My early approach to providing bird houses followed traditional wood and box fabricated structures. Now my approach focuses on more natural housing made of tree limbs and logs that have natural decayed centers creating the house cavity. I cut the logs into proper lengths, drill an access hole, and add simple tops and bottoms. The houses are either attached to trees with screws or hung from limbs with wire. My first payoff four years ago was attracting a family of House Wrens (that I had never observed before this time) and Carolina Chickadees that have continued to nest in my yard.