The diameter of the entrance hole is very important.
Most birds also prefer the color of natural wood.
A way to clean out the box - One side of the box should be able to be opened so that old nesting materials can be cleaned out each winter. Overhang - The roof should overhang the entrance hole to provide protection from rain and sun. A perch actually encourages use of the house by invasive species. Where a birdhouse is mounted is especially important. In addition to being the right dimensions, a birdhouse needs to be hung in the right habitat and at the correct height if it is going to be used by the species it was intended for.