To make a bird feeder from a soda bottle, insert a wooden dowel near the base of the bottle, and cut small feeding holes 1 to 2 inches above the dowel. Insert a metal screw hook into the cap. Fill the bottle with birdseed, and hang it outdoors.
Start with a clean, dry bottle to avoid spreading disease or contaminants to the birds. Allow the inside to dry fully before you start making the bird feeder. Two-liter bottles work well because they hold more birdseed and allow more space for perches.
Thin dowels make sturdy perches for the feeder. Cut or drill holes for the perch about 1 1/2 inches from the bottom of the bottle and opposite one another. Make the holes just large enough for the dowel to fit. Slide the dowel through both holes so it goes through the middle of the bottle with extra length on each side. Use a small amount of hot glue on the outside of the bottle to secure the perch.
The feeding hole should only be between 1/8 and 1/4 inch in diameter so the seed doesn't spill out. Adjust the size of the holes based on the size of the birdseed you use. You can add another set of perches and holes if desired. Place the second set 2 to 3 inches above the first. Place the second perch perpendicular to the first perch.