I agree the boars would be wandering and looking for a sow. Here the bears are hungry and are currently looking for anything to eat as well. With the green stuff growing in right now and new fawns being born the bears are finding food once again. They have been live trapping bears here that are coming into towns and getting into dumpsters and ect.. So i am not sure what is wrong with your site. My guess is you and whoever is leaving to much sent around for thier comfort..

For as far as grizzlys driving black bears off I can only imagine that they would. Most bears can be very territorial.. Good Luck on figuring out what is going on..