Quick Answer
Harlequin ducks primarily eat aquatic invertebrates and small crustaceans during winter months, often foraging in shallow waters with rocky substrates. They supplement their diet with some plant material. Their feeding habits are closely tied to the availability of food in their wintering habitats.
Foraging Strategies
Harlequin ducks are highly adaptable and opportunistic foragers, using a variety of techniques to exploit their winter food sources. In shallow waters, they use their sharp, dagger-like beaks to probe into crevices and under rocks, where they can find crustaceans such as amphipods, isopods, and small crabs. In areas with dense vegetation, they may also use their beaks to dig into the substrate in search of buried invertebrates.
Dietary Composition
Studies have shown that Harlequin ducks in winter feed on a wide range of invertebrates, including mollusks, echinoderms, and polychaete worms. In areas with rich marine life, such as estuaries and bays, they may also consume more abundant species like copepods and planktonic crustaceans. The specific composition of their diet can vary depending on the location and availability of food resources.
Feeding Patterns
Harlequin ducks typically forage in small groups, often in areas with abundant food and minimal competition. They have been observed to spend up to 70% of their daily time foraging, with the majority of this time spent in shallow waters. During periods of high tide, they may also feed on tidal flats and beaches, where they can exploit the newly exposed areas for food.
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