I made this bird feeder from a Tropicana orange juice plastic bottle, the top of a plastic bottle that contained rice, a lid from two gallons, plastic paint can, and a wire coat hanger. Just turn the orange juice bottle upside down, cut a hole just a bit smaller than the rice jar top, and use clear silicone to glue the two parts together. I added strength by putting some pop rivets around this connection, but sheet metal screws work, too (be sure to pre-drill first).
Then I cut holes in the bottom with an X-Acto knife for the bird food to spill out. Next, cut a hole in the paint lid for the orange juice bottle to attach and thread the juice lid on to hold the lid on. All that is left is bending the coat hanger to shape and put it in the orange juice bottle through a pre-drilled hole and attach three or four bolts to act as perches. This is a great project to do with your kids. The design is squirrel-proof.