BIGHORN SHEEP POPULATION DECLINE
This country provides an extensive summer sheep range in the high rolling tundra and rugged peaks above timberline, in addition to a large wintering area in the lower timber and valleys. Strong winds in the winter sweep snow from the scant tundra vegetation and often make it possible for sheep to feed at these high altitudes even during the winter months. Even with these adequate topographic conditions, wild sheep in the National Park since 1922 have shown a slow, steady decrease in numbers until 1941, when there were about 300 sheep present. Since this date there has been a leveling off of sheep numbers, no decided increases or decreases being evident. All the related factors probably contributing to the decline of bighorn population or their present stability at low level are not known. One substantial reason advanced has been the deficiency of mineral in sheep diet in the higher mountains, as indicated on previous pages, with a resultant weakening of sheep stock and a consequent susceptibility to parasitism and diseases found prevalent among sickened and dead sheep over a period of years. Another possibility for the decline may be present in the great increase of elk and subsequent competition for similar grass foods. The Park Service has placed salt and mineral blocks at known bighorn concentration places in an attempt to improve the physical condition of the sheep and thereby increase the sturdiness of their offspring. The results of this experiment are difficult to measure, but it is believed to have met with varying success.