Are biologists counting ducks that aren't there? Maybe

Aldo Leopold said early last century that few species were as difficult to manage as ducks.

Resident game such as deer can pose challenges to regulate, he said, but generally their bounty isn't shared among residents of different states. Ducks, on the other hand, whose migratory routes can take them from the Arctic to South America, passing over, and landing on, many states — and hunters — are the penultimate shared resource.

Which explains why, ever since passage of the Migratory Bird Treaty Act (MBTA) in 1918, opinions have varied widely about duck management, and particularly about division of the resource.

Before passage of the MBTA and other similar treaties, market hunters fought tooth and nail to keep their punt guns booming on flocks of what literally were sitting ducks. Money aplenty could be made selling these fowl to big city restaurants, and rail cars loaded with ice-packed mallards, canvasbacks and other feathered fare regularly delivered the goods to waiting customers.

Another, more recent example of a duck-management controversy arose in the 1970s, when waterfowl managers from Louisiana and other southern states complained Minnesota was killing too many ducks. Minnesota had so many hunters, the argument went, that in fall the state in effect erected an "iron curtain" that prevented large numbers of these birds from escaping the state alive.

Not to be outdone, Minnesota waterfowl managers countered that their southern counterparts abided too much illegal hunting, and as a result the number of ducks thought to be poached in the southern Mississippi Flyway rivaled the number killed legally.

These and many other duck-management hullabaloos notwithstanding, certain challenges confronting waterfowl leaders today are unique.

First and least controversial is the falloff in recent years of duck-hunter numbers. Minnesota, for example, had 96,000 duck hunters as recently as 1999, and only 55,000 in 2020. In the same span, Louisiana, which throughout recorded history has been ground zero for waterfowling, went from 86,000 duck hunters to 38,000.

One reason for the decline is that older waterfowlers are graying out and quitting the sport. But fewer ducks are also a reason why many hunters say they have hung up their guns — this even though, as recently as 2015, the U.S. Fish and Wildlife Service reported North American ducks were at "record high" population levels.

This disparity — between what many hunters see in the field and the estimated size of the continental duck population, based on biologists' spring counts — is at the heart of a growing distrust among some hunters with duck managers' abilities to calculate the size of the resource.

In 2015, for example — the year of "record" duck numbers — Minnesota waterfowlers killed 573,000 ducks, down from 831,000 in 1999 (albeit the state's per-hunter daily duck harvest rose in 2015 to 1.57 from 1.31 in 1999, due to fewer hunters being in the field in 2015). Also in 2015, Louisiana hunters killed 846,000 ducks, down from 1.9 million in 1999.

Consider still another controversy: duck seasons and limits.

Established by the U.S. Fish and Wildlife Service (USFWS), regulations governing season lengths and bag limits have been stabilized at "liberal" levels — meaning, in Minnesota, 60-day seasons with six-duck daily limits — for so many years no one expects they will ever change, regardless of the estimated size of North America's duck population.

This year's estimate of 32 million North American ducks, for instance, is down about a third from 2015's estimate of nearly 50 million.

Still, "liberal" regulations will prevail again this fall, as they surely will next year and the next, in part because the USFWS is now setting future seasons using duck-population data that is at least a year old.

Controversial as well, at least in some circles, was establishment in Minnesota last year of an early September five-day "experimental" teal season (the 2022 installment of the experiment started Saturday).

In the 2021 early teal hunt, an estimated 50,000 blue-winged teal were killed by 13,000 Minnesota hunters, with another 93,000 of the same species felled during the regular duck season. This compares to 93,000 bluewings killed in total in Minnesota in 2020, when there was no early teal season, a harvest increase of Minnesota bluewings of more than 50%, year over year.

A sidebar:

While it's true, in my opinion, that some factions of the duck-hunting "community" seem perpetually biased toward shooting more ducks instead of fewer, regardless of habitat conditions and other variables, it's also true that some very smart waterfowl researchers can justify the experimental Minnesota teal season, and can justify as well, scientifically, the feds' liberal hunting regulations. Their belief: There's no harm in either.

That said, even some of those researchers are beginning to question — and here's the duck management controversy du jour — whether spring breeding counts conducted by the USFWS and some states (including Minnesota), upon which all duck management is predicated, have been unintentionally inflating the number of mallards on the North American landscape, particularly the number of hen mallards.

Because mallard numbers are critical to duck management continentwide, if this is true, some rethinking of harvest and/or other strategies might be necessary.

Being questioned specifically is the long-held assumption by duck surveyors flying over spring breeding grounds that the sighting of up to five drake mallards on a pond without a visible accompanying hen by definition meant that, nearby but unseen, was a hen mallard on her nest — which surveyors counted as if they had seen it.

For varying reasons, that assumption is being challenged.

Buttressing this concern are estimates by an older but nevertheless respected way of counting ducks that uses banding and harvest data that seem to confirm that fewer — perhaps far fewer — hen mallards are on the breeding grounds. The same method, in fact, suggests mallards have been declining since 1999.

A big deal? Or just another duck controversy?

Time will tell.

Until then, as a duck hunter, do what you can. When possible, shoot drakes only, Support Ducks Unlimited, Delta Waterfowl and similar groups.

And invite a friend — the younger, the better — to hunt with you.