I am very curious to see if different parts of US have experienced a massive predator shift over the decades like my area has...[?]
I am a good bit over 70 and I have often mentioned how the predator population has lost respect for and the fear of man.
The real thing that happens when Man moves in is that humans modify the environment to suit the purposes of human beings and these changes suit the purposes of
most chicken predators mostly because man and chicken predators both like to eat chicken eggs as well as the chickens themselves.
Large areas of un-touched wild land is not the predator paradise that some of you may think. One reason for this is that wild prey species wax and wane in response to the seasons while your chickens, ducks, guineas, etc. are on hand (or on the menu) year round.
I don't know how reliable the figures are but Wildlife Professionals tell me that there are more white tailed deer in America today than when Columbus first touched the islands of the Caribbean.
For instance wild flocks of starlings, grackles, Brewer Blackbirds, and red wing blackbirds were once common in my home area. They would often pass a single point in an uninterrupted stream for 2 or 3 hours while going to roost every evening. At this time there was many small cow feed lots scattered around the Tennessee Valley and these millions of birds had a easy life or a easy time finding all the spilled grain that they needed to live the good life.
The same thing happened on the Great Plains when humans first began abandoning farm buildings, planting trees, or scrapping cars, trucks, and farm machinery. All of these things made great escape and nursery sights for raccoons, and crows, which were once scarce. The upstart was increased duck nest predation and increased chicken flock predation on the Great Plains.