Birdhouse Boulevard is a wheel-chair accessible trail lined with birdhouses. Carter also designed birdhouses, clocks, totems, and metal sculptures. The trail has 40 birdhouses to attract tree swallows and bluebirds. As well as some decorative pieces including castles, birdhouses, pet dishes, etc. Juniper titmice will sleep in cavities, dense foliage, or birdhouses. Tapes of purple martin song are sold to attract martins to newly established birdhouses. The oak titmouse will sleep in cavities, dense foliage or birdhouses. Other species seek out crevices, using buildings or birdhouses when tree holes are not available. This campsite has many small sleeping cabins that are called "birdhouses". Meanwhile, Steve and Roger build birdhouses for cash. Russell also built two birdhouses against the exterior of the eastern wall. In 2015, students helped build and develop solar-powered birdhouses. Bitters took this knowledge with him when he later joined Hans Sumpf and produce birdhouses.