It’s a mixture of grasses, some switch grass, some little and big blue stem, some Indian grass, and some clover and other broadleaf mixed in.
But here is the issue.
The property has not changed in 20 plus years, except there are more and better milo food plots the past 12 or so years. And there is two more small ponds as water sources for wildlife.
It had excellent pheasant population for many years, going back into the 1990s, so I have to think habitat is not the issue. The habitat supported great pheasant numbers in the past.
The population was wiped out in the summer of 2012, when there was many consecutive weeks of 100-110+ degree temperatures and no rain. That summer was devastating and way out of the ordinary. Since then, summers and winters have been relatively normal.
Since then, the population has stayed very low.
Not saying you're doing anything wrong, but I'll add some additional comments... based on the theory of DIVERSITY
It sounds like you have a good variety of grasses, but what is your forbs and legumes situation like? While phez love large expanses of grass for loafing and escape cover, they have to have a DIVERSITY of other plants to sustain their life cycle. Additionally, extremely dense blocks of grass are not good brood-rearing cover.
I have a much smaller piece of ground than you do- mine is only 60 acres in southern Iowa where quail are more likely to be found than phez- but flora DIVERSITY have been tremendously beneficial for my pheasant population. My approach is to manage the property primarily for quail, and let the phez benefit from it as much as they can. The absolute best brood-rearing cover that I've experienced is CP-42 pollinator blend. A mix of grasses, flowering and seed-producing plants, it is just what the doctor ordered for young phez and quail. Enough grasses to offer patches of cover, a multitude of flowering plants to attract insects for the chicks, and seed-producing plants later in the season as the chicks are transitioning from a protein-based diet to a grain-based diet. And it offers enough bare ground at the bottom for the chicks to have sufficient mobility.
I keep about half of my CRP in CP-42 and half in CP-25 (native tallgrass prairie) so the birds have a good mix of brood-rearing, nesting and winter grass cover. I have five sorghum food plots, ranging in size from just over an acre down to about a 1/4 acre. Each year, I allow 2 of the 5 to lay fallow, resulting in a wonderful mess of old sorghum stalks, ragweed, foxtail and wildflowers- almost as good as CP-42 for brood-rearing and carries food benefits well into the winter.
My largest, primary food plots are Blizzard Buster sorghum. I don't know of anything better that provides both food and winter cover. However, simple mowing and shallow tillage of overgrown grassy or weedy areas is a great approach for smaller, supplemental food plots, too. It knocks back all of the invasive and/or cool-season grasses and allows the weed seeds like ragweed and foxtail to germinate. Broadcast some German millet in there, too, and viola! you have a little food plot with very little work invested. Now you have a DIVERSITY of food sources.
I have a couple of cedar thickets adjacent to the CRP fields that also helps in the winter, and I've created 3 hinge-cut thickets on the edges in other areas for escape and thermal cover. Grassy cover, shrubby cover and brushy cover- you guessed it: DIVERSITY.
Finally, I'm in the process of trying to remove any hardwood trees in or adjacent to my grassland, within reason. They are nothing but perches for raptors.
Best of luck in your efforts.