North America’s duck population declined this year compared to last year, although most species remain above long-term averages, according to the annual U.S.-Canada waterfowl survey results released Monday.

The annual survey, conducted jointly by the U.S. Fish and Wildlife Service and Canadian Wildlife Service since 1955, estimates this year’s breeding duck population at 38.9 million, a 6 percent decrease from last year’s population of 41.19 million but still 10 percent above the long-term average.

The 2019 survey marks the first time since 2008 that the estimated breeding duck population has fallen below 40 million.

The aerial surveys are conducted in spring, before new ducks hatch, and reflect mostly 2018 habitat conditions, officials said.

“The fact that the numbers are down is a reflection of last year’s dry conditions for nesting ducks,” said Dr. Frank Rohwer, president of Delta Waterfowl. “We know that production drives duck populations, so it’s no surprise that after a year of poor production, the USFWS counted fewer ducks.”

There is some good news. Mallards increased 2 percent to 9.42 million, 19 percent above the long-term average. Green-winged teals rose 4 percent to 3.18 million, 47 percent above the long-term average. American wigeons climbed slightly to 2.83 million, 8 percent above the long-term average. Gadwalls climbed 13 percent to 3.26 million, putting them 61 percent above the long-term average.

Other dabbling ducks decreased, but remain above long-term averages. Shovelers declined 13 percent to 3.65 million, 39 percent above the long-term average. The largest decrease was observed among blue-winged teals, down 16 percent to 5.43 million, but still 6 percent above the long-term average.

Pintails continue to be a problem species, down 4 percent to 2.27 million, 42 percent below the long-term average.

All three diving duck species surveyed showed declines in 2019. Redheads fell 27 percent to 730,000, putting them right at the long-term average. Canvasbacks dropped 5 percent to 650,000, but remain 10 percent above the long-term average. And scaups declined 10 percent to 3.59 million, 28 percent below the long-term average.

Rohwer said it’s likely more restrictive hunting limits will have to be placed on scaups, also called bluebells, starting in 2020.

Tom Mooroman, Ducks Unlimited chief scientist, said hunters could still see good numbers of birds this season, with success often dependent on weather conditions that spur the fall migration.

Wetland and grassland habitat loss — caused by development, agriculture and drought — continues to be a major problem. Across the U.S. and Canada, the May pond count registered 4.99 million, 5 percent lower than last year and 5 percent below the long-term average. Pond counts in prairie and parkland Canada, which covers Alberta, Saskatchewan and Manitoba, decreased 22 percent to 2.86 million, the lowest estimate since 2004 and 19 percent below the long-term average. Parts of Canada remain very dry with better news in the Dakotas where conditions are wet and pond numbers are up.