Habitat and weather control duck numbers
Prairie ducks showed a solid increase in numbers in 2003 after two years of decline caused by dry conditions—an identical pattern to what waterfowl enthusiasts have seen since the first settlers arrived on the continent. Most prairie duck species are near or above North American Waterfowl Management Plan goals. This outcome clearly shows that when the prairies are wet and good nesting habitat is available, ducks respond. And they do so without predator control. Even the promoters of predator control agree that when habitat conditions are good, reproduction by prairie ducks overwhelms predation, and we have excellent fall flights of ducks.
During periods of drought, DU's job is to make sure that when moisture returns there will be sufficient wetland and upland habitat for ducks to rebound yet again.
Scaup, pintails, and predator control
Despite the great duck populations of the last few years, scaup and pintails have continued to decline. Could predator control help reverse these problems? The answer is no—simply because low numbers of pintails and scaup are not caused by predation. Biologists have reached a consensus that the pintail decline is mostly caused by changed farming practices. In the prairies of the U.S. and Canada, farmers have greatly reduced fall tillage to reduce soil erosion and fuel costs and to conserve moisture. The stubble that is left from the previous crop is actually attractive to pintails for nesting the following spring, as it is structurally similar to the short-grass prairie that they favor. Pintails are the earliest-nesting duck species and, in some years, hundreds of thousands of hens establish nests in the stubble only to have farm machinery destroy them when spring planting begins. Because they don't renest as well as other ducks, most of the year's potential production will be lost in just a few days each spring when farming starts. Predator control will clearly not solve this problem. But DU is working hard with farmers to incorporate more pintail-friendly farming practices into their crop rotations, such as fall-seeded crops, and to convert marginal cultivated ground back into permanent grassland.
Most scaup nest in the boreal forest of western Canada and Alaska. This is the largest ecosystem in the world and covers millions of square miles where scaup are dispersed widely and where predator control is simply not a feasible alternative. The most recent evidence on a major factor that is controlling scaup numbers comes from the Midwest where Mike Anteau and leading waterfowl researcher Dr. Alan Afton, from Louisiana State University, have discovered that scaup are now lighter in weight when they leave the prairies on their way to the boreal forest to breed. This is likely caused by degraded prairie wetland conditions, caused by a variety of factors, that affect their food supply just when they need it most to store fat and other nutrients for nesting. Predation is not a major factor, but DU is continuing to support research to more clearly identify the issues that are actually affecting scaup populations.
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