Specifically, Cardinals.
We have a pair that pays us a daily visit. They love whole Peanuts and Sunflower seeds. Problem is, so do the Squirrels. Damn tree rats hoover them up as soon as we put them out.
Solution: White Safflower seed.
Cardinals love them, vermin does not.
Try Suet Cages.. I make my own bird cakes twice a week. The rascally squirrels can't get to them. I have six Cardinals and 4 American Robins, Gold finches, Towees.. and others I can't identify.. The cages will cost under $2.00 each.
The possums or coons kept dragging my suet cages away. I eventually moved one up next to the road and it stopped that.
Anyway as for the cardinals, I have hanging feeders. The squirrels seldom bother the ones on shepherd's hooks and I don't really care if the get in the ones hanging from tree limbs since I do put corn cobs out nearby for them periodically.