Having successfully harvested a deer this season, I experimented with using tallow as a food source for birds in place of suet blocks. Tallow is a very hard waxy fat found under the skin and within the body cavity of the deer. It used to be used to make candles, though not as good a quality of candle as beeswax.
Anyway, I placed a few pieces in my suet feeder. Although ignored the first few days I now a have a host of Downy Woodpeckers, White-Breasted Nuthatches and one very aggressive Red-Bellied Woodpecker regularly feeding off of it. Another resource from my harvest put to good use, otherwise the tallow would be discarded.
Cedar Grove, NC
PS- Most awesome sight while deer hunting this year- watching a male Wild Turkey for more than an hour as it sunned and preened itself on a log.