If you want to construct a birdhouse with your children, you don't need to purchase expensive lumber. Instead, you can use recyclables found around the house, such as a used half-gallon milk carton. The kids can construct the birdhouse themselves without handling dangerous tools. The project will also allow them to decorate the birdhouse using non-toxic paints.
Wash out a half-gallon sized milk carton, and allow it to dry completely for 30 minutes.
Cut a hole in the side of the milk carton, positioning the hole so that it's about two to three inches above the bottom edge of the carton.
Paint the outside of the milk carton using colourful tempera paints. Be creative. You can paint the carton with a single colour, or you can paint a picture or design using multiple paint colours. Allow the paint to dry for 30 minutes.
Add a clear waterproof glaze over the painted carton. This will make the paper waterproof and will prevent the tempera paint from washing off in the rain. Allow the glaze to dry for 30 minutes.
Punch a hole out of the top edge of the carton birdhouse using a single hole punch, then thread a 12-inch piece of twine through the hole. Tie the twine into a loop. Use the loop to hang the birdhouse on a tree branch.