Game and Fish Departments long did not realize that predators were the wildlife managers and biologists were the regulators. It wasnt until several years after the fur market crash of 1988 that became so evident - probably more-so in the southeastern US than the rest of the country because a lot of fur - coons and coyotes in particular - became basically worthless down here.
In the 1980’s, there were a lot of folks with bird dogs. I was killing between 100 and 200 bobwhite quail a year. I was not hunting old grown up farms and field edges - I was hunting commercial timberland clearcuts - which are still very common today. But by the mid 1990’s, it was hard to find a quail. In my area, in the 1980’s, hearing multiple turkeys in a morning was the norm. By mid 1990’s, our state was sponsoring studies to determine what was happening to all the turkeys. Lack of poult production due to nest predation was found to be the cause - with coons being the number one predator. Same thing was happening to quail, and rabbits, and cotton rats. Any of the smaller animals that nested on the ground were experiencing difficulty producing young. Deer were not so much affected; because coyotes were not widespread across the SE - yet. But that was soon to come.
Game departments had just taken predators for granted - and folks who hunted and trapped them. When folks quit hunting and trapping them large-scale - we started running low on turkeys, quail, rabbits, etc. Yes, there have been some peaks and valleys that are largely weather related - but the ability to maintain adequate populations of small game through thick and thin was no more. Game departments, for the most part, dont really directly manage the game - they manage the hunters and trappers who take the game.
With some exceptions, game dept employees are not out there planting food plots all over the state, or burning, or removing invasive plants, or removing predators. Most land is not owned by game depts and it falls on the shoulders of private landowners - with the possible exception of out west where there is so much federal land. Game departments in the south can regulate hunters - but they cant produce quail, or turkeys, or rabbits or deer. If regulation changes alone can not effect population changes, then the game is at the mercy of the predators.
In the SE, game depts could stop all quail or rabbit hunting and it would make no difference. And now, coyotes are fully occupying all available habitat across the SE and fawn recruitment is beginning to suffer. In my own state of AR, we now average .4 fawns per doe. Fifteen years ago it was .8 fawns per doe. And our game dept can not regulate our way to increased fawn production. We are currently able to hunt or trap coyotes year round, 24 hrs a day. Coyotes and weather control fawn production - not the game department - just as coons and weather control turkey and quail populations.
Animals that largely control their own destiny when it comes to reproduction - bears, coyotes, gators, etc are expanding and prospering - they can still be controlled by regulation alone.