We had driven about halfway through the buffalo area of the park and only seen them at a distance through some bushes. Fiona had seen the flag at Mahoney off in the distance, and Ingrid was telling Fiona about the place. Suddenly, one of us realized that there were a half dozen buffalo coming over the ridge behind us at a good clip. As luck would have it, their (well-trod, now that we recognized it) path passed just a yard or so behind the car.
We didn't get a picture of that group, but when another half dozen came by a minute later at a somewhat more dignified pace, we got a few photos. This buffalo was dark enough that he might as well be a sillouette against the grey sky and brown ground.