Warm welcome from the Pacific NW, Beth! I've tried different types of seed in my feeders, but have largely opted to just get the least expensive generic mix for my tube feeders and cracked corn for my open ones. The birds that eat directly from the feeders tend to kick the millet out to the ground, but then I get ground feeding birds that seem to like that, so it all gets eaten. How lucky that you get cardinals, so pretty.