Soaking up some September sun, I was perched on a rocky outcrop of Wild Horse Island in Flathead Lake. The sweet vanilla scent of Ponderosa pine permeated the air as I watched gulls flying overhead. I sat quietly on a large boulder and waited for the residents of this island ecosystem to resume activity as if I were not there. Across the small gully on the next rocky hilltop, a single female deer grazed in the shade of a pine. By the black tip on the end of her tail, I was able to identify her as a mule deer, Odocoileus hemionus.
After an hour of watching the doe, a buck appeared in the trees on the knoll below her. Hesitantly, he came out of the protection of the forest and into the meadow. His large ears moved independently like radar detectors as he listened for any sign of danger. Satisfied the meadow was reasonably safe, he advanced and a procession of five bucks emerged. Usually solitary, the males had banded up for the rut, or mating season, which peaks in September and October. Three of the deer had large racks with four-point antlers on either side of their heads. The other two were yearlings and their antlers consisted of two points on each antler in the form of a “Y.” The large buck led the herd toward the center of the meadow to a tree with shade suitable to escape the strong sun of Indian summer. Lowering his head to the ground he began to graze, intent on eating the grasses and forbs that would provide energy to sustain him through the rut and upcoming winter.
Wanting a closer look, I crawled on my hands and knees across the gully toward a rock to hide behind. With their keen senses, the deer noticed me moving toward them and lifted their heads from their afternoon feast. One of the males was alarmed and with a stiff-legged bounce where all four hooves leave the ground at the same time, he moved a bit and then looked back to see if I would follow. Alerted by the raised tail and white rump of the bounding deer, the other males raised their heads. Satisfied that I was not a direct threat, they continued to graze.
During the rut, male deer are consumed with demonstrating dominance, establishing a territory, and protecting a herd of does. I witnessed some of this behavior as one of the bucks lowered his head toward the earth, extended his neck with mouth pointing toward his chest, and positioned his antlers in a sparring posture. Another buck accepted the challenge and assumed the posture as well. They advance toward each other and clashed — the sound of their antlers locking was clear in the still air. The dominant male of the group then moved into position and challenged this winner, pursuing him until he backed away in defeat. In regal form the dominant buck held his head high, antlers extending over his back.
If there had been a herd of does present, this deer would surely have won the right to mate with the females. Less dominant males remain on the periphery of the herd, attempting to mate with does whenever the dominant buck is distracted. A doe will allow a male to mate with her when she is in heat, which is a 24-hour period.
Time passed and one by one the deer lay down on the grass, each ruminating and digesting its food. I moved quietly downhill, feeling lucky to have witnessed the ritualistic mating displays of these mule deer.
'Field Notes' is produced by the Montana Natural History Center.