A unique habit.

Unlike most wildlife that deposit their #2s randomly, wombats will carefully place it on top of something, in this case a rock. I use this particular rock for propping open a gate - I clean the top every couple of days but it will always be redecorated next day. When a wombat gets in the tractor shed, I can find the chainsaw, shovels, motorcycle wheels or even my boots neatly festooned.
A quaint habit indeed!