There was an unprecedented number of bear attacks last year, and conflicts between people and bears, especially grizzlies in Yellowstone National Park, are likely to rise in 2011. Wildlife officials from New Mexico to Washington State are reporting an increase in bear encounters. Bear managers in Wyoming alone captured 52 grizzlies last year, and more than 80 bears were killed in New Mexico — more than three times as many as 2009. Although only two people were fatally mauled by grizzlies last year, experts say that’s the most in one year in more than a century. What’s causing all the attacks? Hunting and trapping nearly drove grizzly bears to extinction until they were added to the endangered species list in 1975, but the grizzly bear population in Yellowstone has since climbed to 600,100 more than the recovery goal. Not only is there a large number of bears, but there are also a large number of hungry bears. Nuts, berries and pinecones were in short supply last year because of poor growing conditions so more bears ventured into human territory.