Responses of brown bears to human activities at O'Malley River, Kodiak Island, Alaska

We classified levels of direct response of brown bears (Ursus arctos middendorffi) to aircraft, watercraft, and groups of people on the O'Malley River area of Kodiak Island, Alaska. General public use occurred on the area in 1991 and 1993, whereas structured bear viewing programs used the area in 1992 and 1994. Brown bears displayed high (running) or moderate (walking away) response on 18 (48%) occasions when fixed-wing aircraft flew over the animals <100 m above ground. Three of 4 helicopter flights <200 m overhead and 9 interactions with watercraft at ≤200 m distance also elicited strong response. Encounters between people and bears resulted in strong responses from bears more frequently (37%, n = 134) during years of general public use than in years of structured bear viewing (6%, n = 72, P < 0.0001). We suggest that higher levels of low or neutral response by bears to encounters with guided bear viewing groups was the result of consistent and predictable patterns of human activity.