Wrens are very small birds, so their houses should have an entry hole of about 1.125" in order to keep larger birds, like sparrows, from taking over the nest or harming the wrens. Our wren houses are specifically designed for these shy and secretive little creatures, with slanted roofs for water shed and a hanging mechanism to keep our feathered friends comfortable and safe. These unique, handmade birdhouses have been designed and created with highly reputable Amish craftsmanship right here in the USA. Every detail of these pieces have been thoughtfully planned out so that you get the best of the best. Each birdhouse is made with Poly Lumber and 100% post-consumer recycled plastic; a wonderful way to take care of the Earth while simultaneously enjoying the Earth's beauty. To ensure no maintenance is needed on these houses, our builder uses stainless steel screws and cables, aluminum screens, and UV protection.