sam telford says the ideal size of the blue hills herd is about 100. but is that a realistic goal?phanie boyles griffin is the senior director of innovative wildlife management and services with the humane society. >> attempting to reduce deer populations, to reduce the transmission of lyme disease has not been shown to really be effective. you would have to get your populations so low, and that's really just not achievable on a lot of these urban systems. >> reporter: in denny swenson's neighborhood, most people are committed to thinning the herd, but there is some ambivalence. >> killing them wasn't my first goal at all, and i'm so heartbroken that we have to. but for the health of the deer and the health of the forest and the health of the people that visit the forest, we need to manage this problem. >> reporter: the explosion of the deer population in suburbia and the rapid rise of lyme disease are warning signs of an ecosystem out of balance. the hunt for solutions won't be cheap, easy or fast. miles o'brien, the pbs newshour, milton, massachusetts. >> woodruff: the u.s. senat