Very little is known about the pebble-mound mouse and the Pilbara species was only described 40 or so years ago. I don't think that is one but cute little guy just the same. A few years ago I was lucky enough to prospect in an area that had active mounds and I was intrigued to discover how they built their mounds. I noticed some pebbles on a young, small spinifex plant, only 6 inches or so in diameter with soft green spines. This was about 5 m from an active mound and there is no way those pebbles got there by themselves. There were also a few pebbles on other plants that looked like tests, but there was one plant in particular that had quite a pile. By putting the pebbles on the spinifex it flattens and bends the spines so they are curved downwards producing a small cavity. I think this is the start of the mound and they burrow and built from there. I had to leave and intended to return to see what happened but other stuff got in the way so never made it back to test my theory.
Around Meeka you might notice the odd random hole that is easily mistaken for a dig hole but is made by an animal. Sometimes there are patches of them. Often under/around a mulga. Obviously a lot of work but what was it chasing that would make the effort worthwhile? It took me ages to work out what was going on there. I reckon they are made by Bungarras digging up trapdoor spiders. I came across one where the Bungarra had made a perfect excavation and split the tunnel leaving half the silken tube in the face.
Don't take the above as gospel, they are just conclusions based on my observations. Keeping your eyes open when you are prospecting and thinking about what you see is rewarding in more ways than one.