The results of the U.S. Fish & Wildlife Service’s 2009 Waterfowl Breeding Population and Habitat Survey are in, and the news is good.
The preliminary estimate of total ducks in North America was 42 million, up 13 percent from last year’s estimate and 25 percent greater than the 1955-2008 average.
The survey samples more than 2 million square miles of waterfowl habitat across the U.S., including Alaska, and Canada. The survey estimates the number of ducks on their primary nesting grounds and overall habitat conditions.
Key to populations
The key to waterfowl populations is habitat, measured as the number of ponds, the result of the past year’s snow melt and rainfall. The total pond estimate for the continent’s “duck factory,” the prairies provinces of Canada and northern prairie states of the U.S., was 6.4 million.
This was 45 percent greater than last year’s estimate of 4.4 million ponds and 31 percent above the long term average of 4.9 million ponds.
Ducks require the nesting habitat surrounding ponds and the water itself to provide food and refuge. Simply stated, wet years result in more ducks; drought years cause duck numbers to plummet.
The vast majority of the continent’s ducks nest around the potholes that dot the Dakotas, Minnesota, eastern Montana and Canada’s prairie provinces.
During drought years, however, potholes dry up and farmers cultivate these depressions in the landscape. This forces ducks to nest in increasingly fewer wetlands and that makes nests easier for predators to find.
Drought imposes a double whammy on duck populations — less habitat and higher predation rates. The 1955-2008 averages of duck populations vary wildly, primarily based on the availability of nesting habitat in response to rainfall.
Biologists are at the mercy of the independent and unpredictable powers of nature. Wildlife managers depend on wet years to help duck populations recover from dry years.
That’s why the annual Waterfowl Breeding Population and Habitat Surveys are so important. Only by knowing where populations stand compared to past surveys can biologists intelligently manage duck populations by adjusting duck hunter bag limits.
During drought years bag limits are lowered, sometimes to zero, to protect species whose populations reach historic lows.
Mallards are widespread and abundant across the continent so it’s instructive to focus on them. As mallards go, so go other duck species.
This year the estimated mallard population was 8.5 million birds, 10 percent higher than last year and 13 percent more than the long term average. But these numbers mean little without knowledge of historic extremes.
The best mallard years came in 1956 (10.4 million mallards), 1958 (11.2 million) and 1999 (10.8 million). The worst mallard years were 1965 (5.1 million), 1984 (5.4 million) and 1985 (5 million).
So while this year’s count of 8.5 million is nearly double the worst years’ numbers, it is nearly 2 million birds below the highest counts.
Several other species are having banner years. Gadwalls (3.1 million) are up 73 percent over the long-term average. Blue-winged teal (7.4 million) and green-winged teal (3,4 million) are up 60 and 79 percent, respectively. Northern shovelers (4.4 million) are 92 percent above their long-term average.
Some species, on the other hand, are up for the year but still below their long-term averages. Northern pintails (3.2 million), for example, are up 23 percent this year, but down 20 percent from their long-term average.
Buy a duck stamp
The single best way to guarantee healthy duck populations for the future is to protect more habitat. Hunters, birders and arm chair conservationists can help by buying a duck stamp every year.
Available at larger U.S. post offices and some outdoor stores, duck stamps cost $15 and are required by anyone who hunts waterfowl. A duck stamp also entitles its holder to free admission to national wildlife refuges.
The Migratory Bird and Conservation Stamp — the duck stamp — funnels money into the Migratory Bird Conservation Fund. For every dollar raised, 98 cents is used to buy land for the National Wildlife Refuge System.
Since 1934 the FWS has collected more than $750 million and purchased or leased 5.3 million acres of waterfowl habitat.