MY HOMEMADE BIRDFEEDER, MADE ESPECIALLY FOR MY CARDINAL PAIR.
Mrs. Cardinal enjoys a yummy sunflower seed from "her" feeder. The other birds can't fit or they make this lightweight feeder spin, so they don't bother with it.
My feeder is made from:
A 2 liter coke bottle with holes cut in either side and small drain holes in the bottom, a small hole in the screw-on cap
A chopstick
A plastic carton lid
A wingnut (on top, to weigh down the lid)
A small rock (in the bottom of the feeder, to add a little weight for stability)