The trend is good news for hunters, bird watchers, and biologists, experts say, but also for people who live near areas like San Francisco Bay, which is a key stop for migrating ducks every fall along the Pacific Flyway.
"I'm excited. It's encouraging," said Walt Rhodes, a flyway biologist with the U.S. Fish and Wildlife Service, who flew thousands of miles surveying the birds this spring.
"It lets you know that maybe we're doing something right," he said. "Overall, it seems like things are headed in the right direction. A wetland without waterfowl is just not right."
More than a dozen duck species fly south every year for the winter, some traveling thousands of miles from Alaska, the Yukon Territory, the Dakotas and other Northern areas to warmer wintering grounds across the United States and into Mexico.
There, the birds fatten up and head north again every April to breed, lay eggs, and raise a new generation for the annual migration. But when they return north, the birds need wetlands and wild grassy areas to stay free from predators and raise their young.
Researchers say favorable weather conditions in 2010 and 2011 - mainly rains in the spring and significant snow melt - have created lots of new wetlands and ponds in the Canadian prairies where ducks breed. Places such as Saskatchewan are so important to waterfowl populations, they are known as the "duck factory."
"Last year, we made a pile of ducks. This year, we're counting them," said Frank Rohwer, the scientific director for Delta Waterfowl, a research and advocacy group based in Bismarck, N.D.
More ducks means more food for predators, such as peregrine falcons, golden eagles, foxes, and bobcats.
Drought conditions in the 1980s and a steady loss of wetlands to farming and development sent duck populations crashing by the mid-1980s to about 25 million. Alarmed, federal regulators reduced the hunting season to 30 days and the bag limit to three ducks per hunter in many areas. Today, by comparison, the hunting season and bag limits have doubled.
Along with a run of good weather years, several key events sent populations rising to today's record levels.
Despite the positive trends, however, there are significant concerns still looming.
This year was drier than normal across much of Canada and the Northern Plains. This week's survey found a 32 percent reduction in ponds there compared to last year, although the total number is still up slightly from the historic average. That could mean duck populations in future years may fall if dry conditions continue.
"Ducks are an indicator of the overall health of the environment," said Mark Biddlecomb of Ducks Unlimited, a nonprofit conservation and hunting organization, in Sacramento, Calif.
"If we can sustain numbers of birds like we're seeing now in Canada and the U.S., then we have a healthy environment. And if the numbers are going down, then the environment is not what it should be."