You may be interested in having a bird house just for decoration, or you may be trying to attract certain types of birds. However, 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, liveonce bird house 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. Ivonne gives you exact entrance holes and attractive designs