When I fired, the buck tumbled from knife’s-edge basalt onto a moonscape of rubble. The season before, I’d dropped a deer just below, in scree devoid of anything with roots. My friend Vern had killed a huge buck nearby, in a bed of dust wallowed deep by generations of mule deer.

After we routinely found bucks well above forest and meadow, I looked closer. Tiny rivulets trickled from snow patches that shrank slowly throughout the summer. Alpine deer nibbled succulent shoots in shaded nooks irrigated by this melt as forage below turned yellow and rank.

One riddle solved. But why did so many dawn kills happen on this high east face? Midday and later, we took deer all around the hill. In a fit of logic, we started squaring where we saw deer with the time of day and weather conditions. On hot afternoons, bucks sneaked around to shaded north sides. Arctic fronts pushed them onto the south slopes. But on October’s opening mornings, the frost yielded first on the sunrise side of rocks, and the old bucks we sought warmed themselves there. Routinely killing them was simply a matter of understanding where their instincts would lead them.

For more opening day tactics, click here.