Luck favors the prepared. That's really what it boils down to, but I still consider this shot to be pretty lucky.
Rocky Mountain Arsenal National Wildlife Refuge is 15000 acres of reclaimed land in the middle of Denver, where the U.S. Army used to make chemical weapons and private industry used to make pesticides. After a massive clean up effort, the land today is home to over 300 species of birds and mammals. This includes a herd of 60-80 bison that live behind a double enclosure of approximately 2200 acres.
The bison enclosure is drivable, with the road extending for a half mile or so. This guy and his buddy were no more than ten feet from the road grazing. There were four cars watching them and taking photographs (you're not allowed to get out of your vehicle for obvious safety reasons. These are wild animals.). Anyway, the four of us were all parked on the side of the road doing our thing, and then when one or the other bison moved, somebody would choose to drive up the road a little ways, turn around and come back for more. There isn't a whole lot of traffic. We did this for maybe 20 minutes or so.
For this shot, I was the only one watching this particular bison. The other three cars were with the other guy. I was experimenting with different crops on my lens, when all of a sudden he lifted up one of those massive hooves and started scratching his face like a dog. As I had the camera on burst mode, I hit the shutter and fired off as many shots as I could, praying that in my excitement one of them would be in focus with a tack-sharp eye. None of the other cars saw him do it, I was alone. Like any good itch, it lasted for maybe ten seconds. Pure awesomeness. After that, I left to race home and see what I had. Yep, I got lucky…It was a great day. And this is one of my very favorite images I have ever made.