A primary purpose of Madduck is to present issues in a manner designed to stimulate meaningful discussion about the management of our flocks, and the equally important management of ourselves, the latter reflecting our dual (some say conflicting) role as both hunters and protectors of ducks. We believe strong public debate is necessary to expose past and present management failures so that we can make the modifications necessary to insure a bountiful future for both ducks and duck hunters.

Our success in sparking debate has exceeded our most optimistic expectations, judging from our increased readership, personal comments from concerned waterfowlers, internet discussions and so on.

Yet there are moments when we question whether a portion of our supposedly educated class is capable of carrying on meaningful debate. A case in point involves

a waterfowl biologist who recently in internet discussion arrogantly dismissed our analysis of the spinning-wing decoy kill as nothing more than “talking trash.” (See Back of the Envelope , Mar. 15, 2005.)

What are we to make of this? More importantly, who is talking trash?

Our analysis owed its derivation to a U.S. Fish and Wildlife Service summary of all “the available information on the effectiveness and use of electronic-motorized decoy devices for duck hunting.” It was distributed by Brian Millsap, chief of the Division of Migratory Bird Management.

The report made no estimate of the total duck kill that could be attributed to spinning-wing decoys. Instead, it summarized all SWD studies to date, saying:

• “The percentage of hunters using some form of these devices has increased steadily since 1999 (now exceeding 50 percent in many areas) in all states where studies have been conducted.”

• “In all cases … use of SWDs dramatically increased the harvest compared to periods when SWDs were not used.”

• “Overall, about 70 percent of all ducks harvested in these studies were taken while using SWDs, while approximately 30 percent were harvested when the SWDs were not in use.”

Our critic found no fault with these U.S. Fish and Wildlife Service findings. He did not challenge the data that suggest spinners account for 40 percent (70 percent minus 30 percent) of the SWD-related kill. Indeed, he estimated from personal experience that about 50 percent of decoy spreads he observed while hunting last season utilized spinners.

But he cavalierly derided as “talking trash” the next logical step – utilizing these data to estimate of the number of ducks killed over spinners.

Our calculation was based on the following premise: U.S. Fish and Wildlife Service harvest data for the 2003 season estimated American hunters killed 13.4 million ducks. The service’s spinning-wing decoy analysis found that in all studies the use of SWDs “dramatically increased the harvest.” Logic therefore tells us the kill of ducks attributable to SWDs lies somewhere along a continuum ranging from one to 13.4 million.

For our calculation we assumed, on the basis of the scientific studies, that half of all American hunters used spinners, these hunters killed half of all ducks and spinners accounted for 40 percent of their kill. Given a total kill of 13.4 million ducks, we concluded hunters with spinners killed 6.7 million ducks, and spinners accounted for 40 percent of this kill – a total of 2.7 million ducks.

We did not portray the 2.7 million as a precise estimate. Instead, we emphasized it was a “back-of-the-envelope” calculation, a ballpark estimate designed to quantify the spinner kill based on the best available scientific data in order to help each of us arrive at a decision on whether SWDs should be banned.

Nevertheless, our critic dismissed as trash “our calculations about the number of ducks killed by spinning-wing decoys.”

He argued any discussion of the spinner kill is meaningless because “we don’t even know how many hunters actually use them and how well they work in different locations as the season progresses.”

This statement is partly at odds with the U.S. Fish and Wildlife summary that concluded “over 50 percent of all hunters use them in many areas.” Indeed, who among us wherever we hunt has not noticed a proliferation of these devices? It also ignores the geographical distribution of the studies – two northern locations (Manitoba and Minnesota), two mid-latitude states (Missouri and Nebraska) and two wintering-ground states (California and Arkansas) that presumably would reflect the purported decreasing efficiency of the devices in mid and late season.

An equally important issue, which we did not address, is whether the spinner-kill increases the proportion of the fall flight killed each autumn (the so-called harvest rate), or whether it simply redistributes the kill from those without to those equipped with spinners, along with a shift in the traditional geographical distribution of the kill from southern states to northern states.

