The reason was deceptively simple. Due to freak weather conditions, the berry crop along the Katmai Coast had failed； the bears depended on berries to supply calories for their winter hibernation survival. At the same time, the salmon runs were at least average, or even above normal. Space at the best salmon-fishing spots was limited, and turmoil resulted.

　　When the salmon run in Breiter's valley petered out in the third week of September, the bears simply hiked over the pass to Kaflia Bay, where, due to local factors, the salmon run was slightly later and more prolonged. Kaflia already had more than its share of bears wrangling along the creek just 300 yards from Treadwell's camp. Normally the rocky creek bed would be littered with fish parts or entire carcasses with just a bite or two removed. But in this strange season, the bears, scrounging desperately, had eaten every scrap of fish they caught. Tensions ran high as resident bears clashed with interlopers and each other.

　　If Treadwell sensed the growing peril, he gave little sign. One video, taken at the camp, features him explaining to the camera that this is a dangerous place, but they'll be safe here. He knows these bears.