Since sunlight cannot penetrate to the bottom of these deep lakes, they are deprived of bottom-anchored plants in midlake as well. As a result, herbivorous animal life must depend almost wholly on algal growth. Wave action inhibits the spread of free-floating algae by washing much of it onto the shore. Deep lakes are also low in available oxygen, preventing the development of bottom decomposers, which would rapidly release nutrients as they break down the accumulating debris washed into the lake. Without a steady supply of nutrients, plant growth is retarded. Since the food chain depends upon green plants, the ability of a lake to support higher animals such as fish depends upon its ability first to produce adequate plant growth. The production of one kilo of trout requires that a lake produce about 1,000 kilos of plants to support 100 kilos of herbivorous invertebrates, which are eaten by 10 kilos of carnivorous insects, on which the trout feed. Compared to smaller shallow lakes, which teem with visible life, cold, deep, nutrient-poor lakes such as McDonald appear to be watery deserts. Yet because of their great volume—Lake McDonald contains 5 or 6 cubic kilometers of water—these large lakes do sustain significant numbers of fish. Of the 22 kinds of fishes found within the park, most are coldwater species. Trout, whitefish, grayling, suckers, minnows, and carp fill the roles of herbivore, carnivore, and scavenger. Agile, highly mobile, and acutely sensitive, fish represent the most successful total adaptation to the aquatic environment. Through the stocking of nonnative species, including plantings in formerly fish-free lakes, the natural aquatic communities of many of Glacier’s lakes and streams have been permanently modified. Aquatic food chains are not confined to the water. Ospreys, ducks, mergansers, otter, mink, and many other semi-aquatic or terrestrial birds and mammals utilize the plants and animals of the water. In fall, a remarkable spectacle occurs along the outlet of Lake McDonald. Attracted to the kokanee salmon concentrations, which run from Flathead Lake to spawn and die in these clear, shallow waters, bald eagles collect to exploit the vulnerable fish. In 1977, 444 eagles were counted in one census. This food resource is also exploited by grizzlies, coyotes, skunks, gulls, loons, and other animals. On occasion, even white-tail deer have been observed swallowing salmon! [Illustration: Sunset] Shooting Stars This park is very special. The people who know it well feel proprietary toward its mountains, scattered lakes, and glaciers. Perhaps it is the arrangement of the land, an unsurpassed concentration of American wilderness. Time and again I have thought, as I regarded some aspect of this country, _yes, this is exactly right_—almost, it would seem, as if some magic existed that could translate thought and emotion into rock and bark.