Ducks that eat fish are skilled and adaptable hunters, equipped with specialized behaviors that allow them to thrive in aquatic habitats. Unlike their plant-eating relatives, these ducks are more carnivorous, often diving beneath the water’s surface in search of prey. Their sharp eyes and quick reflexes make them efficient at spotting movement in the water, where they pursue small fish, crustaceans, and aquatic insects.
Physically, these ducks tend to have streamlined bodies and strong legs that make them powerful swimmers. Their bills are often narrow and serrated along the edges, helping them grip slippery fish. Some species dive deep, using their webbed feet for propulsion, while others prefer to chase fish near the surface. Their plumage is usually dense and oily, providing excellent waterproofing and insulation during repeated dives in cold water.
Their hunting technique is both graceful and strategic. They often dive silently, disappearing beneath the surface with barely a ripple, and emerge moments later with a wriggling catch in their bills. Some can stay submerged for surprisingly long periods, demonstrating impressive stamina and lung capacity. They may also work in pairs or small groups, taking advantage of schools of fish by driving them toward shallower waters for easier capture.
These fish-eating ducks typically inhabit lakes, rivers, coastal bays, and estuaries where prey is plentiful. They migrate seasonally, following the movement of fish populations and the availability of open water. Their presence in an area often reflects the health of local aquatic ecosystems, as they depend on clean, well-stocked waters to sustain their diet.
Ducks That Eat Fish
Common Merganser
Often called the “fish duck,” the Common Merganser is the quintessential fishing duck. The males are striking with dark green heads and bright white bodies, while females have a elegant rusty-orange head crest.
- How They Fish: They are pursuit divers. With their sleek bodies and powerful webbed feet, they can chase down fast-moving fish underwater.
- Special Adaptation: Their long, thin, serrated bills are perfect for gripping slippery fish. They often hunt in small flocks, herding fish together.
- Diet: Almost exclusively fish, including minnows, trout, salmon, and perch.
Red-breasted Merganser
A close relative of the Common Merganser, this duck is often found in saltwater or brackish habitats like coastlines and estuaries.
- How They Fish: Incredibly agile swimmers, they can make rapid, twisting turns underwater. They are known to form coordinated hunting lines to drive schools of small fish into shallow water.
- Special Adaptation: Like all mergansers, they have a sharp, serrated bill. They are among the fastest-flying ducks and remarkably fast swimmers.
- Diet: Small fish, crustaceans, and aquatic insects.
Hooded Merganser
The smallest of the three North American mergansers, the Hooded Merganser is known for the male’s magnificent white crest, which it can fan open or close.
- How They Fish: They are visual hunters. Their eyes are specially adapted to see clearly underwater, allowing them to spot prey. They dive in smaller, shallower bodies of water like wooded swamps and ponds.
- Special Adaptation: They have a third, transparent eyelid (a nictitating membrane) that acts like goggles to protect their eyes underwater.
- Diet: A mix of small fish, crayfish, and aquatic insects.
Smew
This small, elegant merganser is native to Europe and Asia. The male is a stunning vision in black and white, looking almost like a porcelain figurine.
- How They Fish: Like other mergansers, they are diving ducks that pursue small fish in freshwater lakes and slow-moving rivers.
- Special Adaptation: Their serrated bill is smaller and more delicate than their larger merganser cousins, perfect for catching the small fish they prefer.
- Diet: Primarily small fish, along with aquatic insects and crustaceans.
Common Goldeneye
Named for their brilliant yellow eyes, these ducks are compact, powerful divers. Males have a distinctive dark head with a white circular patch between the eye and bill.
- How They Fish: They forage by diving in open water, typically in medium depths. Their wings are held tight to their bodies, and they propel themselves with their feet.
- Special Adaptation: Their eyes remain highly functional underwater, allowing them to spot prey. They are also known for their rapid wingbeats in flight, which produce a loud whistling sound.
- Diet: While they eat a fair amount of aquatic insects, crustaceans, and mollusks, fish and fish eggs make up a significant part of their diet, especially in winter.
Bufflehead
These are small, feisty, black-and-white diving ducks. The male has a large, puffy head with a striking white patch that seems to cover most of it.
- How They Fish: Buffleheads are constant divers, disappearing underwater with a quick leap. They dive in shallow bays and estuaries.
- Special Adaptation: Despite their small size, they are tough and resilient divers. They have a high wing-loading, meaning they need to flap their wings very quickly to become airborne.
- Diet: Their diet is omnivorous, but they consume a substantial amount of small fish and fish eggs, along with insects and mollusks.
Long-tailed Duck (Oldsquaw)
A true sea duck of the Arctic, the Long-tailed Duck is famous for the male’s long, slender tail feathers and its complex, yodeling call. It is one of the deepest diving ducks in the world.
- How They Fish: They are champion divers, capable of reaching depths of over 200 feet (60 meters) to forage on the seafloor. They use their wings to “fly” underwater.
- Special Adaptation: Their body structure is built for deep dives, with heavy bones and powerful pectoral muscles. They spend more time underwater than on the surface.
- Diet: While they primarily eat mollusks, crustaceans, and other invertebrates, they will also take small fish and fish eggs when available, especially during the winter months in marine environments.
Greater Scaup
Often seen in large, sprawling “rafts” on coastal bays and lakes, the Greater Scaup is a sturdy diving duck. The male has a dark head with a green iridescent sheen (which can look black at a distance) and a light gray back.
- How They Fish: They are classic diving ducks, propelling themselves with their feet to forage on the bottom in water typically up to 20 feet deep. They are often found in large flocks that dive and surface in unison.
- Special Adaptation: Their broad, blue-gray bill is well-suited for crushing the shells of mollusks, but it is also effective for capturing smaller prey. They are highly social foragers.
- Diet: While their primary diet consists of mollusks, crustaceans, and aquatic plants, they actively consume small fish and fish eggs, especially during the winter and migration periods.
Black Scoter
A true sea duck of rugged coastlines, the Black Scoter is almost entirely marine outside of the breeding season. The male is jet black with a distinctive bright yellow knob on its bill.
- How They Fish: They are pursuit divers, using their wings and feet to swim underwater, often in turbulent, wave-swept environments where they forage along the seafloor.
- Special Adaptation: They are built for tough conditions, with a robust body and a strong bill for prying and capturing prey. Their vocalizations include a plaintive, melodic whistle that is a classic sound of northern seas.
- Diet: Their diet is varied but heavily reliant on animal matter. While they focus on mollusks, crustaceans, and marine worms, they will readily catch and eat small fish and fish eggs when the opportunity arises.
White-winged Scoter
The largest and bulkiest of the scoters, this duck is easily identified by the white speculum (patch) on its wing, visible in flight. Males are solid black with a similar, but more muted, colorful bill patch.
- How They Fish: Like the Black Scoter, they are powerful divers in marine habitats, though they also use large inland lakes. They can handle deeper water and stronger currents than many other ducks.
- Special Adaptation: Their large, sturdy bills have a unique structure that helps them crush hard-shelled prey, but this strength also allows them to subdue small fish. They are known for forming long, straggly lines when flying low over the water.
- Diet: Mollusks like mussels and clams are a staple. However, fish—particularly small bottom-dwelling species—and fish eggs are a consistent and important part of their carnivorous diet.