Man with No name- Finding Bandera's Place

He raised the glass to search the top of the cliffs. The only sign of life was a lone vulture, soaring hopefully above the massive ramparts of rock.

The ugly bird swam into the field of his glass, then slid away as the glass swung on. Suddenly the glass whipped back to focus on the wheeling vulture. The hunter’s jaw dropped as he sucked in a deep, gasping breath. There was no mistake about it. The image of the big bird shimmered. Unlike its normal majestic flight, it seemed to dance in the air and even multiply itself for brief moments.

Swearing under his breath, the bounty hunter sprang to his feet. He snatched the coffee pot aside and began to kick the smoky fire apart, stamping on the burning embers, emptying the half-brewed coffee on the larger pieces.
...

“Oh, aren’t we just too smart, big-brain? And by the way, how did you find this place when sheriffs’ posses have been hunting it for years?”

“Simple, my good man. A vulture told me.”

“Okay, okay. Ask a stupid question, get a stupid answer.”

“With that stiff-necked attitude, it’s no wonder they don’t tell you things they do me. I just happened to notice a vulture wheeling high over the cliff and suddenly it shimmered.”

“Shimmered? Are you nuts or is this supposed to be a joke?”

“Shimmered,” the hunter said firmly, “and it’s no joke. You know how heat waves make everything dance and shimmer over a desert. This was much too high up for natural heat waves to reach, so it had to be some intense source of heat causing it. I’d just had a run-in with one of Bandera’s apes dolled up in a full suit of armor and carrying a steel shield that turned my bullets off as if they’d been rain drops. So my first thought was I was seeing heat waves from a superheated steel furnace. I fixed a landmark in my mind and headed that way, and here I am, lucky you.”

- Blood for a Dirty Dollar, chapters 16 and 21