During the five years of this study, however, Boyce and his colleagues found that mountain lions were the biggest cause of mortality. Although this level of lion predation might be the norm for larger populations of bighorns in other areas, the endangered Penninsula bighorn might not be able to withstand it. Some managers think that culling the lions is the most efficient course of action, but one that would meet fierce resistance. Since 1972, Californians have repeatedly voted in measures that ensured the mountain lion's protection. Whatever decisions are made to solve the lion-bighorn problem, should be guided by research that brings to us an objective understanding of the animals' themselves.
Questions concerning lions as well as bighorns are relevant.
Holly Ernest, a graduate student working with Professor Boyce is trying to identify the lions making kills by examining mountain lion DNA, obtained through feces, and saliva from bite marks on carcasses. Preliminary results suggest that during the five years of the study, as many as eight different lions have killed bighorn sheep in this area. In the end, a coalition of wildlife agencies, using the findings from research such as that being done at UCD, will have to decide the best way to manage the two species so that both survive in the region. In the meantime, wildlife managers are working to minimize the other threats to the Peninsular bighorn sheep that have in the past been more serious than lion predation. These include disease, drought, and, most serious of all, those golf courses and developments that creep inexorably into bighorn habitat.