Predator Free Rakiura will this month begin investigating whether there is an established mouse population on the island.
Understanding whether mice are already present on Rakiura is an important piece of the puzzle which will help inform PFR’s early eradication and biosecurity planning.
They are often said to be absent because they’re likely to be outcompeted or predated by the three species of rat and feral cats on Rakiura.
However, it is possible the rodents are present in low numbers and have avoided detection. We need to make sure that if we eradicate feral cats and rats, we don't then allow for an explosion in the mouse population, creating a new problem for our taonga species.
Mice compete with our native birds by eating many of the same foods, and are direct predators of insects and other inverterbrates. They've even been known to eat bird chicks.
Predator Free Rakiura is working with NZ-based Wilderlab to undertake eDNA water sampling: our team will collect water samples which will be sent to Wilderlab for testing for traces of mouse DNA. Our initial focus will be around the township of Oban as this is a likely area for mice to be living, given the presence of buildings, freight, human activity, food stores and being one of the main arrival points.
Environmental DNA (eDNA) is a relatively new tool in conservation management. Its potential to facilitate survey and biosecurity work is huge. By testing soil or water samples for traces of DNA, we can understand whether a certain species has lived in or travelled through the area.
The first round of sampling will be the first building block, it won't be conclusive by itself. More work will need to be done to build a reliable understanding of mouse presence, if any.
To find out more about the Mouse eDNA work, check out this Q&A sheet here.
Have another question? Contact us on firstname.lastname@example.org