The Hooded Merganser (Lophodytes cucullatus) is a small, distinctively crested duck species native to North America. The male’s prominent, fan-shaped hood gives the bird its common name and makes it easily recognizable on wooded ponds and rivers. This merganser is a specialized aquatic predator that relies heavily on capturing prey found underwater.
Primary Food Sources
The adult Hooded Merganser’s diet is dominated by aquatic animal life, making it a primarily piscivorous duck. Small fish constitute the most significant portion of its intake, often making up 44 to 81% of the diet depending on the environment. They commonly target smaller species like minnows, sunfish, and perch that are easier to consume whole.
Beyond fish, the merganser’s diet includes a substantial number of invertebrates. Crustaceans, particularly crayfish, are a favored, calorie-rich food source, sometimes accounting for up to 50% of the total food volume. They also consume aquatic insects, including larvae and beetles, mollusks, and tadpoles. Smaller prey items are preferred because they can be swallowed quickly underwater, minimizing the time the bird spends submerged.
How Hooded Mergansers Forage
Hooded Mergansers are specialized pursuit divers, actively chasing their prey underwater rather than filtering or grazing. They locate food primarily by sight, possessing eyes adapted for clear underwater vision. These ducks propel themselves powerfully through the water using their large, webbed feet, keeping their wings held tight against their bodies.
A key physical adaptation for securing slippery prey is the merganser’s slender bill, which features fine, saw-like serrations along its edges. These serrations, known as lamellae, function to provide a firm grip on fish or crayfish once they are caught. The prey is then maneuvered and swallowed headfirst while the bird is still submerged.
Seasonal Changes and Juvenile Diet
The composition of the Hooded Merganser’s diet shifts based on the availability of food throughout the year. During winter, when fish populations are less accessible due to ice cover or migration, the merganser relies more heavily on invertebrates. This results in a greater consumption of aquatic insects, crayfish, and other crustaceans.
The diet of newly hatched ducklings is distinctly different from that of the adults. Juvenile mergansers initially subsist almost entirely on small, soft-bodied aquatic invertebrates and insect larvae. These items are easier to catch and digest than fish, as the ducklings lack the strength and developed bill structure for handling larger prey.