The bulk of the collection consists of the original manuscript notes and sketches collected by Gould for his book The Birds of Australia. Each folder (or notebook) has the name of the order or tribe written on the outside, and inside the folder the notes are divided by species. At the top of each sheet there is an illustration of the bird in question, of which some are lithographs from Gould's earlier work A Synopsis of the Birds of Australia and the Adjacent Islands (1837), while others are original watercolour paintings by Gould. In the margin are headings probably written by his secretary, Edward Prince, such as Latin name, English name, diet and locality inhabited, with manuscript notes and occasional rough sketches by Gould.