Ducks Unlimited Challenges Delta on Predator Management

Editor’s Note: Ducks Unlimited recently challenged predator control as a management tool, first on its website and later in the November-December issue of its magazine. It is DU’s contention that habitat alone is the key to sustaining healthy duck populations and that predator-management programs are counterproductive to the long-term benefit of ducks and duck hunters.

Delta Waterfowl wholeheartedly agrees with DU on the importance of habitat, but disagrees that efforts to manage unnatural populations of predators are counterproductive. What follows is the text of DU’s frequently asked questions about predator management, along with Delta’s question-by-question response.

DU’s Answer: With a few important exceptions, waterfowl populations are doing extremely well. During the latter half of the 1990’s most duck and goose species were near record levels, and hunters in many areas experienced record-high harvests through the year 2000. Duck populations declined slightly in 2001 and 2002 due to dry conditions on the breeding grounds. In 2003, populations have rebounded, thanks to spring snow and rain in key areas of the breeding grounds where good nesting habitat still exists.

Q: Why did duck populations decline in 2001 and 2002?

DU’s Answer: Changes in duck populations are driven by a number of factors.

One of the most important is the amount of water present in prairie pothole wetlands on the breeding grounds. In 2001 and 2002 much of the continent’s duck factory was drier than normal and, consequently, duck numbers declined. Drought is part of the natural cycle on the prairies, where most of our ducks are produced. No one can make it rain on the prairies, so DU’s goal is to make sure that there will always be sufficient habitat for ducks when the drought cycle ends. Recent history has shown us that, when weather conditions are right, there is sufficient habitat to support “booms” in duck populations. For example, during the wet period of 1994–1999 duck numbers increased 69%.

Delta’s Response: Delta Waterfowl did not see the 31 percent decline in mallard numbers in 2000, 2001 and 2002 as “slight”, and we don’t believe hunters did either. Delta was concerned about the precipitous drop because—contrary to DU’s response—it began at a time when wetland conditions on the breeding grounds were still reasonably good.

What problem? “The single most important factor depressing current waterfowl populations is the low success rate of nesting hens that is a result of severe predation rates on the prairies. In many areas of Canada, this factor is thought to be even more significant than the historical loss of wetlands.”

The above statement is as true today as when it appeared in Ducks Unlimited Magazine in 1994. The quote was attributed to Dr. Bruce Batt, who at the time was with DU’s Institute for Wetland and Waterfowl Research (IWWR) and currently serves as DU’s Chief Biologist.

In a recently released study on mallards, Steven Hoekman reported that predation is a far more significant factor inhibiting population growth than wetland conditions.

Between 1993 and 2000—a time when the continental duck population was soaring thanks for a prolonged wet spell—DU’s IWWR conducted an exhaustive research project across prairie Canada. The final results of that nine-year study show that at 19 of 27 sites, the percentage of hens that died during the nesting season exceeded the number that successfully hatched a single duckling. Nest success for mallards exceeded the population-expanding minimum at only three of 27 sites (most scientists say 18 percent is the minimum maintenance level for mallards).

Question: What’s the most important thing we can do to help ensure healthy duck populations for the long term?

DU’s Answer: The most important thing we can do is to secure existing habitatand increase it wherever we have the opportunity. This is not just DU’s opinion. It is widely supported and practiced by the conservation community throughout the world. The most critical threat facing waterfowl is the continuing loss of important habitats. We lose more than 100,000 acres of wetlands and upland nesting habitat every year in the U.S. alone. That’s why DU’s singular focus is on conserving, restoring, and managing habitat for waterfowl.

Delta’s Response: Delta Waterfowl agrees on the importance of preserving habitat for the long-term benefit of ducks. But Delta believes waterfowl management can conserve habitat and actively manage for healthy duck populations.

Delta understands the importance of habitat, and has been fighting to protect habitats critical for duck production since its inception. It was Al Hochbaum, Delta’s first scientific director, who in the 1940s identified the importance of seasonal and temporary wetlands for nesting ducks—one of the most important discoveries in the history of waterfowl science.

When some of the best of those small wetlands were threatened by an action by South Dakota’s Natural Resources Conservation Service (NRCS) in the late 1990s, Delta was front-and-center in the fight to protect small wetlands. Delta also has been actively involved in the fight to save the wetland-protection provisions of the Clean Water Act.

