YES! You are correct.
While all the foods listed will be attractive to birds, black oil-type sunflower seed is the preferred food for the most winter birds. It is small enough for even chickadees and large enough to attract finches, cardinals, and jays. It is also highly digestible and gives birds good energy for its weight. So, if you're only going to feed one thing, black oil-type sunflower seeds are the best choice.
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