A birdhouse design, which will allow easy access to the inside, is a must for nest inspection and maintenance. A side or front panel that swings up is best. Do not add a perch to the birdhouse. These are not necessary. Cavity nesting birds have strong feet.
Perches only give easy access to other birds such as starlings.
Scoring the inside of the front panel will give emerging birds an easier way to exit the birdhouse. The floor of the birdhouse should be recessed from the front of the box so that it is not exposed to any rain. Ventilation holes near the top roof section are a good idea in summer. They can be plugged with putty in the winter. Finally, predator protection in the form of a baffle increases nesting success.