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A duck with a metallic green head and bright yellow eyes paddles slowly about a shallow cattail marsh. It rides low in the water, skimming the surface with its tail. At first glance this mystery duck might be identified as a mallard. Then it raises its head and the unusually large spoon-shaped black (not yellow) bill is noticeable. The super-sized bill immediately identifies the duck as a northern shoveler, one of the dabbling puddle duck species to grace Wisconsin's wetlands in spring.
Its over-sized bill is not the only helpful clue that aids in northern shoveler identification. This is a duck with bright, colorful patches. The male shoveler has bright rufous flanks that contrast sharply and vividly with its snow white breast and white vertical patch just ahead of its black tail. His bold colors stand out prominently against a brown or green cattail background.
Mallards display similar colors, but in different locations on their bodies. The green-headed mallards have chestnut-colored breasts and lighter colored flanks in more subdued colors. The mallards seem to blend in more with their background. Mallards display similar colors, but in different locations on their bodies. The green-headed mallards have chestnut-colored breasts and lighter colored flanks in more subdued colors. The mallards seem to blend in more with their background.
Female northern shovelers and mallards are both dressed in shades of camouflage brown, but the female shoveler has that same over-sized bill which is brown washed in shades of orange.
The enormous bill is the most prominent feature of this 18-inch long shoveler. Early taxonomists also noticed it and dubbed the duck Anas clypeata, literally, duck with a shield. The large bill seems awkward for preening but makes the northern shoveler a very efficient feeder. Bills of all the surface-feeding ducks are lined with tiny, traverse tooth-like ridges or lamellae located just inside the cutting edge of both upper and lower mandibles. When the shoveler's bill is closed, these tiny teeth serve as a sieve. When feeding, water enters its bill and the duck presses its tongue against the roof of its mouth forcing water out the bill's backsides. The lamellae trap tiny food particles that are then swallowed.
These ducks can strain out incredibly small organisms such as plankton, diatoms and copepods which are unavailable to other surfacefeeding ducks. You may see one or a few shovelers paddling along the shore, often in single file, holding their bills on the surface while stirring up shallow water and organisms. Sometimes you will see these ducks swinging their bills from side to side straining food as they go. They will also dip their heads half underwater to feed on aquatic insects, seeds and submerged vegetation. These ducks rarely feed by tipping up as mallards frequently do, letting their curly tail feathers stick up in the air.
We mostly see northern shovelers during spring migration from late March into early May as they rest and feed before winging their way to preferred nesting areas in the prairie pothole region of the Great Plains and Canadian prairie provinces. During migration these quiet, retiring ducks might be found in shallow marshes, on flooded fields, small ponds, quiet bays and backwaters. Some northern shovelers do nest here on grassy meadows surrounding marshy wetlands. For 23 to 25 days the female sits tight on a well-hidden ground nest lined with down. She incubates an average clutch of 10-12 buff-colored eggs. Soon after hatching, the precocial youngsters follow their mother to the water. Even now, the ducklings display their proportionately large, spatulate bills.
Northern shovelers are just one of several duck species that make a visit to a wetland in spring so inspiring. Now is when all ducks are dressed in their finest and brightest nuptial plumage. The males are chasing away other males while courting the females. Meanwhile, red-winged blackbirds and marsh wrens are singing the joys of spring's warmth and northern leopard frogs are croaking their amorous come-ons. The natural world is coming alive and tuning up for warm weather once again.
Anita Carpenter warms up for spring observations near her Oshkosh home.