In San Francisco, coyote dens were abandoned by their occupants long ago — dens are used for birthing and for the first months afterwards before the pups move around much. After that, although coyotes return to the denning area, they sleep out in the open and in various locations. Here are two dens, no longer being used, which I saw on the same outing.
This first one shows an opening which has closed up a bit with debris due to non-usage. It’s a hole dug into the root system of a fallen tree. When it fell, the tree was sawed into pieces and left there. The upended tree left openings through the partly buried root system in the ground which the coyote then dug even further for its use as a den. The landscape it is found in is a small redwood grove, as seen above.
The second den, below, is one which was entirely dug out by animals. It is located in a scrub area which faces a protective forest. It may have been originally built and used by another burrowing animal. When the coyotes found it, they expanded it for their own usage. This den, as opposed to the one above, has an opening that has caved-in and opened up. The opening probably had some kind of foliage hiding it when it was in use. It opens to the top and side of a hill and goes way back, with a ceiling which is about a foot under ground level. We could have found out more about it by destroying the den, but our aim is always to interfere as minimally as possible: hopefully a family will be occupying it next spring!
Every den is different. In urban areas, coyotes have been known to build their dens near buildings, under porches, close to roads and even in parking lots! Last year in San Francisco, one mother had her pups under a parked car in a driveway right off Capp Street at 24th Street, which are busy and noisy streets. This year a coyote gave birth in one of the public restrooms of Golden Gate Park!