The very large Arctostaphylos here were striking in their growth form...with their fairly-massive old trunks seeming to have "staggered horizontally" over the years while also growing tall and hugging against the large trailside rock outcrop here (which can be clearly discerned by zooming-in on the locator-map in satellite view). The photo was taken from the trail's brushy, steep-dropping edge w/ an iPhone in "pano mode"...but even w/ the wide-angle lens effect I couldn't capture the tops of the plants (which were probably 8+ feet tall). I wish I had gotten a better quality photo and some detail shots of inflorescences, leaves, fruits...but circumstances didn't allow. If I pass again I'll recognize this distinctive manzanita landmark and try to get more detailed diagnostic images.

For the time being, I believe it's A pungens...which (like A. glauca) can grow quite large in the Pinnacles area. Note that this earlier iNat obs of A. pungens appears to be growing near the same spot (against the same rock outcrop).

One of a pair near each other. Flip through the photos to see a series showing the owl calling, then coughing up a pellet. After coughing up the pellet, it appeared to look down at the ground for about 20 seconds.