In addition to the Official Bird Checklist, a Seasonal Bird Checklist was created by Alan Bruner and is updated by Don Gorney. The Seasonal Bird Checklist provides information not found within the Official Bird Checklist. This supplemental checklist contains information about seasonal expectations and it offers tips on the potential significance of seasonal sightings (see the explanatory article below by Alan Bruner).
Indiana's Official Bird Checklist (420 species)
Seasonal Occurrences Bird Checklist (download excel file)
Alan Bruner's Article: originally published in the November 1995 Indiana Audubon Quarterly, describing the Seasonal Occurrences Checklist and how to interpret the codes. Very helpful if you are unfamiliar with the list.