I had the opportunity to see what lies behind the doors of an ANU captive breeding facility. I found hundreds of small, brown, cute eyed creatures.
Kiarrah, a PhD student from the Australian National University is studying the reintroduction of the New Holland mouse to Mulligans Flat Woodland Sanctuary. But first, she needs a population to release. With permission from the NSW and ACT governments, as well as ANU animal ethics approval, wild New Holland mice were captured on the NSW Central Coast and have been bred in the facility, which now houses over 200 mice. Each mouse has an individual enclosure, with some kept in pairs or threes. These enclosures are modified plastic tubs with red colouring on the sides. The mice can’t see red so to them the world outside appears dark which reduces their stress level. There is a metal barred lid for each enclosure and inside is a mixture of bedding and nesting material, food, and boxes to hide in.
The enclosures are stacked on shelves around the room. Everyone entering has to don a pair of blue plastic booties as they step over the threshold to reduce the risk of disease spreading to the colony. This is possibly the only captive bred population of this threatened species in Australia, so ensuring their health is the ultimate goal. All the mice are so quiet that on stepping into the room you wouldn’t know there were over two-hundred animals with you. These mice also lack the distinctive ‘mousy’ smell of the more familiar introduced house mice. Peering into the nearest enclosure I spot…nothing. The mouse is most likely buried under its nesting material, using its natural instinct to burrow. I continue looking along the shelf until I finally get my first glimpse of a New Holland mouse. It is ridiculously cute, more like a cartoon mouse than a real one with large ears, big black eyes and a face full of whiskers.
Kiarrah showed me how she visually assesses the health of the mice. She also tipped out a pile of the radio tracking collars she was preparing to attach to the first release group. These were very small, as you can imagine a mouse’s neck is quite tiny under all that fur! Once Kiarrah has collared some mice and tested the effectiveness of the collars the reintroduction can begin. A reintroduction study involves releasing a captive bred population of a threatened species back into its natural habitat, where it no longer exists. These studies are important conservation biology tools, providing information on population ecology in a variety of habitats and overall reintroduction success. This information is essential for managing the long term conservation of a threatened species, informing further reintroductions and setting up insurance populations.
These aren’t the first mice on the loose. A reintroduction of New Holland mice occurred at Mulligans Flat Woodland Sanctuary in 2013, with further information needed to understand the full role of this species in the ecosystem. This native rodent has been extinct in the ACT since the 1880’s. It is believed this species once had a single continuous population on mainland Australia but this is now fragmented across areas of NSW, Victoria, Queensland and Tasmania. The species is decreasing in number and is listed on the IUCN red list as vulnerable. All the usual suspects have been linked to their decline including pest species, changed fire regimes, habitat loss and, the big one, climate change. To safeguard this species from extinction we need to learn a lot more about it and its role in the ecosystem to inform conservation actions. Kiarrah’s project is funded by an Australian Research Council linkage grant and the Ecological Society of Australia Holsworth Wildlife Research Endowment, and is a partnership between ANU, ACT Government, the Woodlands and Wetlands Trust and James Cook University. The project is an important step forward in securing the future of one of Australia’s threatened mammal species. We can’t wait to follow along with her research as she learns more about the adorable New Holland mouse.