Diving-duck hunting has always attracted a devoted following, particularly where they concentrate along their migratory routes and on their wintering grounds. Hunters rig for them on the big bodies of water they frequent, enjoying some of the most exciting waterfowling there is. Always the most numerous and widely distributed of diving ducks, lesser and greater scaup once were accessible to hunters throughout the four flyways. However, scaup have been declining since the 1970’s, alarmingly so during the last decade. The bluebill, once everyman’s diving duck, has fallen to levels where only the most dedicated hunters still pursue them. One such group involves layout boat shooters whose investment of money, time and energy must define them as scaup specialists. Not surprisingly, this hardcore has dwindled in number, mirroring the decline of the scaup.

Presumably it is traditions like layout shooting that Delta Waterfowl is trying to protect with its opposition to the U.S. Fish and Wildlife Service Regulation Committee’s recommendation to reduce the bag limit to one scaup per day. The question is: Is its opposition to lowering the bag limit a case of short-term gain that may well result in long-term pain?

Delta’s advocacy relies heavily on a panel of “scaup experts” which it convened to investigate the scaup decline. The consensus of this panel, which Delta describes as “some of the brightest minds in waterfowl management,” is that reducing the limit to one bird is wrong “given the current evidence.” Its primary criticism is that the service’s scaup population model is flawed, along with the data used in the model.

Specifically, the panel argues the model errs in three ways:

• The estimated rate of increase in scaup populations in recent years “may be low.”
• A better model would focus more on estimating the number of breeding females than the total population. (The panel acknowledges it is “uncertain how easy” this might be.)
• The service’s model “requires closer examination before it can be used for the basis to make harvest recommendations.”

This criticism is valid. What it overlooks is the likelihood of addressing the issues involved. The model is not inherently flawed, but modifications to make it a more effective predictor of population dynamics, and a more reliable tool for setting realistic hunting regulations, requires ‘fine tuning’ rather than wholesale change. Far more challenging is how to more effectively estimate growth rates and improve surveys of breeding females.

Delta’s acknowledgement that monitoring breeding females may not be easy is an understatement. Such monitoring can occur only on the breeding grounds – the prairie where lesser scaup predominantly breed and habitats farther north where greater scaup nest. Improving the survey would be logistically difficult and very expensive, and unlikely to happen without a major shift in waterfowl management’s priorities. It is difficult to believe that private organizations like Delta or Ducks Unlimited, or government agencies, will or even can do this. It is safe to say that this significant criticism of the model will not be addressed any time soon.

The panel’s concern that the model underestimates the rate of increase of scaup populations would require lengthy field research, and getting the quality of data required to satisfy critics would be daunting and unlikely to be accomplished anytime soon. These inadequacies mean that anyone using the current model as the basis for setting hunting regulations should be extremely cautious. Underestimates of population size and growth rates are preferable to overestimates. The weaknesses in the current model mean that using it as the basis for providing hunters with the maximum possible harvest is a risky objective and one that jeopardises the breeding stock.

Delta’s cautious and diplomatically worded criticism therefore offers nothing constructive. It suggests the group lacks the confidence to make a more definitive statement. The scientific community is well aware of the problems with the service’s model. One wonders how comfortable the panel members are when Delta refers to them as “scaup experts”. What exactly is a scaup expert and what would a scaup expert recommend to stabilize declining scaup populations? Delta’s concern that it would be difficult to increase the daily bag limit if warranted in the future is hardly an argument for opposing one-scaup bag limit now.

