How does Colleen McCullough use imagery in The Thorn Birds?

The focus of McCullough's work is in painting an accurate description of live on a sheep station near Gillanbone, New South Wales. McCullough thoroughly details the sulfuric smell of the bore head, the annoyance of flies and dust, as well as the numerous gates that must be opened and closed manually to travel by car or buggy from Gillanbone to Drogheda, the Cleary's ranch.