Research conducted by Ron Reynolds of the US Fish and Wildlife Service showed that ducks achieve population-expanding nest success only where 40 percent of the landscape has grassy nesting cover. When large blocks of native prairie in North and South Dakota were threatened, Delta led the fight to save them.

But as much as Delta understands the importance of habitat, we also recognize its limitations. Putting 40 percent of the entire prairie pothole region into grass nesting cover is socially, politically and economically unrealistic. Where the landscape falls short of the 40 percent habitat threshold, other management tools are necessary.

Predator management and artificial nesting structures (Hen Houses) are two of those tools. Where habitat alone is not enough to impact duck production, Delta wants to put those tools to work raising more ducks.

Q: What about using predator control to produce more ducks?

DU’s Answer: On a local scale, predator control can provide immediate benefitsto a few waterfowl, but it will not contribute to the long-term security of waterfowl habitat and waterfowl populations or abundance on a continental or even regional scale. Nor is there a lasting impact on waterfowl numbers, because as predators are removed they are quickly replaced, or other predator populations increase. Predators have to be removed every year, and that is not a realistic option over large areas or over the long term.

Delta’s Response: It’s true predators must be removed annually, but it’s misleading to suggest that habitat conservation has a fixed cost. For example, refuge managers say controlling noxious weeds is more expensive than managing predators.

Some of the management tools endorsed by DU—electronic predator exclosures, nesting islands/ peninsulas and dense nesting cover—are extremely expensive compared to predator management, and also require annual maintenance. Predator exclosures and islands, for example, must be trapped annually to remove predators that took up residence during the winter months.

Predator management is relatively inexpensive, and science has demonstrated that controlling predators results in huge gains in nest success. Since Delta launched its predator management program in 1994, we have consistently increased nest success two- to three-fold. In the most recent nesting season, one of our predator sites had 80 percent nest success, which means 80 percent of all the duck nests in a 36-square-mile block were successful.

Before the population can increase, breeding hens must be successful. Nest success has been extremely high on Delta’s predator blocks, and we have the science to prove it.

Q: Why doesn’t DU use predator control in addition to habitat conservation?

DU’s Answer: Predator control is not a responsible use of our supporters’ contributions. The best scientific research shows that killing predators cannot result in meaningful increases in duck numbers or birds in the bag. It also threatens to undermine the broad coalition of public support on which modern waterfowl conservation depends. Dollars diverted into killing predators are dollars lost to habitat conservation. And, nearly every dollar spent on habitat for waterfowl is matched from special funds, such as the North American Wetlands Conservation Fund, which is set aside for habitat work. Funds from other sources in the U.S. and Canada are also often available, resulting in many projects being able to leverage at least 3 or 4 dollars for every DU dollar. Dollars diverted to killing predators are not matched.

Delta’s Response: We’d contend that a disturbingly high percentage of the dollars spent on habitat conservation have been dollars diverted from duck production.

A closer look at North American Wetlands Conservation Act (NAWCA) expenditures shows that less than 9 percent of all the NAWCA dollars spent in the US were spent in the pothole states of North Dakota, South Dakota and Montana combined. In recent years those three states have produced over half the ducks originating in the PPR, which contributes 60 to 75 percent of the continent’s total ducks.

Delta recognizes the importance of wintering habitat, but most scientists agree low production—not a lack of wintering habitat—is the major factor inhibiting growth of the duck population.

There are, however, volumes of scientific evidence showing that predation on the prairie breeding grounds is inhibiting the growth of the duck population.

Q: Is Ducks Unlimited concerned about how the non-hunting public might view predator control?

DU’s Answer: Any wildlife management plan needs to consider how public opinion might affect its success. The majority of North Americans would seriously question the ethics of broad-scale predator control as a means to better hunting. Predator control kills fur-bearing animals during the spring and summer, when their pelts have no value and when the young furbearers are still dependent on their parents for survival. As a result, trapped adults are discarded and wasted and the young are abandoned to starve. Thus predator control for the purpose of raising more ducks is, unambiguously, an activity that plays directly into the hands of those who are anti-trapping or anti-hunting, and it could be used by anti-hunters to turn more people against hunting

Delta’s Response: For the record, DU does trap furbearers. According to an article in the fall 2003 issue of Cattails, the official publication of Minnesota Ducks Unlimited, DU hired dozens of trappers to remove beavers from wild rice lakes in Minnesota last spring.

