Ducks are often associated with freshwater ponds and lakes, leading many to wonder if they also inhabit the ocean or saltwater. While many duck species thrive in freshwater, some are uniquely adapted to marine life. The presence of ducks in saltwater is a way of life for specific groups, showcasing remarkable biological adaptations.
Not All Ducks Are Alike
The term “duck” encompasses a wide variety of waterfowl, each with distinct preferences for habitat and feeding strategies. These birds are broadly categorized into dabbling ducks and diving ducks, a distinction that significantly influences where they live. Dabbling ducks, such as the mallard, typically feed by tipping their bodies forward to graze on vegetation and insects near the water’s surface in shallow areas. Their legs are positioned more centrally on their bodies, making it easier for them to walk on land.
In contrast, diving ducks are built for underwater foraging, propelling themselves with large, powerful feet situated further back on their bodies. This anatomical difference allows them to dive deep to find food, but it also makes walking on land more awkward. While most ducks are indeed found in freshwater, this difference in foraging methods helps understand which types can exist in saline conditions.
The Sea Ducks
A specialized group, “sea ducks,” directly answers whether ducks live in the ocean. This tribe, Mergini, includes species spending much of their lives in or near coastal waters. Examples of these marine-adapted ducks include eiders, scoters, mergansers, goldeneyes, harlequin ducks, and long-tailed ducks.
These sea ducks are distinct from their freshwater relatives, exhibiting characteristics suited for their marine habitats. They are found in coastal bays, estuaries, and the open ocean, particularly during winter. Of 22 global sea duck species, about 15 are in North America, mostly in far northern latitudes.
Adapting to Saltwater Life
Sea ducks have physiological and physical adaptations to thrive in saltwater environments. A significant adaptation is specialized salt glands above their eyes. These glands function like filters, enabling the ducks to drink salty ocean water and excrete excess salt, maintaining their internal water balance.
Their plumage is dense and waterproof, providing insulation against cold ocean waters. A thick layer of down feathers beneath outer contour feathers traps air, insulating their bodies and increasing buoyancy. Furthermore, sea ducks have streamlined bodies and powerful rear-positioned legs, making them expert divers capable of reaching deep to forage. Some species, like the long-tailed duck, can reportedly dive up to 180 feet deep.
Where Sea Ducks Live and What They Eat
Sea ducks inhabit a range of marine environments, from rocky coasts and estuaries to open ocean waters. Many species breed in northern regions like the Arctic tundra and taiga, then migrate to coastal areas of the Atlantic and Pacific Oceans for winter. They form large flocks in these offshore environments during colder months.
Their diet consists of marine organisms, reflecting their diving capabilities. Eiders and scoters dive to the seafloor to consume mollusks and crustaceans. Mergansers, sometimes called “sawbills,” are fish-eating specialists with serrated bills designed to grip slippery fish. Other sea ducks may also consume small fish, marine invertebrates, and echinoderms, with their specific diet depending on available prey.