Whenever I go out to the fields in the west valley, I look for the highest perch that the birds of prey will roost on and sometimes mark as their territory. At the bottom of that perch (in this case a very tall power pole), you find their feeding leftovers. There are balls of regurgitated hides of eaten field mice, gophers, wings of smaller birds, bones that were not digestible, especially small skulls.
What exactly is my fascination with this, I am not certain, but think it is because I am trying to figure out what was the meal of the day.
I also have a collection of larger skulls I have found in my recent travels, from cattle to coyote, to rabbits, to mice. Sometimes it is just a jaw bone. I have them on my patio and one day I may make a mobile out of them. Someday soon.