The best type of birdhouse (nestbox) is one that is designed with a specific bird species in mind. Different species have preferences relating to opening size, depth of box, etc. For example, if you have chickadees, the house should have an entrance hole with a diameter of 1 1/8", Western Bluebirds 1 1/2", and Mountain Bluebirds 1 9/16". Keep in mind that you will not get bluebirds to nest on your property by putting up a bluebird nestbox unless your area is already bluebird habitat. Choose a birdhouse based on the bird species you see around your yard. Also, remember that not all birds will use a nestbox. Jays, robins, and goldfinches are not cavity nesters. House Finches often prefer to build nests in hanging plants or in the decorative wreaths on your front door.

Birdhouses should be functional as opposed to decorative for the best success. They should have drainage, ventilation, and a way to open the box for cleaning at the end of the season. They should not have perches. Cavity nesting birds do not need perches and the perch often provides an advantage to predators.

Also, very important to a successful birdhouse is placement. Bluebirds prefer boxes placed out in the open and will use the box as a perch to look for insects in the grass around the box. Chickadees, wrens, and nuthatches prefer a more secluded, less visible location. I find that chickadees, wrens and Downy Woodpeckers are very happy with nestboxes attached to a side of my home that has little human traffic to disturb them. A nestbox attached to the side of your house provides good protection from predators, such as neighborhood cats. If you mount a box to a pole or post, you can use a baffle to protect the birds from raccoons and cats. A box attached to a tree can be fitted with a predator guard at the entrance hole. In addition, there are metal plates in the correct entrance diameter that can be installed to keep woodpeckers or squirrels from widening the opening or to reduce the opening size to create a box for a specific species. In other word, if you have a box with a 1 1/2" entrance hole, but you would like it to be used by chickadees, you can attach a plate with a 1 1/8" diameter and you will be good to go.

Remember, birds do not read and often ignore "expert" advice concerning their preferences and behavior.