From what I've read and from what I've noticed in nature, unfrozen water is necessary for the continued health and well-being of birds and mammals. Just the other day in fact, a light bulb clicked on in my brain regarding the deer and wild turkeys' habit of staying in just one area during trying (deep-winter) times. I'm nearly 100% sure that it's because they're near a stream that comes up from underground so that it never completely freezes. There has to be more scattered corn to feed on in other areas, but when the lakes are frozen solid they can always be found at the back of this one field where the creek runs.
