By Jim Ringelman, Ph.D.
It’s tough to wrap your mind around some things. Like the size of the national debt or the number of humans inhabiting planet earth. I throw the Prairie Pothole Region (PPR) into this same mix of imponderables. More than 300,000 square miles in size, millions of wetlands, and tens of millions of breeding ducks. It seems impossible that the hand of mankind could cause much change in such a vast landscape. But we have. And we’re threatening to do more damage in the next decade than in any time in recent history. What could be the effect on duck populations and duck hunting? Intriguing new analyses provide a troubling answer.
Recently, researchers compiled data from many sources to address the question “What causes the mid-continent mallard population to change?” The answer reaffirmed what many biologists have long suspected: Events that occur during the breeding season account for 84 percent of the variability in the mallard population growth rate (Figure 1). Surprisingly, deaths that occur during the nonbreeding season—including that from hunting—accounted for just 9 percent of the change in the population growth rate. And because mallard population ecology is similar to that of many other upland-nesting dabbling ducks, we now believe that mid-continent populations of these other species are regulated by the same set of factors—nesting success, hen success, and duckling and hen survival during the breeding season. This finding has big implications for duck hunters.
Of the top 10 harvested duck species, six of them achieve their highest nesting densities in the PPR, and two more split their breeding range between the prairies and forested habitats. Collectively, these eight species made up nearly 80 percent of the U.S. harvest in 2002-2003. Clearly, if you’re a duck hunter, the chances are good that the PPR is supplying you with many, if not most, of the birds on your duck strap. The science is unequivocal, and it all points to the importance of the prairies. This is where Ducks Unlimited began its work 67 years ago, and where DU is focusing its resources in its efforts to save this imperiled ecosystem.