The majority of wetlands I hunted along the Mississippi River growing up are now incapable of holding water. Chisel plows ripped out the bottoms, and field tile drained the rest.
I nearly gave up duck hunting because there was nowhere left to hunt that wasn’t an arm and a leg to lease every year, and there was no habitat left for the birds to exist on without going shot at. If they can’t rest places and trade around to small wetlands, they leave. The ones that don’t just sit on a million dollar flooded corn refuge that represents the only area they can do that on, and then never leave because there’s nowhere to go except Arkansas.
When the river flooded and filled the borrow pits, or backflooded fields, there were birds in abundance. But that’s getting to be rare, too.
You can say what you want about agriculture being good for waterfowl, but it’s absolutely proven catastrophic to pintails, and nearly as bad for the average waterfowl hunter.