“This evaluation has not been done, and I’m not sure it’s possible without some regulations-based, flyway-wide experiment,” he stated. Moreover, he questioned whether such an experiment could isolate all the variables to provide an answer. “I don’t know how you would separate (quantify) the effect of spinners, framework extensions, three of the four warmest years on record, Hevi-shot, etc.”

Thus, by his own admission, he has no idea how many ducks are killed by the use of spinners, and furthermore has no idea how to find out.1

In a perfect world, his methodological criticism might have a degree of merit. But we do not live in an ideal world. We will never know the precise number of hunters who use spinners. We will never know precisely what portion of the kill is attributable to spinners and whether this increases or decreases the harvest rate. (The service noted that a preliminary assessment of a California mallard study suggested “an increase in direct recovery rates of locally-banded mallards concurrent with the use of SWDs,” but that “at present, no definitive conclusions have been reached.”)

The U.S. Fish and Wildlife Service further stated that efforts to further assess the impact of spinners is unlikely. “Costs to improve our population and harvest monitoring databases and to more accurately detect harvest-rate changes resulting from widespread usage of these devices would likely be prohibitive for management agencies, given current budgetary constraints.”

Our critic ignores the historical truth that waterfowl management decisions never have been based on unassailable mathematical analysis. Certainly, today’s SWD studies reflect a far higher degree of statistical rigor than Francis Uhler’s study of baited, live decoy pens along the Illinois River – a study that prompted authorities in the late 1930s to ban both live decoys and baiting. The SWD studies provide a higher degree of statistical rigor than the data used to justify the banning of electronic calls in the 1950s.

We further know that our data-based, back-of-the-envelope SWD-kill estimate – the best available estimate to date – exceeds the number of ducks raised annually on all national wildlife refuges, exceeds the number of additional ducks produced yearly on northern-prairie CRP lands, exceeds the number of ducks that once died each year from lead poisoning. This tells us the spinning-wing decoy kill is of sufficient magnitude to raise biological alarms.

So, who is the trash talker? A biologist who stands atop his self-proclaimed, know-nothing pedestal shouting to one and all that any debate is epistemologically bankrupt and therefore amounts to nothing more than “talking trash”? Or Madduck, which states its assumptions, reaches a conclusion based on the best available scientific evidence, places it into perspective, lets the reader decide for himself and encourages meaningful, wide-ranging debate in the belief that the issue is too important to ignore?

1 Madduck’s resident ethicist/conservationist Howard N. Ellman finds a key problem summed up in the clause "[he] has no way to find out . . ." The basic philosophical, practical, managerial issue is this: When (i) we confront a practice that we know enhances the lethality of every hunter, (ii) we know that populations are declining, (iii) we have no consensus as to why they are declining, (iv) we agree that it is probably impossible to isolate (and quantify) the impact of any particular hunting technique on populations as distinguished from a number of other factors, then what is the argument for preserving the right to use SWDs?

It comes down to libertarianism vs. conservative management. At some point, we know that libertarian concepts must have a limit in this field because human capacity for technological advancement is almost unlimited and our commercialism will assure expansion of each technological advance to the maximum extent of the market, unless limited by government regulation. We know that enough hunters will buy any device to facilitate kills to thus create that market. We also know that conservative management also must have a limit because the most conservative measure of all would be an outright ban that would not only hurt our traditions but could dramatically impact creation, enhancement and management of wetlands. So we strive for a balance here.

For me the answer is obvious, but I respect the concerns of men who instinctively rebel against expanding regulation. I come down in favor of regulation in this case because I can see no redeeming virtue in SWDs. Facilitating kills by non-traditional, technological means has no place in hunting, conservation, game management, you name it. Moreover, by interposing a technological device between the hunter and marsh craft required to succeed without that device nullifies the "social" or "cultural" value of the experience, to use Leopoldian terms. That to me is the crux of the debate. What is the reason for allowing use of these devices, particularly as we know that they must inevitably increase kill, at least to some degree? What is the reason for taking a risk of any sort to allow them?