Every winter I feed black-oil sunflower and thistle, as well as suet and peanuts, to attract my "winter birds." I seem to have birds that stay all winter and come March, they go into the woods to start nesting, while birds that prefer our more open, bushy area, come for the spring/summer. Anyhow, when March arrives, along with hundreds of grackles and starlings, I switch from sunflower to safflower, so my finches and cardinals are still happy, but I keep away the hoards of undesirables. This winter I hardly had any cardinals. As soon as the sunflower went up, they seemed to disappear. Now that I am being over-run by house sparrows, I just switched to safflower, and within a half an hour, I had 3 cardinals at my feeder. So, my question is, what seed does your cardinal prefer, and how do they know, so quickly, when you put out there favourite food? Is it sight, or smell? Or what? :h?: