Before you can start making your birdhouse, you’ll need to fully dry, or cure, the gourd, so that the exterior is hard and then interior can be cleaned out. This can be done during the winter.
Once your gourd is fully cured, you can begin making your birdhouse by drilling the opening doorway. The size will depend on the size of your gourd. I used a 1 3/8 drill bit for mine. Eyeball the placement so that it is where the bottom bulb of the gourd begins to curve upward.
It helps to brace the gourd against something, so it doesn’t roll. Hold the gourd and the drill firmly, but you don’t need to use heavy pressure. The gourds are usually the consistency of thin plasterboard.