Creature Feature

Gadwalls on the Canal

By Wayne Bierbaum

While taking a recent bike ride on the Chesapeake & Ohio Canal towpath, I saw many ducks and geese in the canal. Because they see so many people pass by, the birds were calm enough to be observed up close. They all seemed to be enjoying the duckweed that had collected on the up-wind water’s surface. I could hear the geese slurping up the tiny green plants, while mallard ducks were making smacking sounds as they were feeding. 

At the edge of a gaggle of geese were two small ducks that were quietly skimming up the duckweed. Although they initially looked like mallards they turned out to be a pair of ducks that I have rarely seen called gadwalls.

Gadwalls are smaller than a mallard and inhabit many of the same ponds and lakes. They are dabbling ducks like the mallard, meaning they are surface feeders and rarely, if ever, dive under water. Unlike mallards, gadwalls are monogamous. Finding their partners before the end of their first spring, they will then spend the rest of their lives together.

There are several other differences between the two species. Gadwalls migrate farther and frequently end up in Central and South America. Also, they spend more time in open water and when the young hatch, the mother will take them away from the shore and into open water. Mallards tend to prefer to stay near the shore.

Gadwalls like mallards are omnivores, eating insects, fish, amphibians but mostly plant material. Cornell Ornithology describes the gadwalls as a species that prefers eating the stems of underwater plants rather than the leaves.

Gadwall hens look like mallard hens but the gadwall drake (males) has a very complex finely detailed pattern in the gray feathers of its chest and sides. It looks like a pen and ink sketch. To add ornamentation, several loose light brown feathers drape down from its back. They also have a black tail end and dark eyebrows.

Gadwall ducks are listed as being common but they are generally skittish and hard to approach. On previous encounters, the few that I have seen were beyond 50 yards away. They can be found at Blackwater National Wildlife Refuge and along the Potomac River.  There may be some still hanging out along the C&O Canal.