These small birdhouses have detachable lids in case the owner wishes to hang them outside for use by a feathered tenant.  They are designed for the smaller birds such as wrens, but since each has an indoor finish they may be best suited for the protection offered by the atmosphere inside a house, away from the sunlight, moisture, and other things that erode man-made products.  If you like the gray, weathered look of barns and fence-posts, your birdhouse should be hung outside where it will quickly take on a similar appearance.  Mesquite is a long-lived wood that should not decay for many years.