Delta supports the use of trappers to restore degraded habits in Minnesota and elsewhere. We do not, however, understand DU’s objection to Delta using trapping to restore a semblance of natural balance on the breeding grounds.

Is DU saying trapping dam-building beavers is acceptable but trapping nest-destroying predators is not? Where does DU stand on trapping nutria and muskrats?

DU says trapping “plays directly into the hands of those who are anti-trapping or anti-hunting, and it could be used by anti-hunters to turn more people against hunting.”

Delta doesn’t believe sportsmen should allow the animal-rights and anti-hunting community—who contribute nothing to wildlife conservation—to dictate sound management policies.

At Delta Waterfowl, everything we do is based on whether it’s the right thing to do for ducks and duck hunters. Our actions are directed by sound scientific research

As for the general public, research conducted nationwide by Terry A. Messmer of Utah State University showed that 58.9 percent of survey respondents supported controlling skunks, raccoons and foxes to improve duck nest success, and another 21.2 percent said they were neutral. Only 12.9 percent of those polled opposed controlling predator numbers for the benefit of nesting ducks.

The argument that predators are being trapped when the young are still dependent on their parents is the same argument the anti-hunters used in Ontario when they successfully banned spring bear hunting several years ago. When those same anti-hunters tried to ban spring bear hunting in Manitoba, Delta led the fight to defeat them.

We think it’s time to set aside the rhetoric and emotional arguments, and let science chart the course of waterfowl management.

Q: The issue of predator control seems to be creating a divide within the waterfowl hunting and conservation community. This can’t be good for duck hunters or waterfowl.

DU’s Answer: That’s right. Over the past decade, a broad-based culture of conserving wetlands and other wildlife habitat has matured in North America, especially among sportsmen. This has resulted in huge gains for wildlife. DU and its multitude of private and public partners are successful today because waterfowl hunters and other conservationists work together for the good of the resource. Other citizens from across a wide spectrum of society support waterfowl conservation because of the many additional benefits provided by waterfowl habitat.

There is great strength in our diversity and collective numbers, but waterfowl conservation will fail without all of us pulling in the same direction.

Unfortunately, the promotion of lethal predator control is harming the future of waterfowl conservation by diverting resources away from habitat conservation, which is critical for sustaining waterfowl populations in the future.

Ducks Unlimited’s conservation vision is for viable waterfowl populations that support hunting and other uses forever. This is a daunting task, and it will only be achieved if all of our collective energies are successfully directed towards securing the habitats that will support the birds everywhere they live.

Delta’s Response: Delta sees a dialog between conservation organizations as healthy, not divisive. Delta has never opposed DU’s conservation efforts, nor have we ever raised this issue in a divisive way. On the other hand, we have been compelled to defend our research and management tools when they’ve been challenged, which is exactly what we have been forced to do here.

Delta doesn’t believe predator management and habitat restoration are mutually exclusive. We totally support DU, the Nature Conservancy, the Audubon Society and other organizations working to preserve critical habitats across the continent.

But Delta also believes duck hunters have a right to expect an increase in duck production in return for the hundreds of millions of dollars they contribute to waterfowl conservation.

Science has shown that two of the best tools for increasing waterfowl populations are predator management and artificial nest structures, like Delta’s Hen Houses. DU’s own IWWR Assessment confirmed the effectiveness of Hen Houses in 1998. According DU biologists, “…with the exception of nest structures, nest success was low in all habitats at all four Assessment sites.”

Q: Is Ducks Unlimited alone in its views on habitat conservation and predator control?

DU’s Answer: No. The wildlife management community at large agrees. For example, the Mississippi Flyway Council (composed of leaders of wildlife agencies from all states and provinces within the Mississippi Flyway) recently issued a statement against the practice of predator removal. In part, the statement read:

“The Mississippi Flyway Council (MFC) does not support the practice of predator removal as a viable management practice to improve waterfowl recruitment over the long term or over large geographic areas. The MFC believes that the highest conservation priorities for improving waterfowl recruitment are the landscape-scale wetland and grassland habitat restoration strategies advocated by the North American Waterfowl Management Plan. Maintaining waterfowl breeding habitat is the highest priority for the long-term welfare of populations in North America.”

