A writer and illustrator, Thyrza Davey graduated from the SA School of Arts in 1948. She had always been keen on horses, so her first job was as an illustrator on the SA magazine, Hoofs and Horns. During this time she visited the Northern Territory and Papua New Guinea. She travelled extensively throughout South Africa and Central Africa in the 1950s. She moved from SA to Queensland in 1957 and remained there for 23 years, working as an artist for most of that time. She moved around Queensland, living at Brisbane, Townsville, Nambour and Yeppoon, and had many small showings, along with pottery which she was doing as well. One major show of paintings was at John Cooper's 8 Bells Gallery on the Gold Coast. In the 1970s she toured Europe, visiting many galleries.
She moved back to SA in 1979 and went to live in the Barossa Valley to paint the countryside and the life style of the German people. She began writing in 1980 in the Barossa Valley, but continued to paint when not involved with a book. She had a second major exhibition of paintings at the Barry Newton Gallery, Adelaide, in conjunction with the launch of her book, Barossa and Beyond (1988), depicting the Barossa Valley in art. She lives alone, and her interests include gardening, restoring old cottage, and antiques.