Ornamental gourds dry to have a hollow interior and harder exterior, suitable for many decorative and utilitarian purposes. Building a birdhouse using the gourd as a natural home for visiting birds can be a simple project. Dipper and bottle gourds are two commonly sold at craft stores or grown in the home garden that are a suitable size and shape for use as bird houses.
Drill a hole for the entrance in the front of the gourd in the center of the lower swollen part of the gourd. Drill a 2 and one-four-inch hole for purple martins or a 1 to 1 one-eighth-inch hole for wrens and chickadees.
Drill three one-eighth-inch holes in the bottom of the gourd so that bird waste and water can drain out. Space the holes evenly apart.
Drill a one-fourth-inch hole directly beneath the entrance hole for the perch. Center it beneath the hole.
Coat one end of a 4-inch length of one-fourth-inch diameter dowel with wood glue. Slide this end into the one-fourth-inch hole to form the perch. Let the glue dry for 12 to 24 hours before hanging the birdhouse.
Drill one-fourth-inch hole in either side of the gourd near the top. Thread a length of wire through it and fashion it into a loop. Hang the birdhouse in the desired area.