Reprinted from an Aug 17, 2008 column in the Morgantown Dominion Post
Mallard ducks are a stalwart when it comes to waterfowl hunting. But it wasn’t all that long ago when mallard populations were crashing. In the mid-1980's things were dry and grass fields important to mallards were being plowed. This led to a huge decline in mallard duck numbers, followed by shorter seasons and smaller bag limits. Then came the new "Farm Bill" and the Conservation Reserve Program (CRP) that allowed farmers to be subsidized if they put questionable farming lands into hibernation.
Couple that with record high rains and in 1994 we had a new high of 10.8 million mallards. This was mallard heaven. Not just mallards though; other waterfowl species also benefitted from the CRP and rain. However, there was a negative. Many ducks go to Canada to breed, and Canada doesn’t have a CRP program. At the same time our ducks were booming because of CRP, Canada was losing habitat. But our CRP program masked all that, because waterfowl production in the United States climbed.
In 2008, there are other concerns in Canada. The major problem is lack of water. A July count showed a 39 percent decline in the number of ponds in Canada duck lands, and total duck numbers dropped 9 percent from 41.1 million to 37.3 million. Five of the ten most abundant species, including mallards are down by a combined 10 percent for the year. Rob Olson, President of the Delta Waterfowl Foundation, a major duck research organization based in Canada but also active in the United States, writes the following. "The high commodity prices that led to so many CRP acres being broken (in the United States) will likely lead to widespread plowing of grass and more wetland drainage across our already beleaguered Canadian duck factory."
The biggest drop was in canvasback, down 44 percent from 865,000 to 489,000. Northern shoveler’s dropped 23 percent from a record high of 4.6 million in 2007 to 3.5 million in 2008. Northern pintails fell 22 percent, gadwalls down 19 percent, American wigeon down 11 percent, mallards down 7 percent, and blue-winged teal down 1 percent.
Other species improved. Scaup jumped 8 percent, redheads went up 5 percent to a record high, and green-winged teal inched up by 3 percent to a near record high.
The Delta Waterfowl Foundation reported that dry conditions in the eastern Dakota’s brought mallards there down by 24 percent. They also suffered in Montana and the western Dakota’s dropping 36 percent and in Saskatchewan by 12 percent. There is concern in Alberta where pond counts were up 14 percent, but pintail numbers down 66 percent, and mallards down 20 percent.
Back to the eastern Dakotas, even with the dry conditions and the big drop in 2008 mallard counts, that species is still 75 percent higher than the long-term average, and this comes at a time when the wetlands there have dropped by 16 percent.
The question is how can mallards be increasing when the wetlands are decreasing? Simple. CRP. CRP allows millions of acres to go undisturbed, and this makes great nesting cover for many ducks, including mallards. CRP is critical for breeding waterfowl, and that is why the ethanol production that is squeezing CRP (we talked about this last week) is so devastating to wildlife that use CRP fields. This prompted Rob Olson, President of the Delta Waterfowl Foundation to write . . . "CRP masked Canada’s (habitat loss) problems through the 90's, but today, despite the best efforts of conservationists, CRP is going away, exposing Canada’s shortcomings for the first time since the late 80's."
As CRP acres decrease, wildlife managers are now managing mammalian predators to save ducks. If you want to increase nest success, managing mammalian predators works (most of the time). In the 1990's predator populations boomed in the prairies and in some areas they destroyed 90 percent of all duck nests. Some species such as gadwalls, nest in very dense upland cover, giving them extra protection from predators, and that is one reason their numbers, though down in 2008, are up 56 percent over the long term.
But predation can hurt other duck species. One study showed that nest success was 33 percent on areas where mammalian predators were trapped, and only 6 percent on adjacent, non-trapped areas. One Manitoba study site showed that mammalian predators kept nest success below 1 percent. In other words, predators destroyed 99 of every 100 duck nests.
But mammalian predator control does not always work. On a study site in North Dakota, brood survival did not increase with predator control. But the answer might lay with avian predators, because another study showed that on trapped sites there were fewer mammalian predators, but more avian predators (illegal to trap avian predators).
Legal hunting for waterfowl in the United States is controlled to fit the ever-changing population numbers in the wild. Two weeks ago the U. S. Fish and Wildlife Service announced that they are recommending that for this year, in three flyways, canvasback hunting be closed due to low populations and scaup hunting be restricted because of long-term declines.
Several biologists conclude that even though duck numbers are healthy in general, the recent high use of corn for ethanol will impact CRP and this could have a huge negative effect on waterfowl. OK, I’ll give you that, but just look how much the use of corn in ethanol production has lowered your gas price at the pump? Yea, right.
