My observation is there are just a lot more animals...
I grew up on a 150 acre farm in southern ohio. We had appr. 20 acres of that under cultivation for tobacco and vegetables. When we saw a deer, it was a momentous and rare occasion. We grew the crops undeterred from rampaging herds of deer. Now, my dad has given up even trying to grow vegetables because the large herds of deer rampage through eating and destroying everything.
The herds of deer in the city I now live in are out of control. We have deer running through shop front windows in downtown Cincinnati, on the expressways, etc. Every part of the city has continually exploding deer populations.
The reason? We've removed every natural predator while we've had an exposion in urban farming, increasing the supply of food to feed the evergrowing hoard of American White-tailed deer.
If I here one more person say "well they were here first!" I will scream. The deer population is growing out of control. They cannot sustain themselves in their traditional woodland/forest habitat and have moved into the cities looking for more food. In 1900 there was an estimated 500,000 US deer population. The population is now estimated to be 20 million. That is why they have moved into our backyards for the first time and are devastating them.
And our elected leaders stand clueless and impotent to address the problem for fear of upsetting the "well they were here first!" crowd or a lawsuit arising from someone getting hurt in any type of controlled kill. With the astronomical price of commercial venison, it being hard to find, and the city sitting on this huge free (since we all subsidized its feeding) supply of deer, one would think one clueless politician could come up with the backbone to start an urban venison harvest and put the meat on the market to sell and help offest city deficits. I for one would rejoice if I could go the local grocery and buy local venison.
I also believe the same increased food supply is supporting the explosion of rabbits, chipmunks, and other ruminants, as well as traditional enemies being eliminated. Cats and dogs used to roam freely, now they don't. Backyards used to be grass, now they're lush landscaped paradises with lots of secluded leafy spaces and undergrowth to hide in and build burrows. As well as the wonderful new increase in backyard tomatoes and other choice veggies.
I'm not a cat person, but I am truly on the verge of going to the animal shelter to pickup a couple kittens to patrol my backyard.