We set 10,000 traps in search of a rare native mouse. Here’s what we found

It is 5am when we crawl out of our tents. The catbirds are calling and the night sky is fading to dawn as we prepare to head into the bush. We're surrounded by the towering eucalypts of southeast Queensland in search of a small, native mouse called the pookila. Also known as the New Holland mouse (Pseudomys novaehollandiae), the pookila is about the size of a small chocolate bar, weighing less than 20 grams. These mice spend their nights foraging for seeds and fungi, and their days tucked away in a burrow. The pookila's preferred habitat in Queensland remains unclear, though they can be found in patches along the east coast of Australia, from Queensland down to New South Wales, Victoria and Flinders Island in Tasmania. However, this little mouse faces mounting pressures from habitat destruction, climate change and predators, among other factors. These threats have led to declines and local extinctions in southern pookila populations. In the past, pookila have been found incidentally at ten locations in southeast Queensland. Many of these surveys, however, were conducted several years ago and were not solely focused on searching for pookila. For their new study, researchers visited most of these sites over a 31-month period to gain a better understanding of how pookila are living and what threats they face. To find the elusive pookila, the team revisited seven locations west of Brisbane in southeast Queensland where the mice had been previously found. At each site, they stayed for four to five nights at a time. Over the course of nearly three years, they set a total of 10,666 traps. Each afternoon, they deployed box traps with peanut butter balls, commonly used to attract small mammals, and selected suitable spots where native rodents might be found. They covered each trap with leaf litter and placed a peanut butter ball inside. The next morning, they returned to check the traps, hoping to catch some mice. Some days, the rodents were plentiful. Other days, there were none in sight. The work took place in all kinds of weather, from sunny afternoons to drenching rains. On particularly wet mornings, the team would trudge back to their tents, soaked and exhausted. Occasionally, cheeky possums located their peanut butter stash and stole the bait directly from the traps. This often brought smiles, or tears, to the researchers. They repeated this process of setting and checking traps over 31 months in search of a tiny native mouse. During that time, they only managed to capture a single pookila. They measured the rodent, including a juvenile bush rat, to help determine its species. It is difficult to ascertain exactly what happened to Queensland’s pookila population. Since 1996, only around 125 of these mice have been captured in Queensland. As such, there is currently insufficient data to fully understand how the species has fared over time. The findings suggest that pookila may be experiencing local declines in Queensland. These mice may also be becoming harder to find due to shrinking or shifting populations. Queensland’s pookila could also be facing similar threats to their southern counterparts, including habitat destruction and climate change. It may even be a combination of all these factors. In any case, the results raise serious concerns about the pookila’s long-term survival in both Queensland and across the country. Continued monitoring is therefore essential. Resurveying study sites and other locations across Queensland will help track any trends in the species' status.