There were a total of three shrikes attempting to corner this snake.
Loggerhead shrikes impale their prey on a thorn to eat it. I imagine
that was the plan with this snake. It got away.
In a way, yes, I wait for stuff to happen...but I have to be where stuff is happening so I spend a lot of time looking for places that have the right conditions for making pictures of birds. If you'll notice, there aren't many pictures of perching birds in my galleries; it takes lots of muscle control to hold a big lens steady to photograph little birds. So, I need to be able to brace the lens most of the time. I use a low stool and a tripod and sometimes I put a beanbag on the tripod and rest the camera on th beanbag so I have better ability to track the bird.
In this picture, the juvenile loggerhead shrike had been screeching at the snake and alerting the adults to it...that's what clued me in that something interesting was happening.