Waterfowl are birds that live in and around lakes, ponds and wetlands, such as ducks, geese and swans. Most eat grasses, aquatic plants, fish, insects, small amphibians and worms.

Ecologists have recorded several species in DuPage County. Resident waterfowl include the Canada goose (Branta canadensis), mallard (Anas platyrhynchos), American coot (Fulica americana), blue-winged teal (Anas discors), hooded merganser (Lophodytes cucullatus), pied-billed grebe (Podilymbus podiceps), ruddy duck (Oxyura jamaicensis) and wood duck (Aix sponsa). Migrants include the bufflehead (Bucephala albeola), canvasback (Aythya valisineria), common goldeneye (Bucephala clangula), green-winged teal (Anas crecca) and red-breasted merganser (Mergus serrator).

Canada Goose

(Branta canadensis)

There are two local subspecies of Canada geese: the more prevalent giant Canada goose, which breeds in DuPage and averages between 11 and 12 pounds, and the less-common interior Canada goose, an overwintering visitor that weighs between 7 and 9 pounds. These gray-brown birds are most distinguishable by their black heads and necks and prominent white cheek patterns. Flocks consist of families or groups of families, depending on the time of year. They fly in groups of up to several hundred often in V formations, which may cut wind resistance for the birds at the rear.

Geography and weather affect the onset of nest building, which often takes place on the ground near water, especially in low-lying, flood-prone areas, but also occurs on elevated sites on rocky ledges, above muskrat mounds or lodges, or in trees. Canada geese mate for life and usually arrive at their breeding grounds as mated pairs, but courtship and fighting between the males, or “ganders,” still occurs. To repel an adversary, a gander approaches with his neck held horizontally and bill opened while uttering hissing sounds. Once the standoff is over, the victorious gander returns to the female. In DuPage County, females lay an average of five to seven creamy white eggs, which hatch in May. The young leave the nest within 24 hours and usually fly within 70 days.

From late June to late July, Canada geese lose their flight feathers and their ability to fly. They can be aggressive during this time if they feel that their nests or their young are threatened.


(Anas platyrhynchos)

Mallards usually migrate south during the winter looking for open water, but during mild Chicago winters they may stay year-round.

Mallards are seasonally monogamous, which means they switch mates each year. The females, which may return to successful nesting sites, are responsible for raising the young and usually produce one brood a year. Prior to laying her eggs, the female will increase her weight so she can incubate the eggs. She lays an average of seven to 10 eggs and incubates them for about 23 days. The male leaves after the first week of incubation to join the male flocks. After the last egg hatches, the female takes her young to water within 24 hours, a trip that can be up to 1 mile long. The young are able to fly within 42 to 60 days.

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