Slow birding

I've made several stops at Lake Leatherwood, and the birding has been slow. Waterfowl variety and numbers are down from earlier in the fall. Sparrows, normally one of the better aspects of winter birding, have been dismal; it's hard to find White-throats. Numbers of all species are low, except Robins, which are abundant. I've seen Eagles several times, and once had three Red-shouldered Hawks. My guess is that the mildness of the winter hasn't forced a lot of birds to come this far south. Even the Fayetteville CBC had a much lower species count than average. Either more cold or more snow might stir things up.