The Pronghorn Rut
When most think of the rut in Colorado, their minds picture bugling, battling, big-boy bull elk; mule deer bucks locking antlers in Greco-Romanesque scuffles; whitetail bucks laser focused on tending to their does; and the NFL-helmet-on-helmet-like crash of bighorn rams. What few picture is the equally impressive battles and behaviors that take place during the pronghorn rut.
Beginning in mid-August, pronghorn bucks will start sizing each other up in preparation for later battles. Having hung out together in small groups during the summer months, the males split apart and begin gathering their harems of three to five does in September. They mark their territories by rubbing their horns and the scent glands beneath their ears and the large black one on the jaw below their eyes on clumps of grass, shrubs and trees. Male pronghorn will also scrape a clear spot on the ground, then urinate and defecate in the center of that spot to mark their domain.
Bucks will protect their harems and territories starting out with grunts and staring contests, then chasing off other males, or engaging in pushing and shoving contests, to all-out battles. Some of the less-dominant bucks (either younger males or bucks that are past their prime) will wander between groups on the lookout for a stray doe and can be seen roaming the edges of another male’s territory waiting for their chance. The constant vigilance, fights and tending to the does makes the rut a stressful time for the bucks.
It’s an equally stressful time for pronghorn does. While most of the focus of the rut tends to be on the males, female pronghorn are very busy, focused and on the move. For many does, a harem is a temporary thing, with individual females staying in the group for a few days to assess a male’s fitness before either mating or breaking off and seeking out other males and opportunities. Pronghorn does choose their bucks and decide who to mate with, and might end up mating with more than one male. Some pronghorn “twins” might actually have different sires.
All this activity makes the pronghorn a bit less wary (and they are normally VERY wary), which is a benefit to both wildlife watchers and hunters.
Breeding activity slows down in late October, and the harems and satellite males begin to merge into larger herds for the remainder of the fall and winter. Although pronghorn can be found in many places in Colorado, the area around Falcon, northeast of Colorado Springs, is a particularly great place to watch pronghorn: Falcon is to pronghorn what Estes Park is to elk.
Wayne D. Lewis is the editor and art director of Colorado Outdoors magazine.