We received this photograph from Jon Anda, who asked for help in identifying what was digging holes in and under rotting pine stumps at his place near Motueka.
We identified the culprit as being one or more Norway rats, as the clues fitted. Norway rats dig burrows of 60-90 mm in diameter underneath rocks or tree roots, alongside buildings or in the banks of watercourses. Piles of soil, such as that pictured here, can remain around the burrow entrance. Sometimes bits of inedible food might be seen around the entrance, having been discarded from a food store in the burrow. In this instance, huhu bug carcases were found nearby.
As we had no illustration of Norway rat burrows, Jon was kind enough to let us use his photo in our dens category under 'Footprints and Tracks' clues. Jon is otherwise known as Johhny Prepper and the Weka called Jeffery III on Facebook.