This is the page where you can download all of the data that you've submitted to eBird. The data are downloaded in a spreadsheet that you can store on your personal computer, allowing you to manually backup your eBird data whenever you choose. The file will come as a .zip file so that large amounts of data can be compressed and sent via the Internet. You should be able to open these files using prepackaged software installed on your computer. If you don't have the software it is available here. Once the folder is opened simply double-click on the file to see your data. Use Microsoft Excel or some other software program to work with your data and save it on your home computer.
For more on My eBird, check out the All About: My eBird article.