The Bush Rat is a small omnivorous rodent found across Australia in woodland areas. Nocturnal and elusive, their numbers continue to decline due to feral predator predation and habitat loss. AWC has successfully restored the locally-extinct species back to North Head Sanctuary, where they now outnumber invasive black rats.
Between 2014 and 2016, AWC successfully reintroduced 170 Bush Rats to Sydney’s North Head Sanctuary, with the goal of establishing a self-sustaining population. The reintroduction program was part of a unique initiative to use native wildlife to outcompete a foreign species (invasive black rats) and act as a biological control.
This program was an enormous success. Surveys indicate that the population of black rats at North Head has decreased from an estimated 112 in 2019 to 29 in 2020. The decline continued in May 2021, when only nine black rats were captured during a survey of 250 hectares at the sanctuary.
The reestablishment of the locally-extinct Bush Rat (and their ecological processes) is helping to restore Sydney’s lost biodiversity.
One of the biggest threats to the Bush Rat is predation by introduced foxes and cats. Evidence suggests that the incidence of fire can increase predation of Bush Rats due to the removal of undergrowth in which they are usually able to hide.
Bush Rats may also be pushed out of their territories by the larger invasive black rat, which it competes with for food and habitat.
Measuring about 16cm in length, Bush Rats have soft grey-brown fur and pink-grey feet. Their trails are brown to black, almost free of hair, the same length or slightly shorter than their bodies. Unlike Black Rats, the Bush Rat has more of a rounded head and a blunt shaped nose, with chisel-shaped front teeth. Bush Rats may weigh between 65g to 225g, with males being slightly larger than females.
Bush Rats are rarely seen due to dense habitat in which they live, and their shy and solitary nature. They are nocturnal and shelter during the day in short burrows or grass-lined nests under logs or rocks. They are territorial, but during spring and summer time travel great distances to forage and mate, with males covering distances of up to a kilometre each night.
In the warmer months Bush Rats consume primarily seeds, arthropods and fruit, and individuals have been observed feeding on nectar without damaging the blossoms. During the cooler months their diet consists more of fungi and fibrous plant material.
Breeding season for the Bush Rat begins around November, with gestation lasting approximately 22 days. Females usually birth 4-5 young in a litter. Once old enough, at about 25 days, the young rats leave their nursery burrow to establish a territory of their own.
Range and Abundance
One of the most common native rodents on the continent, Bush Rats have a range extending across coastal NSW, VIC, SA, WA and parts of QLD. Their preferred habitat is woodland, forest, and heath with dense undergrowth, rocks and logs for shelter and nest building. Bush Rats are not good climbers and unlikely to persist in urban areas.
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