You may be interested in having a bird house just for decoration, or you may be trying to attract certain types of birds. If you want to attract a specific species, in most cases, you will need to build or buy a specific type of bird house. For example, Purple Martins nest in colonies and Robins nest on platforms without roofs. Most bird houses are square or rectangular and feature an entrance hole, keep in mind the size of the box and the size of the entrance hole will attract certain species.
Here are some types of bird houses that specific species nest in.
Bluebird houses are quite simple, with a small entrance hole and large roof for extra protection. Bluebirds’ boxes are commonly taken over by other small birds like House Sparrows, and because their population is declining, it is important to include a cone-shaped predator guide and monitor the activity around the nest box.
(Picture by Memotions)
Purple Martins nest in colonies, so their bird houses are very different. Depending on how many you want to attract, you must build them in multiple levels. These bird houses are usually rounded, and should feature a protective roof as well. You can also simply hang several gourds in a cluster. This will help your chances of hosting some Purple Martins!
(Picture by bgottsab)
To attract Wrens, the most important aspect of the bird house is the hole. Make sure the diameter is 1 1/4” which is large enough for all types of Wrens and Black-Capped Chickadees to use, but too small for House Sparrows. Tree Swallows will also use this type of house.
(Picture by donjd2)
If you would like to watch Robins, Barn Swallows or Phoebes nesting, you won’t need a bird house. These birds nest on shelves or ledges. However, you can still attract them by building a platform yourself. All you need is a floor with a little border around it and a back piece for attaching it to your porch or under an eave. Blue Jays, Mourning Doves and Cardinals like me will also use nesting platforms. If you find a nest around your house, try not to disturb it. Moving it can be illegal, as some species of birds are protected by law. Birds will not abandon the nest if you touch it, but if they see you getting too close, they may leave eggs that aren’t hatched.
(Photo by bagaball)
If you are interested in building your own bird houses, here is a useful chart outlining floor size, box height, height above the ground and entrance hole diameter sizes for different species. Goodluck and happy birding!