Waterfowl are a diverse group of birds that spend their lives on the water, but they do not all share the same behaviors when finding food. Observing how a duck interacts with its aquatic environment provides the primary method of classifying its lifestyle. These differences in foraging techniques have driven distinct evolutionary paths, resulting in variations in physical form and daily activities.
Duck Feeding Strategies: Dabblers Versus Divers
The most significant distinction among ducks centers on how they obtain sustenance. One group, known as dabblers, employs “up-ending” or surface feeding, often in shallow marshes and ponds. These birds, including Mallards and Teals, tip their bodies forward, submerging only their head and neck to graze on vegetation or invertebrates while their rear section remains above the water. They exploit resources near the water’s edge and are not built for full submersion.
The other group, diving ducks, is built specifically for underwater pursuit, fully submerging their entire bodies when hunting. These birds actively propel themselves beneath the surface using powerful strokes to reach deeper water columns where prey resides. This group, which includes species like Canvasbacks and Scaup, is often found on large, open bodies of water where food is inaccessible from the surface. They require specialized physical modifications that distinguish them from surface-feeding relatives.
How to Identify Diving Ducks
Diving ducks possess several physical and behavioral traits that distinguish them from other ducks, even when resting on the water. They have a compact and streamlined body shape, which reduces drag during submerged movements. Their legs are positioned noticeably far back on their body, providing excellent leverage and propulsion for swimming underwater.
This rearward leg placement is highly effective for maneuvering in the water but results in an awkward gait on land. When viewed on the water, a diving duck rides lower and looks heavier than a surface-feeding duck, often submerging its body slightly to reduce buoyancy before a dive. They favor deeper, more expansive bodies of water, such as large lakes, reservoirs, or coastal bays, utilizing their diving ability.
The method of taking flight offers another difference. Because their wings are relatively smaller and their bodies are dense, diving ducks cannot spring vertically into the air like surface-feeding ducks. Instead, they must run, or “taxi,” across the water surface, flapping their wings rapidly to gain the necessary airspeed for lift-off. This running takeoff is a telltale sign that the bird is built for life beneath the waves.
Common Species That Dive Underwater
Several species across North America and the globe are known for their diving lifestyle. The Canvasback is one of the largest and most recognizable, noted for its distinct, long sloping forehead and bill profile that gives its head a wedge-like appearance. This species primarily feeds on the roots and tubers of aquatic plants, diving to pull them up from the bottom of deep lakes.
The Redhead is another common type, where the male is easily identified by its bright reddish-chestnut head and rounded profile, contrasting with the black chest and grayish body. Redheads forage in slightly shallower water than many other divers, consuming the seeds and leaves of aquatic plants along with insect larvae. They are sometimes confused with the larger Canvasback but lack the distinctive sloping face.
The Scaup includes both Greater and Lesser species and is frequently seen in large flocks on open water. They are nicknamed “bluebills” for the color of their beaks. The two Scaup species are nearly identical, but the Lesser Scaup tends to have a more domed head shape and is often observed in marshier, shallower habitats than the Greater Scaup.
Mergansers, such as the Common, Hooded, and Red-breasted species, are specialized divers. Unlike many other diving ducks that eat plants and mollusks, mergansers are piscivorous. To facilitate this diet, they possess a long, narrow bill with serrated edges, which functions to grip and secure slippery prey underwater. Some Merganser species, along with Long-tailed Ducks, are among the deepest divers, recorded foraging at depths of forty feet or more.