In 1989,
Delta Waterfowl adopted a program that encouraged hunters to shoot fewer hens, called “Voluntary Restraint.” It came on the heels of a string of poor hatches and a sharp drop in overall duck numbers. The goal was to boost survival of hens and ultimately rebuild duck populations on the backs of those additional females that survived hunting season. Since then, a legion of hunters turned voluntary restraint into a religion. Not only do they refuse to shoot a hen, they chastise others who pull the trigger on anything but a drake. Whether a result of peer pressure or a conservation ethic, there is no question hunters are selective about what they shoot. A 1991 survey of Illinois waterfowlers showed 74 percent avoid shooting hen mallards. According to wing survey data, hunters kill between two to three drake mallards for every hen they harvest. That ratio has been relatively stable for at least 20 years.
But what about ducks whose sexes look alike? Male and female black ducks are nearly impossible to distinguish, which explains why an equal number of each gender are killed each year. Based on the “dead hens don’t lay eggs” mantra used by so many conservation-minded hunters, it would seem logical that black duck populations would be struggling. But they aren’t. Although black duck populations are well below long-term averages, due largely to the continued loss of winter habitat, their numbers have been relatively stable for the past 15 years.
There are no studies that have specifically examined the effects of VR on duck populations, but many biologists agree it has little measurable effect.
“If you look at species with sex-specific harvest restrictions—and there’s only one: mallards—you will see that there are no discernible differences in long-term population trends compared to species that don’t have sex-specific harvest restrictions,” says Louisiana Department of Fisheries and Wildlife waterfowl study leader Larry Reynolds.
That is because hunting plays a minor role in duck mortality. Graphs of most duck populations generally follow the same zigzag pattern as the amount of water on the primary nesting grounds. So does the number of ducks killed by hunters. Good nesting conditions in the spring, not a decline in harvest the previous fall, equal more birds.
“Studies have shown that hunting-specific mortality of hen mallards is about 7 or 8 percent. In other words, 93 percent of all hen mallards are unaffected by hunting regulations. The annual mortality rate from all causes is about 40-45 percent for hen mallards, and thus hunting accounts for probably less than 20 percent of annual mortality,” says Reynolds.