—By Michael G. Anderson, Ph.D.
It's early June in southern Manitoba. Fresh green shoots of cattail and bulrush have joined the dried tan stalks of winter, offering the marsh a promise of renewal. The fields, grasslands, and trees will soon share the moist, hazy, deep-green look of early summer. It's a good time for new ducklings to greet the world.
In a patch of snowberry on a knoll of native prairie a mallard hen quietly calls to pipping eggs. On a floating nest, well hidden in a tiny cattail slough, a canvasback hen shifts around as her first two ducklings shed their shells and begin to dry in a patch of morning sun. These new waterfowl will face many challenges, each in their own way, before their first trip around the sun is complete.
For the young mallards, hatched with a remnant yolk sac to see them through their early hours, the first order of business is to shed their shells, dry off, and then follow "mom" to a suitable wetland where they can feed, hide, and grow. Mallards may nest a mile from water or on the edge of a pond. This hen is typical, having selected a well-concealed brushy spot about 50 yards from a wet swale, leading to a promising brood pond about 100 yards farther on. The brood will wait until dark to begin their trek, away from the eyes of soaring hawks and ravens.
The canvasbacks, meanwhile, are perched on a platform of dried cattails that looks like a bargain-basement muskrat lodge. There they will shed their shells, preen, and mostly keep warm as they nestle under their brooding hen through the afternoon and cool night ahead. Tomorrow will be soon enough to meet the water. Curiously, the first two ducklings to dry off are a little lighter and brighter yellow than their brood mates; they are redheads that hatched from eggs deposited by nest intruders four weeks ago.
For the mallard hen, it's time to find water. Calling quietly, she leads her new brood through the grass and down toward the swale. When you're barely three inches tall, stones, brush, and even bent prairie grass form an obstacle course. Many ducklings are lost to avian or terrestrial predators, such as hawks and foxes, during overland moves, especially when they are very young. Yet, hens can sometimes relocate broods over long distances safely. Moves of more than a mile by individually marked hens have been reported.
Diver hens and their broods move too. For canvasbacks, it's common for hens to choose small isolated ponds for nesting that are not optimal habitat for brood rearing, so a move along a chain of wetlands or even across a wheat field is not rare during the ducklings' first week of life. Later moves, for example at five to six weeks of age, happen too, most often when smaller ponds begin to dry up or ducklings need to add different foods to their diet.
The other common hazard for ducklings is cold, wet weather when they are small and unable to feed efficiently or keep their thin down covering waterproof. Though hens try to shelter their young under such circumstances, it is easy for ducklings to become dangerously chilled during a stretch of nasty weather. There is danger in wetlands too. Here in the northern potholes, it's mainly mink or a stealthy heron. Elsewhere, gulls, pike, and snapping turtles like ducklings as well.
During the next eight weeks for the mallards, and nine weeks for the canvasbacks, the ducklings will follow an endless cycle of feeding, preening to keep dry, and resting. Their legs grow strong, developing the mature functions needed to move about, dive, and escape capture. Wing development is delayed until they are mostly grown, with just enough time left to practice and gain strength before fall migration.
The little mallards scoot about on the surface, gleaning insects and other invertebrates with their alert mother in close attendance. Mostly they feed near the interface of flooded cover and open water. Northern pintail and blue-winged teal broods typically seek even thicker cover. When a harrier swoops low, or any other threat appears, the hen calls, the ducklings rush toward her, and they all scurry into the nearest tall flooded vegetation.
The little divers spend their days much the same, though within a week the seven canvasbacks and two redheads in this brood have tried diving too. It's fun to watch them arch straight down and then pop back to the surface like a fishing bobber. By the time they are a month old their legs will be strong enough to keep them underwater for several seconds, long enough to exploit other aquatic prey. And unlike for mallards, escape "cover" becomes deep, open water where the hen and brood quickly head when danger approaches.
As the weeks wear on, hens begin to spend more and more time away from their broods. By the time the ducklings are half grown, canvasback hens may attend them only about half the time. Why? We think part of the reason is that hens can sometimes fuel up quicker on a different pond, where they can concentrate on feeding themselves, bathing, preening, and other maintenance behaviors without having to attend to their ducklings. Hens eventually abandon their broods entirely, at somewhat younger ages if the brood hatched later in the season. Back on their own, hens almost always head to larger, more stable wetlands with others of their kind to replace their flight feathers, feed, and survive about a month of flightlessness before readying for fall migration. As much as hens invest in their ducklings, their imperatives also include their own survival.
Without their mother hen, and with advancing age and independence, the cohesion of duck broods weakens. Before she leaves, the hen often will have moved the ducklings to a larger pond occupied by other broods, where ducklings begin to intermingle. Their first attempts at flying can be comical—like the Wright Brothers—short and low with a less-than-elegant landing. As they gain purchase of the air young ducks begin to move about the pothole country where they hatched—first to neighboring ponds, then perhaps to wetlands within a mile or two of "home." Usually they seek the company of others, and flocks of mostly young birds are common on larger wetlands in late August and early September.
Once they can fly, these young ducks seek food, safety, and companions. Mallards, joining ever-growing flocks on staging wetlands like Big Grass Marsh, get introduced to feeding on waste grain in farm fields by following more experienced adults. Some of the young canvasbacks have made it to Delta Marsh to join a few thousand more; others have drifted to Oak Lake, where beds of maturing sago pondweed beckon. Some brood mates may still be together as this shuffle to fall staging marshes plays out, but some have no natal companions at all.
From nesting to fall staging, ducks rely on a wide array of wetland types, from tiny prairie potholes to big marshes and everything in between. Conservation of all these habitats is vital to the lives of these birds. By October they will all be heading south, following others who know the way, learning about the traditional foods, safe havens, and ways of their species. Yet each bird you see is writing its own unique story of survival, migration, and life.
Dr. Mike Anderson is emeritus scientist with Ducks Unlimited Canada and a freelance writer based in Winnipeg, Manitoba.