They'll use small caves. I found them in rock pits here in NM, where there is a crevice between the rocks. They dig in from there. Also, in this flat country, we investigate any pile of rock or dirt that just stands out. Sometimes it's just gopher mounds, sometimes in an excavated coyote den. We've found 27 dens on the ranch behind my house, like that.
I feel that most coyote dens are ones that they've taken over from badger holes, groundhog holes, and the like.
Good solid advice from Dog1whckr and Kirby.
Tony
