Before you go
Open the region list once while you have a connection; after that it is stored on your phone. Remove birds you have already seen many times, or keep them and use the New marker to see which ones would be lifers.
On the trip
Start a fresh copy each day from My lists, so each day is its own checklist with its own date and place. At the end, export each day for eBird, or back up all of them in one file.