A neighbor of my mothers' was cleaning out her house and garage. She had birdcages she was tossing. When mom told me about them, I said for her to go get them for me. Before I got up to her house to get them, I visited my friend, Judy, and saw that she was using birdcages as feeders. This is a picture of my cages. I will try to upload the results later, but Blogger isn't uploading right now. I tried twice and it took over half an hour to reject the upload.
What you do is take the extra stuff out, if any is in, then drill a couple of small holes in the tray for drainage. Snip a few cage wires here and there for access for the birds, fill the bottom tray with seed, and hang out somewhere. The round feeder is on my patio, the square one is on the front porch. It took about a week for anyone to get the idea, but since then they have hosted finches, cactus wrens, and a few birds that I don't know the names of. These feeders allow me to enjoy the birds, the cats to enjoy the birds while the birds remain unmolested, the seed stays put and isn't scattered everywhere, and the doves aren't a pain in the tush. I empty out the spent seed on the ground out in the yard for the doves. The small openings I cut keep out the marauding Scrub Jays and Mockingbirds. I am anxious to see if the cardinals find them. But mainly the finches are in hog heaven.