Conservation: Anything But Average

Variability in weather and habitat has a profound influence on ducks and hunters

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Photo © Chuck Heiting

By Dale Humburg

I grew up in North Iowa, and that's where I received my early exposure to waterfowl hunting. We always looked forward to the end of October for the first major mallard flights to arrive from the north. My dad used to say, "There'll be new birds on the 26th." And on average, he was right.

Looking back through my hunting records, I am reminded that in 1971 and 1995, October 26 was indeed a really great duck day. But in 1972 and 1996, our hunts on that same date were busts—at least from the standpoint of ducks on the grill. Several one- or two-duck days were also included among the many hunts we had on that date from the 1960s to the 1990s. All told, we averaged just over one duck per hunter.

Dynamic patterns of weather, waterfowl habitat, populations, and hunting opportunity held true for North Iowa and still do across years and flyways. Waterfowl habitat conditions, populations, migrations, and hunter activity really are anything but average.

An Average of 4.9 Million May Ponds

When breeding ducks have returned to the prairies and parklands of the United States and Canada over the last few decades, they have found anywhere from 2 million to 8 million May ponds (the standard measure for prairie wetland abundance). Year-to-year variation in regional water conditions is a reflection of the dynamic nature of the breeding grounds. While dry conditions may not be good for that particular year's duck crop, periodic drying is essential for the health of wetlands and the long-term status of ducks. If the water didn't dry up periodically, shallow wetlands would soon lose nutrients, vegetation, and invertebrates important to breeding ducks and their broods.

The same wetland dynamics that are important on the breeding grounds are also in play on migration and wintering areas. Wherever wetlands are found, water-level fluctuations affect cover and food and, in turn, ducks and duck hunters. Wetland managers and hunters may be tempted to strive for stable conditions in a local setting, but this spells disaster for long-term wetland productivity. Managing for constant water levels across years, whether for guaranteed duck or hunter use, ultimately comes at a cost to both.

That's why Ducks Unlimited looks at the big picture of waterfowl management. Complexes of wetlands on a landscape scale are necessary to ensure year-to-year duck abundance. Even then, some spots are wet and some are dry every year. And in some years, such as those in the late 1980s and early 1990s, most places are dry, duck numbers decline, and waterfowlers have to wait it out.

The bottom line from a habitat perspective is wetland habitats are dynamic. It's the periodic drying and reflooding that "drives" them.

An Average of 33.5 Million Breeding Ducks

Driven by year-to-year habitat conditions, breeding duck numbers have ranged from 25 million to 43 million birds in the traditionally surveyed areas of this continent. During the past 35 years, the average mallard breeding population has been 7.2 million birds. Over this same period, however, mallard numbers have ranged from 5 million to nearly 11 million birds, reflecting the response of mallard populations to dynamic breeding habitat conditions.

Duck numbers on migration and wintering areas are at least as variable as those on the breeding grounds. Midwinter surveys, for example, have varied as much as threefold in each flyway over the past 50 years. Weather, habitat conditions (food and water), and disturbance largely account for this long-term variation and for substantial annual differences in the distribution of ducks up and down the flyways.

Regardless of the numbers of breeding ducks or the outlook for the fall flight, local duck populations during the fall and winter rarely follow range-wide trends. The prospects for the fall flight as a function of annual waterfowl production are usually overwhelmed by local habitat conditions, weather patterns, and just a little luck in choosing the right days to hunt.

An Average of Seven Days per Hunter

No two hunters are alike. According to recent U.S. Fish and Wildlife Service (USFWS) estimates, the nation currently has about 1 million active duck hunters. Hunter participation as measured by duck days afield ranges among states from five days per season for hunters in Maine, Minnesota, North Dakota, and Montana up to 10 days afield in Delaware, Illinois, Oklahoma, and California.

Duck harvest per season is even more variable. Averages of 5 to 30 ducks harvested per hunter reflect differences among states and flyways in hunting opportunity, duck populations, and waterfowl hunting success. Considerable variation is also evident in the distribution of harvest among hunters. USFWS data indicate that roughly 10 percent of hunters account for about one-third of the total days hunted and 40 percent of ducks harvested.

I Still Look Forward to This Fall

When I look back on my hunting experiences, I remember the really good days but not the mediocre ones. And I remember the really challenging days, like when I tore my waders, the dogs got in a fight, the sandwiches fell in the water, the motor quit, and we got back well after dark. But that's another story.

Weather drives habitat. In turn, habitat produces ducks and provides hunting opportunity. Hunter success is a reflection of the condition of both duck populations and habitat. These all are highly dynamic, and averages often do not tell the whole story.

I always look forward to next fall because I just know it will be better than average—at least in my mind. And I can't wait until my next trip because I'm certain there will be new ducks tomorrow!

Dale Humburg is chief biologist at DU national headquarters in Memphis.

Beyond the Numbers

Some averages of habitat conditions, waterfowl populations, and hunter numbers are fairly consistent over time, while others are quite variable. Here are some extremes:

  • The annual average for May pond numbers in prairie Saskatchewan is 2 million, but pond numbers have varied widely over time from 600,000 to 3.5 million.
  • While gadwalls have an average annual breeding population of almost 1.8 million birds, gadwall numbers have increased over the long-term from about 500,000 birds in the 1950s to nearly 4 million by the 1990s.
  • Over the past two decades, up to two-thirds of North America's breeding ducks have settled on the prairies of the United States and Canada in a particular year; however, the average proportion of breeding ducks on the prairies is 57 percent.
  • Annual duck stamp sales have averaged 1.7 million since 1961, bottomed out at 1.1 million in 1962, peaked at 2.4 million in 1970, and have been below the long-term average since 1985.