As duck seasons continue to limp along, more hunters are clamoring for a reduction in limits and/or season length. All under the guise that duck numbers will improve to levels of the “good ole days” if we dial back what we take. While a noble stance, the mindset hasn’t impacted any adjustment in the U.S. Fish & Wildlife Service’s season frameworks. The 2024-25 season will be the 28th in a row with a liberal framework and the 17th in a row allowing two mallard hens in a limit.
That begs the question: Are hunters overvaluing their impact on duck populations? Or is there a “flaw in the slaw” with the data the USFWS assembles to calculate harvest, and hunter impact is undervalued? With midcontinent mallard breeding population numbers at their lowest point since 1993, there are undoubtedly some factors at play that deserve consideration.
First and foremost, habitat on the Prairie Pothole Region is far-and-away the No. 1 factor driving the decline. Drought after drought has reduced the number of potholes ducks need to breed, coupled with dried-up potholes being converted to agricultural land and the loss of Conservation Reserve Program ground; suitable breeding habitat has been drastically reduced since the last wet spring. There is no denying that a dry PPR will never equal a notable population increase. Unfortunately, that is the era ducks have lived in for the past nine years, including another dry spring in 2024.
But while the hunting community waits for Mother Nature to do her thing, should we care about what we shoot and when we shoot it?
Duck hunters have been hearing “harvest doesn’t matter” for decades. Waterfowlers should not be naive enough to think this is precisely how waterfowl scientists intended hunters to interpret their impact on the population.
The reality is the statement “harvest doesn’t matter” is a very broad response to a highly complex topic. Harvest and waterfowl population dynamics are not that black and white. Like most wildlife, there is no ability to count every duck, dead or alive, which leads to uncertainty in managing the species.
Hunter-Harvest Debate
Population effects of hunter-harvest focus on two hypotheses: additive versus compensatory mortality. Waterfowl science defines compensatory as the same number of ducks killed by hunters that would have died anyway from predators, illness, weather, etc. — so that next year’s breeding population is unaffected by harvest. Additive is the converse of that, where the birds that hunters shoot are added to natural mortality so that next year’s breeding population is reduced lockstep based on how many birds were harvested.
North American waterfowl management ran off the additive mortality hypothesis, in which hunters impact populations, until the mid-1970s. New research around that time concluded that hunting didn’t have a notable impact, but subsequent seasons bounced all over the place, with length and limits. That changed when Adaptive Harvest Management was implemented in 1995.
Instead of knee-jerk reactions to short-term hurdles ducks experience, AHM compiles various data sources to set duck season frameworks. AHM has brought more consistency to season frameworks, as evidenced by our long run of liberal 60-day seasons.
With the breeding population at an AHM-era low point, there is a small but burgeoning rise within the waterfowl science community offering dissenting opinions on the impact of harvest on the midcontinent mallard population. A starting point for those raising questions begins with the quality of data. For instance, the breeding population count may be overestimating breeding pairs. During that survey, any drake observed in a group of less than five is counted as a breeding pair, whether seen with a hen or not.
The hunting community also raises a red flag, as hunter satisfaction has decreased to the point that not only has their success rate declined but also what they are seeing in the sky and afield.
That begs the question: Does hunter-harvest matter?
There is minimal disagreement that hunting has no real impact when duck populations are riding high — as in 8-10 million mallards, as that was the moving target goal of the no-longer-used North American Waterfowl Management Plan.
The conjecture is that when populations are this low, harvest is likely additive, and how could it not be?
According to retired Louisiana and Minnesota waterfowl biologist Dave Rave, a handful of assumptions tie hunting harvest to waterfowl populations: “Probably the biggest problem I see is that no research has ever indicated what sort of decrease in survival due to hunting would cause population effects. Because of that, no one can say how large or small a drop in survival due to hunting will cause a population effect.”
When populations have declined during liberal regulations, Rave states managers quickly note that no research shows hunting caused the downturn. Per Rave, “During the ‘stabilized regulations’ period in the 1970s and 1980s, scaup and pintails allowed a daily limit of 10 birds. Their populations declined dramatically during this period and have never recovered. Other duck species that nest in the same areas and habitat did not decline, so my conclusion would be that hunting harvest was at least partially responsible.”
