The Virginia Cooperative Extension recommends feeding blue jays black or gray-striped sunflower seeds along with peanut kernels. Cardinals enjoy sunflower seeds of all types and will most likely appear to feed when the day is nearing its end. Purple finches feast on sunflower seeds and kernels while starlings eat peanut hearts and hulled oats, according to Peter T. Bromley and Aelred D. Geis in an article for the Virginia Cooperative Extension titled “Feeding Wild Birds.” Song sparrows eat white along with red proso millet while house sparrows feed on either white proso millet, canary seed or German millet.
From what I've learned from my mom and grandmother, what's as important as what you feed the wild birds is where you place your feeder. Keep in mind that an area with a bunch of cats may not suit someone wanting to attract ground feeders such as Song sparrows. Think about putting together a feeder that stands along on a pole to prevent cats from getting access to it. Knowing what to feed your outdoor feathered friends will give you hours of enjoyment when you watch them fly down to your yard.