Artificial nests and eggs have become popular and useful tools for studying nest predation on birds. In particular, they may assist in the identification of nest predators. However, quail eggs commonly used in many nest-predation studies may exclude the detection of predation by small-mouthed mammals, which may not be able to break the eggshells as readily as eggs of small passerines. In this study captive Brown Antechinus (Antechinus stuartii) were given Japanese Quail eggs. They failed to break the shell, although they consumed the egg's contents if the shell had been broken for them. Field trials were conducted in a large woodland fragment on the New England Tableland, New South Wales, using clay and quail eggs to identify predators. Pied Currawongs (Strepera graculina), and possibly other birds, were found to be the most significant nest predators. Mammals were judged to play a comparatively small role. However, we detected large imprints in one modelling clay egg, which corresponded with Koala (Phascolarctos cinereus) incisors. In addition, we report that clay eggs soften at high temperatures, which may affect the size of a predator's imprint, and therefore cause its misidentification.