Cardinals rarely visit our urban yard and if they do they’re extremely skittish. The main problem is competing mobs of House Sparrows (Passer domesticus). I’m glad to say that this cardinal species-specific feeder has improved conditions for the cardinals.
Unfortunately some House Finches (Haemorhous mexicanus) have figured out how to access the safflower seeds by pushing their beaks and flapping–creating a false, heavier weight on the perch. I’ve added some bamboo pieces to limit this but overall it’s not a concern unless House Sparrows learn this maneuver too. Even then, birds will be forced to take turns and House Sparrows always seem to fight with each other rather than cooperate or have patience.