 One of her main achievements with the RAOU was the instigation, leadership and successful conclusion of the RAOU's first Atlas of Australian Birds project, fieldwork for which ran from 1 January 1977 to 31 December 1981.Reilly was actively involved in ornithological fieldwork for many years, especially in studies of little penguins.In 1968 she founded the Penguin Study Group of the Victorian Ornithological Research Group.