As noted in this NY Times piece on the Conservation Reserve Program (CRP), any conservation program that depends upon economic incentives will fail when there is a greater economic incentive take a less environmentally friendly position.
In the 1990s we saw this with ecotourism. If someone can make more money developing a golf course community than leaving their habitat in place for birders, guess what they are probably going to do?
Now that agricultural prices are climbing, we can't pay farmers enough to keep them from plowing up habitat to cash in on the latest boom.
Paying people to do the right thing only works until someone is willing to pay more for something else. In the end, if we are willing for it to be all about the money, then the money will win and the birds will lose.