Of course predator control can work, but is very expensive and practical only on very small areas devoted to the production of a few, sometimes a single game species, not the general countryside.
A big part of the problem, at least with trying to increase duck nest success in the Prairie Pothole Region that I am familiar with, is that there are so many kinds of nest predators. Thus the predator control must be intensive, and that is nearly impossible now that the best tools like cyanide guns, poisoned grain, and strychnine drop baits are no longer legal for even professionals to use. Even then, there are obstacles like obtaining landowner permission to kill furbearers such as mink and kill cats that range out from farmsteads. Around here, studies show it takes many years to reduce populations of even the more common predators with normal methods like shooting, den cleanouts, trapping and winter aerial hunting, even on an area as small as 10 mi2. The neighbors just keep moving in to the unoccupied habitat created. Also keep in mind that once those duck eggs hatch and the ducklings complete the perilous trip to a suitable natal wetland, another suite of predators, mostly birds, begin to take their toll.
So in this intensively farmed region, I would rather see tax dollars spent on habitat creation or improvement and let individuals, hunting clubs, or conservation organizations control predators with private dollars on any land they have access to.
