Abstract Scribbles, the damage caused by mining larvae of the moth Ogmograptis sp. (Bucculatricidae), are a common sight on the trunks of many Eucalyptus species in eastern Australia. They provide a record of larval behaviour that can be easily measured when the trees shed outer bark layers. Measurements were made of scribbles on three species of eucalypt (Eucalyptus racemosa ssp. rossii, E. pauciflora and E. delegatensis) in the Australian Capital Territory. Scribble density varied between tree species and study sites but was consistently higher on the southern and eastern aspects of tree trunks. Some characteristics of mining behaviour, such as initial mining direction, were found to be random, but others including mine length and number of direction changes follow distinct patterns but differ between eucalypt species. It is likely that there is more than one species of Ogmograptis Meyrick as currently described (O. scribula Meyrick, from E. pauciflora) and each eucalypt species may be host to a different species of Ogmograptis.