What type of wildlife could be digging these holes in my yard?

[Wonderment]

My mother just moved in to a mountainous area in Colorado and we were hoping someone could tell us where these lil' holes are coming from!

They don't have dirt near them, they look like someone just stuck a hallow pole into the ground! They are amazing, absolutely perfect looking and about 2.5 inches in diameter. I don't know much about wildlife, and was hoping someone who did could give us some ideas of what is welcoming us to the neighborhood.

Thanks!

 

[formerly_bob]

It's probably some type of ground squirrel such as the 13-lined grounds squirrel.

 

[table tennis]

its u when u sleepwalk at night
LOL