Cut a large rectangle out of each side of a clean, dry, half-gallon milk or juice carton. The rectangle should leave plenty of space around it to provide a frame for the birdhouse. Leave the top of the carton intact, and use school glue to glue the folding part shut. The top part will mimic the roof of a gazebo.
Decorate the birdhouse to look like a real gazebo by cutting green vines, colorful flowers or lattice out of construction paper. Glue the decorations around the frame and on the roof of the birdhouse.
Punch holes in the roof of the birdhouse, and thread a sturdy string through them. Tie the string to form a loop, which you can use to hang the birdhouse from a tree.
Fill the bottom of the birdhouse with birdseed. Take the house outside, and hang it from a tree branch.