When spring unfolds, our woodland pond comes alive with ducks. Activity accelerates as the ice melts, creating open water for waterfowl pairs who have been waiting in the harbour. During the previous fall, some pairs arrived to explore the site for potential nesting. We watched their activities from our home overlooking the pond. The house became an observation blind.

In Eastern Canada, cavities in old trees are preferred nesting sites for five duck species. Our property is former farmland without mature trees. We built the pond in a drained marsh that had been converted to pasture. A natural outlet without a dam allows fish passage. We erected two nest boxes on yellow birches and red oaks we’d planted 20 years before along the pond’s edge. The site became attractive for common, red-breasted, and hooded mergansers (Lophodytes cucullatus), plus wood ducks. In New Brunswick, common goldeneyes also nest in old trees along the Saint John River (Wolostoq) and its tributaries.

Wood ducks and hooded mergansers checked out the nest boxes first. With males leading, wood duck nest box inspections began in late March. Hooded merganser hens then made their assessments.

This pond is about the length of an Olympic swimming pool. Muskrats, beavers, mallards, black ducks, and others were already eating its aquatic plants. Wood ducks prefer larger lakes, rivers, and streams with abundant, seed-bearing aquatic plants like smartweed and pickerelweed. Eventually, wood duck activity on our pond gave way to hooded mergansers. The “hoodies” are equipped with hooked saw bills and spiny tongues to catch fish in the pond, stream, and nearby harbour. In addition to fish, they consume some seeds and leaves, adult frogs and tadpoles, snails, other crustaceans, and insect larvae.

Small birds, male hooded mergansers are among the most beautiful ducks. Found only in North America, they nest beside forested streams, wetlands, and ponds from Alaska to Nova Scotia. Beaver ponds are a favourite breeding site. They are wary and secretive. Wintering occurs close to coasts on both sides of North America, south as far as Florida and Mexico, although recent climate change has some overwintering in Nova Scotia.

Drakes (males) flash white crests with black edging on their heads when facing a competitor or courting a female. Their flanks include rusty brown plumage and striking black and white bars. Courtship involves much head bobbing, splashing, and rearing up with bills pressed to chests. It takes time and competition to impress a female and become a mated pair.

Females sport lesser Elvis Presley head crests and more subdued, rusty dark heads, bills, and chests. Feather colouration is a rusty grey with a loose, tawny crest and dusky appearance. Being more camouflaged renders them less noticeable to predators like chain pickerel, snapping turtles, hawks, and raccoons. Both sexes have golden eyes.

Pairs seek a hole in a tree near water. Pileated woodpeckers excavate, use, and abandon such cavities. Mature cavity trees are scarce on our property, but nest boxes are an acceptable substitute, if sized and placed correctly.

As many as seven pairs at one time focused around the two nest boxes beside our pond, with males jousting for superior positions, chasing other drakes, raising their crests, and uttering long, frog-like croaks as they court, with much diving and even summersaulting.

Females stay apart while pair bonds are active. After egg laying, hens spend time together on the pond, taking turns incubating the eggs. Multiple females use each box, depositing up to 17 eggs.  

Incubation takes about 32 days. Within a day after hatching, with all the youngsters dry, the hen calls to them, enticing them to leave. The lightweight ducklings take a leap of faith, jumping out of the box to the ground below. They are highly active, curious, and playful. They quickly disappear downstream with the female to the shelter of the harbour, where they can find abundant food.

Erecting nest boxes near water makes a world of difference to cavity-nesting ducks. I clean out each box every fall to eliminate any overwintering parasites and install new wood chips to present fresh accommodations in the spring.

If you have a pond or there’s one nearby lacking old trees, consider installing a box. It could make a world of difference for hooded mergansers and other ducks.