source is the larvae of aquatic insects. Green-winged teal will tip forward and forage along the bottom with their heads underwater to find larvae buried in the mud. Common larvae they feed on include:
- Midges
- Mayflies
- Caddisflies
- Dragonflies
These larvae provide essential amino acids needed to build the ducks’ muscles and tissues. The fatty acids also give them energy.
Mollusks
Green-winged teal will also eat small mollusks that live in freshwater habitats. They use their slender bills to pluck snails, clams, and mussels from the muddy bottom. The soft body parts get digested while the shells get expelled. Examples include:
- Pond snails
- Fingernail clams
- Pea clams
Mollusks provide protein and micronutrients like zinc, iron, copper, and manganese to the ducks.
Crustaceans
The ducks occasionally eat small aquatic crustaceans as well. They snap up tiny shrimp, seed shrimp, water fleas, and other microcrustaceans floating in the water or at the bottom. These contribute additional protein and minerals.
While not a major part, animal prey provides supplemental nutrition to the mostly vegetarian green-winged teal. This diversity helps them meet all their dietary needs.
Habitat and Feeding
Green-winged teal inhabit shallow wetlands and marshes across North America during the spring and summer breeding season. These habitats have nutrient-rich mud that supports abundant plant growth and aquatic invertebrates for them to feed on. Some prime habitats include:
- Prairie potholes
- Marshy lakes
- Slow-moving streams
- Riverside wetlands
- Coastal salt marshes
Green-winged teal use their slender bills to sift through the mud and vegetation to find food. They will also tip forward and stick their heads underwater to reach submerged plants and aquatic insects. Their diverse diet composed of seeds, shoots, larvae, and mollusks allow green-winged teal to thrive in these productive wetland ecosystems.
Dabbling to Reach Food
Green-winged teal are classified as dabbling ducks, meaning they feed mainly at the water’s surface or by tipping forward to feed underwater. Dabbling allows them to skim floating vegetation, pluck seeds, and snap up prey without fully diving below. Their legs set far back on their bodies are ideal for swimming, but make walking on land difficult. By dabbling in shallow water, green-winged teal can readily find food near the surface.
Nocturnal Feeding
Green-winged teal will often feed nocturnally as well as during the day. Their eyes are specially adapted to allow them to see well in low light. Under cover of darkness, they are able to access food sources with lower risk of predation. Green-winged teal may employ a range of feeding strategies to meet their nutritional needs.
Diet by Season
The diet of green-winged teal can shift over the course of the year as they migrate and inhabit different regions. The foods available also change with seasons.
Spring
In spring, green-winged teal stop to feed heavily on their breeding grounds in prairie potholes, marshes, and other wetlands. These areas offer an abundance of newly sprouted aquatic vegetation, seeds, and emerging insect larvae, which females need to acquire nutrients for egg laying. Pairs and groups dabble in shallows, tipping to eat underwater.
Summer
Through the summer, breeding adults continue eating emerging aquatic plants, seeds, and insects to meet energy needs. Females require extra protein while nurturing ducklings. Adults lead young to protected, vegetated areas with plentiful food. Ducklings start by eating protein-rich insects and graduate to vegetation as they grow.
Fall
In fall, green-winged teal start migrating south in September. They stop over at nutrient-rich wetlands along migration routes to build up fat reserves. Seeds, plant tubers, and aquatic invertebrates are consumed in large quantities before migrating.
Winter
On wintering grounds in the southern U.S. and Mexico, green-winged teal feed heavily on seeds of plants like millet, bulrush, pondweed, and duckweed. They also graze on green vegetation in warm climates. Protein from aquatic insects and mollusks remains important. Large evening roosts provide safety.
The seasonal habitats of green-winged teal provide diverse and changing food sources throughout the year. Their generalized diet allows them to thrive in many wetland types.
Adaptations for Feeding
Green-winged teal possess specialized physical and behavioral adaptations that assist their feeding strategies.
Bill Shape
Their small, narrow bills are adapted for reaching food in mud and vegetation. The bill tip has tiny comb-like projections called lamellae. These let them sieve small organisms and seeds from the water or substrate. Their slender bills allow them to pick tiny food items bigger ducks can’t grasp.
Vision
To find food subsurface, green-winged teal have excellent underwater vision. Their eyes are adapted to allow them to see well while diving and feeding with their heads submerged. This helps them catch aquatic insect larvae and other prey.
Feet and Legs
Their feet and legs are set far back on their bodies, providing more power and thrust for swimming while sacrificing walking ability. Strong webbed feet propel them as they tip forward to feed underwater. Their legs let them paddle and dabble in shallow water to find food near the surface.
Preening Oils
Green-winged teal preen oil secreted from a gland near their tails over their feathers. This waterproofs their plumage so they can dive underwater while feeding without getting soaked. The buoyancy keeps them from sinking too deep.
Specialized adaptations like these maximize green-winged teal’s ability to exploit their chosen food sources in wetland environments.
Conclusion
In summary, green-winged teal are well adapted to take advantage of the abundant food sources offered in shallow wetland habitats. They consume a diverse mix of plants including seeds, leaves, stems, and aquatic vegetation which provide carbohydrates, fiber, and nutrients. Animal foods such as insect larvae, mollusks, and crustaceans supplement their diet with protein and fat. Their slender bills allow them to pick small food items from the water surface and buried in mud. Further adaptations like strong underwater vision aid their feeding abilities. Green-winged teal are able to thrive on a varied diet across North America’s wetlands.
