Measure the perimeter of the birdcage around the location where the birdseed dish is attached.
Cut a piece of mesh fabric 6 inches wide and 3 inches longer than the cage measurement taken in Step 1.
Fold a hem on each long end of the mesh and use an iron to press it. Pin along the long edge of each hem.
Cut two strips of elastic band equal in length to the perimeter of the birdcage.
Thread an elastic band through one hem, between the pins and the folded edge. Pin one end of the elastic band to the end of a cardboard strip, which will act as an anchor. Hold the cardboard in place as you stretch and pin the bands along the long edge of the hem until the length of the elastic is equal to the length of the hem. Repeat this process with the other elastic band and the other hem.
Sew the hems in place, using a zigzag stitch. Remove the pins along the hem.
Bring the short ends of the mesh together to make a circle. Sew the ends of the elastics together. Remove all the pins along the elastic.
Sew the ends of the mesh together with a zigzag stitch to finish the bird guard. Stretch the guard around the birdcage.