Ducks began migrating to the prairies countless generations ago to take advantage of abundant food and relatively few predators. Depending on habitat conditions and the size of the breeding population, half to four-fifths of the continental fall flight of ducks may come from the prairie “duck factory,” This includes approximately 70 percent of the mallards and pintails, 75 percent of the canvasbacks, 90 percent of redheads and blue- winged teal, as well as other species preferred by hunters. Prairie migrants visit all four flyways and are available to more hunters than ducks from any other part of the breeding grounds.

Historically, the “duck factory,” 80 percent of which is in Canada, had the potential to annually produce 50 million or more new ducks for the fall flight. However, two main factors stand in the way of sustainable high production. Natural droughts have always periodically diminished production, and for a century agriculture has transformed the prairie landscape, causing widespread, permanent loss and degradation of waterfowl habitat. Today the prairie likely has the capacity to produce fewer than half the ducks it could prior to the 1930s drought. The perennial debate among waterfowl managers revolves around how many ducks that is.

Not surprisingly, professional waterfowl management focused on the prairies as the best area to bolster natural production. However, management’s efforts have had only a minor impact on the size of the fall flight. Its efforts have been unable to counter drought and the devastating impact of modern agriculture. It has been unable to stop the decline or assist the recovery of several important species.

The pintail is the quintessential prairie duck, wonderfully adapted to cope with the dry reality of the prairies. Its anatomy, physiology, behaviour and social structure bespeak a duck that has evolved in grassland habitats. It is not a persistent re-nester and it tends to lay fewer eggs than the mallard, but female pintails have a remarkable reproductive capacity. When habitat conditions are good pintail populations can re-build quickly, potentially doubling in one breeding season. The big advantage pintails have over most other prairie ducks is their tendency to nest in very early spring, allowing the species to take advantage of temporary water and an abundant if short-lived food supply. In good years, young pintails are on the wing well before ponds dry up and food disappears in mid to late summer, frequently dooming the ducklings of later nesting species.

The pintail also is mobile, pioneering new habitats when the prairie is dry. However, pioneering females are rarely as successful as those on the wet prairie. Some females may not attempt to breed when they encounter drought-stricken prairies. In effect, they are “saving” themselves for a future breeding season, something they are able to do because they may live for 12 or more years. Presumably, this is an evolutionary strategy that allows pintails to wait out drought, which can last for years. Historically pintail abundance and those of other prairie ducks have tracked the wet and dry cycles of the prairie. Indeed, it’s worthwhile looking at prairie ducks in light of the characteristics that make the pintail so well-adapted to coping with drought.

Ducks in general have remarkably good reproductive potential. This is more true of dabblers than divers. Clutches of eight to a dozen eggs are common and some dabblers may re-nest if their eggs are destroyed. Mallards, for example, may make three or more attempts to produce a brood of ducklings Females do not re-nest if their eggs have hatched and their ducklings die. Survival of ducklings is enhanced by a female’s tendency to care for her young until they fledge. It is this robust reproductive potential that allows most species of ducks to be candidates for perennial harvest.

Living long enough to wait out droughts is an obvious requirement of prairie ducks. Wild ducks can potentially live for several years, particularly the larger species. This means that compared to the pintail, blue-winged teal have greater difficulty coping with drought. But even long-lived species have difficulty recovering from protracted drought, even among those ducks that have the ability to move in search of better breeding conditions.

Dabblers are more mobile than divers. Pintails, mallards and green–winged teal are very good pioneers. Pintails and teal may continue north to the adjacent aspen parklands, or even to habitats beyond this when they encounter a dry prairie. Mallards, the most adaptable duck on the continent, readily pioneer new breeding locations and habitat. They often establish permanent breeding populations where none previously existed.

Early nesting has served the pintail well, but it poses risks. Temporary water may encourage nesting, but it may not last long enough for the ducklings to fledge. Adverse weather like blizzards that occur after nesting has begun can have devastating effects on production. In some years, early nesters have tried and failed to reproduce, and thus are physiologically spent. Consequently they can’t take advantage of improved conditions later in the spring if this occurs. On the other hand, ducks that began nesting later may encounter improved conditions. Late nesters like blue-winged teal, shovelers, gadwall and widgeon sometimes enjoy greater success than pintails, even in dry years.

Dry conditions take their toll on ducks in different ways. Drought allows farmers to plough the edges of wetlands. Dabbling ducks and sometimes lesser scaup nest in the grassy margins of wetlands. Their nests in dry years are easy pickings for predators like foxes, skunks and racoons. Diving ducks typically fare better than dabblers because they nest over water in emergent vegetation like cattails or bulrushes, where, except for raccoons, their nests are less vulnerable to predation. Still, in dry years, even if there is enough water to rear ducklings, many nests are destroyed before hatching occurs.

Drought usually has its greater impact on ducklings, which depending on species take six to eight weeks to fledge. Divers, and dabblers like blue-wings and shovelers that utilize deeper wetlands, may fare better, but in drought years there is widespread duckling mortality of all species.

As I write this, reports coming out of the prairies in the spring of 2008 warn of widespread drought. Compounding the problem were late spring blizzards across much of the Canadian prairies key breeding locations. In Alberta, for example, temperatures at the end of April were below normal and snow a foot deep blanketed much of the province’s prime breeding area. While snow melt will help alleviate the dry conditions, a significant number of nests of early breeders will be lost.

Even if re-nesting occurs, females usually produce fewer eggs on their second or third attempt, and these eggs may be smaller than those of her original clutch. This results in less healthy ducklings with lower probability of survival. Ideally, early winter frosts seal the ground before a good snow cover builds up. Then a slow spring melt and warm spring rains fill the wetlands that are so critical to nesting and brood-rearing success. This hasn’t happened, with the result that we can look forward this autumn to a much small fall flight than last year.