I think it's because our forests are healthier. About 20 years ago the PA Game Commission implemented "herd reduction" for deer and increased the number of doe tags to allow for more deer to be killed per season. This reduction allowed for more understory in the forest which increased available food for other species. I believe the reductions also happened in the fringes of where the bears lived, allowing their populations to increase and in turn spread.

We have also seen an increase in bears populations along our border with NJ. NJ has had a few canceled bears hunts which have allowed their bear population to climb. Bears swim across the Delaware river and find a nice home here.