In August of 2003, the Arkansas Wildlife Federation’s Duck Committee (a group of concerned duck hunters and community leaders) published a report called: Improving the quality of duck hunting in Arkansas. One of the committee’s conclusions: “It all starts with the nest and proper habitat. The AWF Duck Committee has found that the more productive prairie pothole habitat we have, the more ducks we will have make the fall flight. Predator management may be helpful in small areas but is not believed to be practical on a large scale.”

Delta’s Response: Let’s be honest, the Mississippi Flyway states weren’t even unanimous in their rejection of predator management: Arkansas and Louisiana sponsored Delta predator management sites this spring. No other flyway has adopted a position against predator management.

Supporters of predator management are everywhere. The US Fish and Wildlife Service is Delta’s willing partner in a number of predator management efforts on the breeding grounds. The North American Waterfowl Federation (a coalition of state waterfowl organizations) in 1999 endorsed predator management. Even the Audubon Society and the Nature Conservancy recognize the impact of predators and manage predators on their properties.

Predator management occurs even on DU-funded projects. One good example is Kellys Slough National Wildlife Refuge, a $4 million project in northeastern North Dakota. During the first three years Kellys Slough was in existence, nest draggers were unable to locate a single successful nest. Only when a trapper was contracted did Kellys Slough begin producing ducks.

According to a question-and-answer sheet distributed by DU Senior Communications Coordinator Eric Keszler, “Because this (Kellys Slough) is a relatively small area surrounded by mostly cropland, the Fish and Wildlife Service found it necessary to conduct predator control. DU supports that decision.”

That’s exactly what Delta has been saying for years. Most of the drift prairie of eastern North Dakota meets the DU-described criteria—small patches of nesting cover surrounded by large expanses of cropland. Most of prairie Canada falls into the same category. Fifty percent of the ducks nesting in North Dakota settle in the drift prairie, where—as was the case at Kellys Slough—they have little or no chance of being successful because 90 percent of the nests are destroyed by predators.

Waterfowl management will never have the financial resources (or the acceptance from agricultural communities) to restore even a portion of the nesting cover or wetlands lost to agriculture during the last 150 years. Predator management and nest structures are two effective tools to address low duck production on fragmented landscapes like the drift prairie.

Q: Scaup and pintail populations continue to decline. Could predator control help these species recover?

DU’s Answer: No, simply because their low numbers are not caused by predation. Biologists have reached a consensus that the pintail decline is mostly caused by changes in farming practices. In the prairies of the U.S. and Canada, farmers have greatly reduced fall tillage to control soil erosion, conserve moisture, and reduce fuel costs. The “stubble” that is left from the previous crop is actually attractive to pintails for nesting as it is structurally similar to the short-grass prairie that they favor. Pintails are the earliest nesting 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. Since they don’t re-nest as well as other ducks, most of the year’s production can be lost in just a few days each spring when farming begins. Predator control will clearly not solve this problem, but DU is working hard with farmers to incorporate more pintail-friendly farming practices (such as fall-seeded crops) into their crop rotations and converting 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 of a major factor that is controlling scaup numbers comes from the Midwest, where Mike Anteau and Dr. Alan Afton, from Louisiana State University, have discovered that scaup are now about 80 grams lighter when they leave the prairies on their way to the boreal forest to breed. This is likely caused by degraded wetland conditions that affect their food supply just when they need it most to store fat and other nutrients for nesting. Predation is not a factor, but DU is continuing to support research to more clearly identify the issues that are actually driving scaup populations.

Delta’s Response: If we could put the shoe on the other foot for a moment, DU’s habitat-conservation efforts of the last 70 years haven’t been able to break the freefall of scaup and pintail numbers either. Does that mean we should abandon habitat conservation? Certainly not.

Scaup and pintails face special challenges that only recently were uncovered by scientists. In fact, Delta was responsible for much of the research that identified those challenges, and now we’re following that science in an effort to overcome them.

For instance, Delta is working diligently for Alternate Land Use Services (ALUS), a CRP-like grassland program for Canada. We’ve also been actively involved in the battle to protect some of the best pintail habitat on the continent, the native prairie of the Missouri Coteau in North and South Dakota. And we’ve increased pintail nest success dramatically on our predator blocks.

The pintail is a classic example of how ducks can benefit from cooperation among agencies and organizations with different missions. At Delta, we don’t see our efforts as being in conflict with DU’s goals, but rather as complementing them for the benefit of ducks and duck hunters.