What should a purple martin birdhouse be made of?

A purple martin birdhouse should ideally be made of durable materials such as wood or high-quality PVC. Wood provides natural insulation and a traditional aesthetic, while PVC is weather-resistant and easy to clean. It's important that the birdhouse has proper drainage and ventilation to keep the interior dry and comfortable for the birds. Additionally, using non-toxic finishes can ensure the safety of the purple martins.