Bill has been a resident of central Florida since 1978, when he and his parents moved from their native Pittsburgh.
He has been birding since age 14 and joined both the American Birding Association (ABA) and Florida Ornithological Society (FOS) in 1984.
He has compiled bird sightings statewide for the FOS Field Observations Committee since 1992 and is a former member of the FOS Records Committee.
For ABA, he serves as chair of the ABA Checklist Committee and a technical reviewer for Birding magazine.
Pranty also serves as editor of the 60 plus Christmas Bird Counts in Florida, started 2 new counts, and is the compiler of three Christmas Bird Counts.
He has contributed more than 275 publications to the ornithological and birding literature, including four books: A Birder's Guide to Florida, 4th and 5th editions (ABA 1996 and 2005), Birds of Florida (Lone Pine Press 2006, co-authored with Kurt Radamaker), and the 7th edition of the ABA Checklist (ABA 2008, co-authored with Jon Dunn and others).
Although not a competitive lister, Bill keeps lists of his participation on Christmas Bird Counts (164) and the number of exotic birds photographed outside of captivity in Florida (63 species).
Bill is considered the authority on the exotic birds of Florida.