Use of a garbage dump by brown bears in Dillingham, Alaska

We studied brown bear (Ursus arctos) use of a garbage dump in Dillingham, Alaska, USA, in 1997 prior to an impending dump closure. During the summers of 1991–96, incidental observations of bears at the dump indicated 40–80 individuals fed there. Seventy brown bears used the dump from 19 May to 29 September 1997, including 25 adult males, 11 subadults (4 females, 7 males), 9 females with cubs (n = 19 cubs), and 6 adult females. Males and females constituted 63% (n = 32) and 37% (n = 19) of the adult population, respectively. Seventeen bears were predictable users and showed regular temporal patterns of use. The dump appeared important to these bears, and they could be adversely impacted by its closure. The total number of bears observed per night varied from 4 to 33. Peak use occurred on 1 July and 9 July and coincided with low availability of high quality natural foods, suggesting the dump was a supplemental food source to most bears. This indicated closure would probably have minimal effect to most bears because it was not used by a consistently high number of them throughout the season. Subadult use mainly occurred in June. Adult males predominated in July and August. Females with cubs predominated in September when use by other age classes was negligible. Subadults were the least and females with cubs were the most socially dominant bears, respectively. Garbage pile size was reduced and kept small throughout the summer to minimize bear use. Smaller pile sizes restricted the number of bears that fed on garbage. Management recommendations for improving the safety of bears and humans at dumps in other rural areas include electric fencing, tighter enforcement of government waste disposal regulations, more efficient dump designs, and restricted human access.