Other birds prefer single-family homes on well-wooded plots. A corrugated metal roof shields this narrow nest box—designed to simulate tree cavities, which are the preferred nesting spot for many types of wrens and chickadees. The artfully twisted strand of twigs provides camouflage and a place to perch in the dappled sunlight. In fact, a small supply of twigs about 3 inches long will aid wrens in nest building. It's best to place several houses in the immediate vicinity as a male wren typically builds several nests for his female companion to choose from.