We used 1x4s for the doors to access the nesting boxes. We considered using galvanized tin surrounded by a wooden frame, but in the end decided to use up the wood we pressure washed. We used two door hinges to hang these doors up. They turned out really nice! Because they are solid wood, they are sort of heavy but the weight will be a plus because the wind will not be able to blow the doors at all.
Once we had everything built, we caulked all the gaps in the wood and routed all edges. Aaron chose to use the router on all corners and edges so that the wood has less of a chance to rot.