In Kansas he worked, under the supervision of Harrison (Bud) Tordoff, on the comparative breeding behavior of Ammodramus sparrows.
He retired in 1999 but continued his field studies as a research associate and head of Archbold Biological Station's Ornithology Laboratory.
[4] All over the world, he gave invited lectures with locations including "Queensland, West Berlin, Oxford, Moscow, Tel-Aviv, Johannesburg, Tokyo, and Haines City".
For the summer of 1972 and beyond, Woolfenden and Fitzpatrick immediately started collaborating on projects involving Florida scrub jays.
Their 406-page book The Florida Scrub Jay: Demography of a Cooperative-breeding Bird was published by Princeton University Press in 1984.
In a letter to Jack P. Hailman, Ernst Mayr called the book “an instant classic.”[2] In 1985 the American Ornithologists' Union made an award of the Brewster Medal jointly to Woolfenden and Fitzpatrick for their long-term study of Florida scrub jays.