Can I used recycled materials to build a nest box?

When providing nest boxes for birds, it is best to mimic their natural cavity as best as we can. That means using untreated and unpainted wood, ensuring there is proper ventilation and drainage, and sometimes choosing proper entrance hole sizes. Though using recycled materials is a good idea in theory, we do not recommend using them for bird houses for several reasons:

• Thin materials like recycled plastic jugs, cardboard cartons, and other similar items do not regulate temperatures well. Many plastic and metal houses, or even thin wooden houses (like decorative ones made of balsa wood) are thin and can either heat up too much or will not keep the birds warm enough in cold spring weather. Wood that is around ¾” thick (sold as “1” thick boards) is ideal because it can insulate against most temperatures. Though, it’s good to keep in mind that nothing is immune to the very extremes.
• Many recycled materials are flimsy, and have tendency to break or fall apart. Plastic can bend and change shape, and cardboard or other paper-based materials can disintegrate in wet weather. If there were strong winds or rain, that structure may not hold up.
• When recycling wood from a different project, consider how that wood was used and what it was treated with. For example, you would want to check that it is the proper dimensions and thickness, that the wood was not pressure-treated for insects or fungi, and that it is not painted or stained.
• It’s important to consider what the recycled materials are made of, what they once contained, and how those materials may affect the delicate nestlings. Fumes, harmful chemicals, and residues can often remain for long periods of time. This is also why we do not recommend using wood that has been treated with fungicides, pesticides, or other chemicals that are designed to prevent structural damage.

We created a helpful webpage with Features of a Good Birdhouse here which offers general tips for nest boxes, and we have our Right Bird, Right House tool here, which also has species-specific tips on how to build and install the box. Even if you don’t plan to build a box, these links may help you whittle down your buying choices.