The best seed cylinder for when starlings, grackles, and cowbirds are dominating your feeders.  These birds can't open the tough safflower shell, but cardinals, house finches, and chickadees love it.  Even if you're not having trouble with grackles and starlings, if you have multiple feeders, we highly recommend having one dedicated to straight safflower.  This will raise your chances of getting cardinals and the other birds that like it since they won't have to compete with some of the other more aggressive birds that can't eat it.  The only downside of the safflower cylinder is that woodpeckers won't eat it either.  If you want a version of safflower that is less mess, can't sprout, and the shells blend in with dirt and grass better, check out the Golden Safflower Cylinder.  If you need to be squirrel proof, get the Flaming Hot Feast Cylinder.  While it is true that squirrels like safflower less than other seeds, it is not a true squirrel-proof option. You need to have a specific type of feeder to offer this food as it is a cylindrical block of seed held together with gelatin.  Check out all the options of Cylinder Feeders. We highly recommend the Hanging Cylinder Feeder with Dome.