This is an owl pellet.
The owl will regurgitate the undigestible parts of the rodent it swallowed whole.
I found this water hole in the middle of the desert.
It was part natural and part enhanced by man. There was some mining activity nearby so that is probably the ones who did the little bit of cement work.
Now it is a valuable water source for the animals in the area, including this butterfly.
Unfortunately in the summer it will be a dried up and that is when the animals need it the most.
The end of the trail for somebody.
Maybe they needed that water hole.