Desert Mouse (Pseudomys desertor) Delicate Mouse (P. delicatulus)

What do they look like? The Desert Mouse grows to approximately 10 cm, with a tail about the same length. Dark brown to reddish-brown with a faint, but distinct orange-brown eye ring. The Delicate Mouse is small, about 5 cm long, with tail longer than the body. Its body and tail are distinctly 2-toned – buff on top, cream to white below.

Where do they live? Desert Mice are largely confined to Desert Upland parts of the region where mature spinifex or other thick, native grass cover occurs. Delicate Mice are widespread and less habitat specific, although they seem to prefer sandy soils. Both species are common in suitable habitats..

What do they need to live, eat and breed? Desert Mice require thick ground cover to persist. They prefer long unburnt spinifex country. Delicate Mice on the other hand occur in a wide range of habitats and generally those recently burnt or of low cover. Both species feed on seeds, leaves and stems of grasses, sedges and herbs.

When might I see (or hear) them? Both are rarely encountered. Small mice found around station infrastructure are usually the introduced House Mouse, which look similar. Desert Mice may undergo rapid population expansions to fill habitat as it becomes available after good rain, but there must be sufficient ground cover.

What management actions affect this species? In long-unburnt country, the Desert Mouse is more abundant, and the Delicate Mouse is uncommon. Conversely, when the country burns, Desert Mouse numbers decline, and the Delicate Mouse breeds. This is due to their body size and habitat preference. A small-bodied mouse can shelter from predators more easily in burnt habitat than a large mouse. The Delicate Mouse also loves fresh seedling forbs and annual grasses. Conversely, the larger Desert Mouse needs dense cover for shelter, and has a diet of seeds, leaves and young shoots. Small mosaic fires that leave refuges of dense habitat will maintain habitat for both species. Spelling after burning to allow grass recovery, is important in retaining habitat patches for these two mice.

How do they benefit the land I manage? Being seed and vegetation feeders these mice help cycle nutrients in vegetation and disperse seeds. Native mice are eaten by a wide variety of other animals, especially snakes and nocturnal birds, such as owls and frogmouths. By allowing these predators to persist, there are species in the landscape ready to feed on unwelcome introduced rodents that can occur in plague proportions.

Similar species: House Mouse (Mus musculus), Eastern Chestnut Mouse (Pseudomys gracilicaudatus), Pebble-mound Mouse (Pseudomys patrius).