Life on the Rocks: A Portrait of the American Mountain Goat

Chapter Four: Rewards and Risks

Rewards and Risks DOI: 10.5876_9781607322924.c004 CHAPTER FOUR A life spent living on ledges and peaks comes with both rewards and risks. Few other hoofed mammals spend significant time where the mountain goat roams, finding life easier on more forgiving terrain. During my observations I found that only mule deer and more rarely elk shared the Bitterroot haunts of mountain goats. In other goat ranges, mountain sheep also overlap their distribution and may vie for forage. But of all North America’s large herbivores, the mountain goat and musk ox exist most freely from interspecific competition for food and space—a reward of sorts of their desolate domains. Likewise, most predators lack the tenacity or mountaineering skills to hunt this sure-footed climber. Those that occasionally kill goats are bears, wolves, mountain lions, and even wolverines and eagles. Where predation has been quantified, grizzlies and wolves are the most significant predators of goats. In an Alberta study, kids and yearlings were most vulnerable. On thin ledges, bears and wolves are not much of a threat. But where goats stray from steep terrain, and especially where heaps of wet snow force them to descend to coastal Alaska and British Columbia’s old growth forests, bears and wolves more readily dine on mountain goat fare. Elk typically prefer forests and meadows, like the group of cows and calves here, rather than the rugged country used by mountain goats. (Photo by Diana Stratton) Every spring hundreds of thousands of elk (Cervus elaphus) migrate to summer ranges in the mountains of the West. (Photo by the author) Black bears (Ursus americanus) cruise the more gentle terrain on goat ranges and scavenge on winter-killed animals, often where carcasses have been deposited by avalanches. (Photo by author) A common carnivore in rugged terrain, and the predator probably best adapted for preying on the mountain goat, is the mountain lion or cougar (Puma concolor). It can reach 200 pounds in weight. (Glacier National Park archives) The golden eagle (Aquila chrysaetos) is a powerfully built bird of prey capable of batting a young goat from a cliff. (© Ganesh K. Jayaraman) Coyotes (Canis latrans) are both predators and scavengers. Their prey largely consists of much smaller species than the winter-killed elk that this one is scavenging. (Photo by author) 61 R E W A R D S A N D R I S K S The mountain lion is large and powerful enough to bring down the white mountaineer . And it’s the predator most often found prowling goat-rugged terrain. As lion numbers have increased in recent decades, predation on goats may also have risen. The fifteen-pound golden eagle, on the other hand—though a fierce hunter of smaller mammals and birds—seems unsuited for killing prey the size of goats. Indeed, it picks its targets carefully, seeking young kids to carry away or to strike and knock from cliff ledges. After gravity has done its work, the eagle feeds on its fallen victims below the cliffs. Bald eagles have also attacked young goats. To counter the eagle, nannies tuck their young beneath them when the large bird soars overhead. Even the shadow of a raven or red-tailed hawk may cause a mother to shield a newborn with those stiletto horns held at the ready. This protective behavior of nannies probably limits the vulnerability of kids, unless they are left unguarded. The consensus from ecological studies suggests that eagle predation is of limited consequence to the wellbeing of goat herds. The most common predator on many goat ranges south of Canada is the coyote, and this was true of the Bitterroots as well. Most often I spotted them coursing terrain below the cliffs, mousing or seeking the remains of winter-killed goats to scavenge. During February 1974, I peered anxiously through my spotting scope as one harassed a nanny and kid. The coyote repeatedly attempted to dissociate the pair by seemingly daring the nanny to charge. When the nanny dropped her headgear into assault position and obliged, the coyote dashed aside and cut behind her. Nevertheless, she recovered each time to chase the coyote from her kid and eventually routed him. In another instance, a pair of coyotes confronted a nanny and kid on the narrowest stretch of ledge. The nanny stood over her youngster and simply waited the...