We do not like to cut and paste other peoples work on this site unless we have permission in order to give credit [ and it unethical and illeagal.] So until we can get some various bird boxes made ourselves then please visit any of the bird charities who will probably have plans available for you to copy. One such site is here. It is important  not to use preservatives of any kind especially if you are using scrap wood as these can be made again when they drop apart in 10 years or so. If you do use these plans why not make an online donation to the trust to say thank you ( top left corner of menu)..