You must be the kind of guy that takes a low mileage used car and immediately puts a dent in the door and takes the trunk lid off. I mean sure, you can throw the groceries in the back a lot easier after that, but dang….
The pheasant population is on the decline in SD as well, but not as much. They don’t have as much (yet) marginal land under cultivation. But Iowa is pretty much dead for birds.
In addition, modern machinery leaves much, much, much less waste grain. Genetic alteration of plants, so less falls over or off prior to harvest. Not as much to eat. Most hill ground has been converted from having long, lush grass sloughs to tile and terraces. CRP is dead. Fewer places to hide.
Long cold winters, wet-ass springs, dry summers. Perfect storm of bad weather.