Always be sure to add cornmeal, small seeds, or some type of grit to peanut butter mixtures. Peanut butter alone is too sticky and hard to digest. In some cases it may even glue a bird's mandibles shut. It is a good idea to offer grit as a staple during the winter. This is especially true during periods of snow, when natural grit is more difficult to find.
Birds have no teeth and depend on grit in their gizzard to help digest their food.
Cornmeal, coarse sand and commercial mixtures are all acceptable forms of grit. Winter can bring crowded conditions to your feeder making birds more susceptible to disease and parasites. Now is a good time to clean your feeders and the area around them. Clean feeders with a bleach-water solution. Make the solution nine parts water to one part bleach.