In his essays, John Muir blended astute scientific observation with an adoring paean to "the immortal beauty and immortal truth of Nature." He wrote lovingly of the animals and plants he studied he studied as he trekked through the California wilderness, especially the Yosemite Valley.
His poetic raptures notwithstanding, Muir was one of the first naturalists to recognize the importance of predators in maintaining the balance of nature, even on cultivated land. In an account of a massive jack rabbit hunt in the San Joaquin Valley, he decries the anthropocentrism that leads humans to seek an immediate use for a species or exterminate it. The hunt was a product of the ranchers thoughtlessly policy of killing coyotes, hawks and snakes. Freed from their natural predators, the jack rabbit population expanded until the animals threatened to nibble all the plant life out of existence.
An essay on the slaughter of the passenger pigeon strikes a poignant note: Muir and the last member of that species, whose enormous flocks once darkened the Midwestern sky, both died in 1914.