General Discussion : Treating the outside of nest box.

Old weathered wood has a rougher surface and is free of toxins. However coatings today are very safe. My local home depot doesn't even sell solvent based coatings anymore. I maintain almost 100 boxes and have waterproofed the exterior on about half. At a few sites the landowners insisted I paint the box to match the barn color. I like to wait a couple seasons till the exterior becomes weathered then waterproof it with a clear sealer. The Kestrels continue using those boxes as always. It's more about the food supply than the coating on the box. Also the boxes last longer. Here in Pennsylvania we have high humidity late summer. Untreated wood doesn't last as long as in areas of low humidity. As always there are exceptions and nuances. But weathercoating has not impacted nest success for me whatsoever.