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- Written by Clyde McMillan-Gamber Clyde McMillan-Gamber
Wood ducks and hooded merganser ducks are not closely related but have characteristics in common because they share nesting habitats near creeks and ponds in woodlands in much of the eastern United States.
Their shared niches molded them into being somewhat similar species (called convergence), particularly in their similar nesting behaviors. Both kinds of ducks adapted similarly to take advantage of woods and water habitats to their benefit.
Woody and hoody females hatch ducklings in tree cavities caused by wind ripping limbs off larger sycamore, silver maple, and ash-leafed maple trees along, or near, creeks and impoundments. There, clutches of eggs and newly hatched young are relatively safe, although some of each might fall prey to raccoons or barred owls.
Some people erect large nesting boxes near water in woods on their properties, so that these duck species have additional nesting places. And both kinds readily use them and increase their numbers.
During March, in woods and tree-lined cow pastures near water, I’ve seen pairs of woodies and hoodies flying from tree to tree and searching for deserted tree hollows. Both genders of each kind are lithe for agility when landing on tree limbs to rest or look around for a cavity.
But the duck species have to compete with each other, and raccoons and barred owls, to get a hollow. Some female ducks are not successful and spend the summer as bachelorettes.
Each female of both kinds lays about 12 eggs in a hollow and sets on them when the clutch is complete. That way, all the ducklings hatch the same day.
One day after hatching, each mother duck calls to her brood from water or the ground below. In response, ducklings of both species climb up the rough inside of the tree cavity to its entrance.
After a brief “look-around,” each fluffy baby, in turn, jumps from its nursery entrance and lands on water or a dead-leaf cover on the ground, bounces a bit, gets upright, and follows its mother to feed on aquatic invertebrates.
Those camouflaged ducklings exiting their tree-hole cradles are a fascinating sight to see.
Interestingly, some hens of both species lay some of their eggs in other hens’ nests, whether those nurseries are of their own species or the other one. The adopted ducklings hatch with their stepsiblings. All ducklings of both kinds instinctively feed on protein-rich aquatic invertebrates.
Adult wood ducks are omnivorous, eating plant material and invertebrates. But adult mergansers feed on small fish mostly, as well as tadpoles, crayfish, and aquatic invertebrates.
Female woodies and hoodies are mostly brown — good camouflage while raising ducklings. But drakes of both kinds have gaudy feathering to attract hens for mating. Drake mergansers even raise and lower white crests on their heads to attract attention.
Wood ducks and hooded mergansers are attractive, interesting ducks that raise young here in southeastern Pennsylvania. Seeing pairs of them in spring, or families of ducklings in summer, is a treat. They are lovely additions to the local avifauna.
Clyde McMillan-Gamber is a retired Lancaster County Parks naturalist.