Fortunately for bird watchers, most winter birds feed primarily on seeds, including those of shrubs, trees, weeds, and grasses. Seeds are inexpensive, easy to store and package, and much more convenient to handle than worms and mice. Different kinds of birds prefer different types of seeds, but if you're looking for one seed that will attract the greatest number of species, the answer is sunflower. At the same time, certain species do prefer seeds other than sunflower. Blackbirds, for example, like corn, while doves are attracted to both corn and millet.
Some people save the seeds from squash and melons.
These are relished by many bird species, sometimes more than black oil sunflower. They should be spread out on trays and air dried before they're placed in feeders, and if dried sufficiently, can be saved all summer for use the next winter. Smaller birds may have a tough time breaking open vegetable seeds, but if they are chopped up with a food processor, most birds can eat them with ease. Other seeds attractive to birds include safflower, the food of choice for cardinals, and peanuts, which are eaten by all birds except for woodpeckers. Some folks throw out scraps of stale bread, cake, or doughnuts for their feathered visitors.