Remember, if you add North American birds, also add at least one (except Hawaii) state or province to the birds' State Checklist Status so they will appear in the ABA (North America) checklist. Use the StateCL (or Range) button.
(If your guide is older than Version 4.5, you are reminded that there is a renumber facility, Utils | Renumber Master Checklist, to instantly add space between species if you need it as you are adding species. See the update documentation.)