Can hunters take comfort in the assertion by Frank Rohwer, Delta’s scientific director, that “it’s highly unlikely that hunter harvest is a major factor in the scaup decline?” Leave the statistics and scientific mumbo jumbo aside for a moment and ask former Atlantic Flyway scaup hunters their opinion about what caused the decline in scaup. They point to the years when scaup were sacrificed as bonus or 10-point ducks to provide hunter opportunity and take pressure off other species. These hunters proved very efficient at killing daily limits of 10 bluebills. They confess that they knew killing 10 birds a day made no sense. Individual hunters were legally killing hundreds of scaup each season, far more than in previous years, as well as increasing the number of cripples. They describe a rapid decline in numbers of scaup that was obvious to everyone and that it happened surprisingly quickly. The shooting was great for about five years and then it was over. Scaup hunting went out in a blaze of glory. Today few Atlantic Flyway hunters specialize in scaup, which have become incidental in the bag. What were hunters and the U. S. Fish and Wildlife Service thinking back in the 1970s? Why did management fail to give scaup more relief from gunning pressure during the early 1980s when the prairie breeding grounds were ravaged by the deepest and most protracted drought since the 1930s? And the scaup decline has continued. It is difficult to believe that veteran hunters with years afield and biologists with their science could not have anticipated the current crisis.

Despite this history and other anecdotal evidence provided by credible sources, Rohwer stated that biologists who attended two recent scaup workshops “agreed that the cause of the population decline was likely caused by habitat changes, not hunting.” There is no question that habitat changes along the flyways have negatively impacted the capacity of scaup to reproduce as successfully as they did formerly. This is especially so for prairie breeding lesser scaup. But professional waterfowl management has only limited capacity to improve habitat conditions, either on the breeding or wintering grounds. In fact, habitat is likely to further deteriorate. Furthermore, management’s attempt to augment natural production has resulted in only modest success. Hunters almost certainly kill more ducks than management produces. The question is how do managers stabilize scaup populations without further curtailing hunting mortality?

Historically, waterfowl managers have been divided on the issue of the impact of hunting on duck populations. This often acrimonious debate has sometimes been fuelled by egos that were seemingly more important than safeguarding ducks and the hunting tradition. The camp that has held sway claims hunting has no additional impact on mortality within populations, and promotes maximizing hunter opportunity at seemingly any cost.

It seems ironic that the service has been forced to devise special harvest plans for species like black ducks, mallards, pintails, canvasbacks, redheads, and now scaup. These are ducks preferred by hunters. There are no similar harvest plans for shovelers, gadwalls, and other species that hunters do not favor. Special harvest plans are tacit acknowledgment that the gun plays a significant role in population dynamics, and a good many biologists believe manipulating the harvest through bag limits and season lengths is not only the most effective but the only realistic tool available to waterfowl management.

Increasingly, however, conservation-minded biologists who just as passionately support hunting, are recognizing the dual role that habitat and hunting plays in affecting duck populations. Habitat issues are undoubtedly the major culprit causing declines in ducks, but nobody can say that hunting is not contributing, especially when populations are diminished and in long term decline. Hunting can prevent or at least slow recovery of depressed populations. There is almost certainly a theoretical threshold below which a population has difficulty recovering. For most duck populations these thresholds remain a mystery, and this is the case for scaup. It would be reassuring if the Delta panel could say conclusively that hunting is not contributing to the decline of scaup or slowing its recovery.

In the 1960s H. Albert Hochbaum, the first director of the Delta Waterfowl Research Station, warned that in some years hunters killed too many ducks. He would tell students who had come to the station about the dangers of failing to better understanding population thresholds. I was one of his students and listened when he claimed that managers should recommend outright closures to protect some breeding stocks. He warned that for seriously depressed populations closure might have to be imposed for several years to boost populations above a critical threshold. His views about overly liberal bag limits and exceptionally long seasons were not popular with professional management. One might speculate that if he were alive today, he would admonish the service for not restricting the scaup harvest sooner. Scaup are not in any way endangered – quite the contrary. The issue is whether they can continue to sustain hunting pressure at current levels.

It is difficult for hunters to know whether to believe the service or Delta about the need to reduce the scaup limit. Faith is required because both claim to rely on the best available scientific evidence (which is derived from the same data). Waterfowl management is an imprecise science and hunters should be sceptical about whatever they are being told. They should let common sense guide them. How can it be in the best interest of scaup hunters to risk contributing to further decline and the future of their sport? In a sense, the one bird limit is a form of voluntary restraint, an idea Delta has promoted for years. Interestingly, this is tacit recognition that the gun can add to natural mortality.