Commercial bird seed comes in a variety of mixtures. Cheaper mixtures will contain large amounts of buckwheat, rice, oats, milo, flax, rape seed, cracked corn and canary seed.
What the birds really want to eat is black oil sunflower seeds. To avoid the mess of sunflower hulls, many people decide to spend a bit more and buy the hulled sunflower seeds containing only the “hearts” or “chips” of the sunflower.
If you buy a mixture of seeds, you may find that birds scatter most of the seeds on the ground, trying to get at the sunflower seeds. It is better to place these mixtures in a flat platform feeder, rather that in a hopper type feeder. There will be less waste and fewer seeds will wind up on the ground. Seeds on the ground will attract doves and some birds, but they will also attract mice, raccoons and other critters you may not want at your feeder.
If you are going to feed wild birds you need to continue to do it at least through winter until spring. If the birds become dependent on your feed they may forgo other resources in favor of the easy food you provide.