I called in 5 bears in No. Cal on one trip. The success was because I had good information from a trapper that knew where and what the bears were eating. At the time it was tan oaks. The next year I came back later in the season, Thanksgiving, and called for 5 days with no success. It snowed the day before we arrived and I think changing weather slowed down their desire for meat. There were plenty of bears that we kicked out walking to stands.
Other hunters agree that better results are had earlier in the season.
I always made long stands but my first called bear was dead in 2 minutes on the first stand. Most showed up quickly but then again, the area was loaded with bears.
The call was a Crit'r call
Good hunting