High-Value Target
Rave also has concerns about the mallard hen harvest, which is calculated and extrapolated from banding data. According to Rave, “Some of the latest harvest data on mallards indicates that 7% of adult female mallards going into the fall are harvested, and another 2% are estimated killed from crippling. For young-of-the-year hens, it is even worse — 16% are harvested, and another 4% are crippled. So, 9% of all adults and 20% of all young hens are killed between the fall and before nesting due to hunting.”
Derived from the 2022 Mississippi and Central Flyway mallard harvest numbers and the reported sex ratios for each flyway, Rave calculated 346,358 hens were removed by hunters from the midcontinent mallard population in 2022. At the 2024 Mississippi Flyway Technical Committee meeting, respected Canadian Wildlife Service waterfowl research scientist Ray Alisauskas, using Lincoln estimates, believes there are roughly a million hens in the current breeding population.
Rave states regarding his calculation, “The 346,358 estimate is total hens, not just adults, but roughly one-third of the estimated total breeding population of 1 million hens. That hardly seems insignificant.” Rave isn’t stating hunters are harvesting a third of all mallard hens because juveniles are not included in the BPOP, but they are included in the total harvest. Those young hens are highly susceptible to shotguns, especially over spinning wing decoys in Prairie Canada and the Dakotas. Rave is firm; the number of hens harvested is far from inconsequential.
Waterfowl ecologist Todd Arnold of the University of Minnesota also shares concerns over the current mallard drake-to-hen ratios (see graph). “The AHM model for midcontinent mallards has assumed that 50-55% of the breeding population and fall flight is male, but population estimates based on Lincoln’s method suggest that 60-75% of the adult population is male, and that percentage has been increasing through time. Although every hen needs a drake to reproduce, she doesn’t need or want two or three of them,” says Arnold.
Mickey Heitmeyer, a native of Missouri and a member of the Arkansas Waterfowler Hall of Fame, expresses concern about the age of mallards harvested in Arkansas compared with the rest of the Mississippi flyway. Arkansas is killing much older birds, and younger hens are not making their way to southern states. They are either being harvested in Canada and northern flyway states or are stopping short. Either way, Heitmeyer fears that mallards with site fidelity to Arkansas may continue to decline once this cohort of older hens expires.
Hen ducks have it tough. According to banding data, more hen mallards die yearly from “natural causes” than from hunting. Per Rave, “But to be clear, this does not mean hunting has no effect. What we do know is that the only form of mortality that our waterfowl managers have any control over is hunting mortality.”
All Ducks Are Not Created Equal
Another consideration tied to hunter-harvest is that not all ducks, especially hens, are created equal, also known as heterogeneity in the wildlife sciences world. Heitmeyer coined the “super hens” moniker for highly productive hens. They will generate many offspring and/or breed more than once in the spring. On the flip side, some hens produce small clutches or none. The problem is that hunters don’t know if they’ve shot a valuable hen or a dud.
Duck production also is affected by the timing of when ducks are harvested. Shooting a hen during the last two or three weeks of duck season in Arkansas, when pair bonding is well underway if not complete, is likely far more detrimental than one shot in September over a spinning wing decoy in Prairie Canada. The hens that make it to late January deserve a chance to return north to be productive. These ducks are likely older and should be better at production.
Conservative Conservation
So next time someone professes “hunter harvest doesn’t matter,” or you think about pulling the trigger on that lone mallard hen floating through the decoys, thinking through the key points in this debate should at least cause a double-take, if not more. Hunters can’t control many things related to duck production, but they can control what they pull the trigger on each day afield.
With the mallard population in steep, short-term decline — a 48% nosedive since 2016 — something has to give while we wait on Mother Nature and a slowdown in the loss of prairie grasses on the proven Canadian breeding grounds and CRP in the Dakotas.
Hunter harvest does play a role in population management. At what level is the million-dollar question? With a degree of uncertainty in the datasets used to drive frameworks, waterfowl managers have their hands full trying to find the sweet spot between hunter opportunity and population increases. When the population experiences the current level of decline, brushing off hunter harvest as a complete nonfactor doesn’t feel right, especially regarding mallard hens.
With all that in mind, I would encourage duck hunters to take small, conservative steps to favor the ducks until things sort and settle. Be resource first. That sure sounds better than pushing them as hard as we can until USFWS says they can’t handle it anymore and a 30-day season is necessary. Or even worse.
