What is the purpose of gathering biological data? To better manage our flocks, waterfowl professionals tell us.

The volumes of duck data compiled each year suggest waterfowl management has entered the “Age of Reason,” a time when rigorous statistical analysis permits it to better manage our ducks and prevent the further decline of our flocks.

Why, then, are waterfowl professionals ignoring their own data, especially the alarming data involving wood ducks?

The wood duck is waterfowl management’s most celebrated success story. As most of us know, by the early 1900s many believed the species was headed for extinction, its numbers decimated by plumage hunters.

The signing of the Migratory Bird Treaty in 1916 gave the wood duck total protection from the gun. This allowed our most colorful duck to begin slowly rebuilding its numbers. This protection continued until 1941 when hunters were allowed one wood duck per day.

For nearly two more decades the wood duck’s status was carefully monitored. In some years hunters were allowed to kill one daily, in other years the season was closed. Then in the early 1960s one wood duck per day became the standard, a limit that eventually was raised to two daily in the three eastern flyways.

At the same time, the wood duck’s eastern population expanded its range westward into parts of the Central Flyway where 50 years ago it was unknown. Its population growth and range expansion is testimony to what proper duck management can achieve.

Its growth has been so remarkable that today it is the second most common duck in the bag of Atlantic and Mississippi Flyway hunters.

But recent data raises troubling issues for both wood ducks and waterfowl management, especially in the Atlantic and Mississippi Flyway that account for nearly 90 percent of the

U.S. wood duck kill.

We begin with the Atlantic Flyway. The first graph shows average annual age-ratios for each decade since the 1960s. This tells us the number of juveniles per adult in the hunter’s bag and is a measure of reproductive success. The higher the age-ratio, the greater the number of juveniles in the fall flight. The second graph plots the age-ratios by year from 1990 to 2001.

Atlantic Flyway Age-Ratios

60s 70s 80s 90s
Decade

Atlantic Flyway Age-Ratios

90 91 92 93 94 95 96 97 98 99 0 1
Year

As you can see in the top graph, the average annual age-ratio during the 1990s is the lowest since record-keeping began. The lower graph displays the year-by-year declining trend from 1990 to present.

Now, let us turn to the Mississippi Flyway.

Mississippi Flyway Age-Ratios

60s 70s 80s 90s
Decade

Mississippi Flyway Age-Ratios

90 91 92  93 94 95 96 97 98 99 0 1
Year

Once again, we find the 1990s produced the lowest average annual age-ratio ever recorded in the Mississippi Flyway. The year-by-year trend from 1990-2001 also reveals a decline, although at a much less steep rate than the Atlantic Flyway.

Of course, juvenile productivity must be balanced against the sport kill. What does U.S. Fish and Wildlife Service harvest data tell us?

We begin in the East.

Atlantic Flyway Kill

90 91 92 93 94 95 96 97 98 99  0 1
Year

As you can see, the year-by-year kill in the 1990s rose steadily until 1998, but has been declining ever since.

Mississippi Flyway Kill

90 91 92 93 94 95 96 97 98 99 0 1
Year

Once again we find the kill has steadily increased in the Mississippi Flyway, but today is in decline, just like the Atlantic Flyway. The reported 1999 kill of 958,915 wood ducks was the highest ever recorded in the Mississippi Flyway.

How do these declines in productivity justify management’s decision to significantly increase the kill, as occurred when we adopted Adaptive Harvest Management in 1995? The combination of declining juvenile productivity and a long-term increasing kill followed by a decline in the harvest suggests to some highly esteemed waterfowl biologists that wood ducks are in serious trouble.

Frank Bellrose and Don Holm, co-authors of the definitive work Ecology and Management of the Wood Duck, concluded in 1994 that “because wood duck populations exhibit particular sensitivity to hunting losses, changes in regulations that permit a higher harvest should be made with caution.”

They further suggested the average 1978-1990 annual sport kill of 981,500 wood ducks in the eastern United States amounted to overharvest.

Although waterfowl managers might “strive to maintain this level of harvest to partially compensate for the reduced population of other species,” they said, “to overharvest for long …would bring the wood duck into a decline that likely would be precipitous and certainly unpopular among hunters.”

More importantly, the data reveals that since Adaptive Harvest regulations went into effect in 1995 the annual wood duck kill in the three eastern flyways has increased from a 1978-1990 average of less than one million to a 1995-02 average of 1.2 million. Moreover, the fact the kill has declined for the past three years from the 1999 peak of 1.5 million strongly suggests the eastern wood duck population is declining.

Art Hawkins, a retired U.S. Fish and Wildlife Service biologist, noted this year at a meeting of the Wood Duck Society cited the record 1999 wood duck kill in the Mississippi Flyway and asked, “Did that lofty figure constitute over-harvest? I think so.”

Which brings us back to the question: Why are our waterfowl managers ignoring their own data that suggests over-shooting is causing a decline in numbers of wood ducks, especially when this conclusion is affirmed by long-time waterfowl professionals of impeccable reputation?

Doesn’t this decline affirm critics who declare the U.S. Fish and Wildlife Service, the flyway councils and some biologists consider a dead duck more valuable than a living one, a belief that reflects management’s stated goal to optimize the harvest?

Doesn’t this disregard for the data suggest one reason why are our migrant flocks are declining – and likely to decline further in the near future?