The greatest natural threats to mountain goats are starvation in late winter, avalanches, falls from steep cliffs and predation. The greatest threats from humans are poorly regulated hunting and displacement from natural habitat by industrial resource extraction and motorized recreation. Poor hunting practices prior to the 1970s resulted in the extirpation (local extinction) of mountain goats in many areas of the United States, British Columbia and Alberta. (see Hunting)
Predators
Natural predators include grizzly, black bear, wolves, wolverine and cougar. Golden eagles can knock small new-born kids off rocky ledges.
Winter survival
Mountain goats depend on body fat reserves accumulated in summer and fall to survive the brutal cold and wind of winter. Feed is available under the snow but the food value is low. Feeding in winter may just maintain health. Goats spend a lot of time sleeping in winter to lower the demand for calories. They also restrict their movements and may occupy an area as small as 8 hectares for the winter.
If they are disturbed by predators or humans, the exertion needed to flee may rob them of vital fat reserves. Fleeing also may expose the goats to avalanche hazards or may force them into a new location with less valuable feed. In winter, goats prefer sunny south-facing slopes where snow cover is thin and plants start new growth early. Starvation may occur in late winter and early spring when fat reserves are depleted and new plant growth is delayed by deep snow.
Ring of snow
At certain times in winter, there is a ring of deep, soft powder snow around each mountain in our area at timberline that separates the forested valley from the high windswept ridges in the alpine. The snow is so soft that large predators have great difficulty moving from the lower valley to the sub-alpine and alpine home range of mountain goats. As long as the snow remains soft and deep and the predators are unable to travel through the ring of snow, the goats are protected from large predators. Of course, snow conditions change. Sun, rain and wind can change the soft powder snow into a rock-hard surface that will support the weight of any predator. Humans can also create trails through soft powder snow by skiing, snowshoe use, snowmobile or snowcat. The trails harden within an hour and can support the weight of many predators. Any human-made trails that go from the valley to the alpine can allow predators access to mountain goats that otherwise would be protected from predators by the ring of snow.
Snow compaction
In winter, mountain goats often paw through soft snow to feed on lichens, dry grasses and flowering plants. If the snow is compacted, the amount of energy expended to paw increases. Or pawing may become impossible. Any man-made snow compaction can affect mountain goats and may force them to move to a new feed range. Moving in winter expends vital energy from fat reserves and the new range may have feed of lower quality. Compaction in small areas can be by skis or snowshoes. Large areas can be compacted by snowcats or snowmobiles.
Climate change
Mountain goats adapt to very cold temperatures and winter wind but they suffer in the summer heat. The southern boundary of their range is defined by heat stress mountain goats would suffer in areas to the south or at lower elevations.
Climate change will impact mountain goats in two ways. Higher temperatures will cause trees to grow at higher elevations on mountainsides which will shrink the available alpine area. Climate change will also increase the ambient temperature and force mountain goats higher on a mountain to avoid summer heat. This double squeeze will reduce mountain goat habitat and may reduce the abundance and variety of feed plants.
Forest fires
Some mountain goats depend on winter range where wildfires have promoted the growth of early seral vegetation high on forested slopes. Control of wildfires has reduced available feed. It may be necessary to let wildfires or controlled burns continue up specific forest slopes that benefit the goats.
Loss of dispersal routes
Some mountain goats disperse from their home range to travel across forested valleys to reach other mountains. Dispersal is important for genetic health of the population and to permit occupation of new habitat. Mountain goats travel across rivers, farms, forestry cut blocks, highways, railways, barbed-wire fences and through populated rural and town sites during dispersal. If a mountain goat is stopped or delayed by an obstacle or human activity, the dispersal may not succeed and the benefits of dispersal are lost.
Disturbance by aircraft
Studies show that mountain goats are disturbed by aircraft flying nearby, especially helicopters. In addition, goats do not habituate to the fly-overs and react to each and every flight so that the effect is additive. Repeated alarm responses may impact body condition, the success of reproduction and eventually the population of the herd. Alarm responses may also cause temporary displacement or abandonment of an area. Recommendations for buffer zones for aircraft range from 1-1/2 to 2 kilometers horizontally and 500 meters vertically.
