So you've started using eBird Mobile, either for the first time or on a new device, and you don't see any lists from your previous eBirding endeavors. Do not worry—no lists are missing or lost! As of right now, eBird checklists are not 'synced' between eBird Mobile and the eBird.org interface, nor between versions of eBird Mobile.
This is due to the current way that the upload process works: the app is actually creating a .csv file from what you enter, and is uploading this to the website. As a result, there is no easy way to 'sync' the data back to the app, from this one-way street of uploading.
We are planning to update the way that this works in coming months, and at that time we'll be able to move towards having your lists appear everywhere that you can enter data. For the moment, if you go to My eBird on eBird.org, you'll be all set!
The most important part of eBird data entry does sync at this time: all of your locations. This, combined with your user information, allows the data entry experience to be quick and easy. We will also be working to enable addition of extra metadata in the upload process in the coming months: breeding codes, portal-specific entries, additional protocols, age/sex information, and eventually photos.