I listened. I didn't make any noise. It got a little stronger, a little stronger. I tried to figure out what it was--sometimes it had the double-scratch rhythm of a large sparrow...which, at this time of year, would be a spotted towhee. But sometimes it didn't, and towhees, like other sparrows, are fairly regular in their scuff-scuff....scuff-scuff. What else, I wondered. Probably not a raccoon. It was too early for a raccoon to be out, still low sun. Could be an armadillo, though it was a little early in the evening. Not a squirrel, in that particular patch of brush, and anyway, a squirrel would have scolded at least once. Too much sound for mice or wood rats. A snake winding its way through...possible, but not likely. Coachwhips, who like that rocky knoll, move faster and make more noise.
The noise grew closer to the edge of the clump of brush...and there was the noisemaker:
I went up to that area hoping to see the same species of tiger beetle and get more images, but instead a different beetle appeared. Although some beetles cooperate by sitting on a flower or leaf for long enough to change lenses and get a good image, many don't. This one took off running when it saw me (straight at me, in fact) and then, after it went past me, it went down a hole. These are the best two images. The one on the left was lightened, because it was hunkered down (momentarily) behind that dead grass clump, in the shadow.