Sage Grouse Saga

Greater sage grouse, the largest grouse in North America, inhabit sage grasslands of the Intermountain West, from Colorado to the Columbia Plateau and from southern Alberta to southern Utah. Closely tied to their habitat, these grouse feed solely on the sage plant in the winter while supplementing that diet with a variety of forbs, insects and grasses during the warmer months. Unlike many game birds, they do not possess a muscular crop and cannot digest hard seeds.

Come spring, sage grouse gather in clearings (known as leks) at dawn and dusk, where the dominant males attract mates with ritualized strutting, tail fanning and a variety of noises from their air sacs; most of the females mate with only one or two of the performers. Nests are placed on the ground and females are solely responsible for both incubation and protection of the young; six to twelve eggs are generally produced. Able to forage soon after birth, the young are vulnerable to a wide range of predators, including snakes, prairie falcons, crows, magpies, badgers, coyotes, bobcats and owls.

Once abundant across the American West, greater sage grouse have long been threatened by habitat loss; their population, estimated to have been about 16 million in the early 1900s, has fallen to less than 500,000 today, a drop of 97% over the past century. The loss of sage grasslands to mining, ranching and oil production has been primarily responsible for this decline and efforts to list the greater sage grouse as an Endangered Species have been successfully blocked by Western Governors and their Federal colleagues. Perhaps a 99% population decline will be more convincing.

The Western Ibis

Cousin to the glossy ibis of the Southeastern U.S., the white-faced ibis winters along the Gulf Coast (from Louisiana to Texas), in valley wetlands of central and southern California and in Mexico. While some are permanent residents in these areas, most migrate through the central and western U.S. to breed on freshwater wetlands of the Northern Plains and Intermountain West.

Since wetland conditions tend to vary across the dry country of the Western U.S., these nomadic migrants are opportunistic, choosing their colonial nest sites based on the conditions that they find; for this reason, their numbers in any given area varies widely from year to year. Preferring broad, shallow wetlands with islands of vegetation, white-faced ibis nest in marsh grasses or in low trees along the shore. Both parents incubate the 3-4 eggs and participate in feeding regurgitated insects, worms, amphibians and small fish to the nestlings; the young are fledged within a month and are self sufficient by August.

Known to wander widely in late summer, small flocks of white-faced ibis turn up in the eastern U.S. on occasion but generally return to their traditional wintering grounds by mid autumn. Peak spring migrations across the Great Plains generally occur from mid April to early May and it is then that most of us encounter these attractive birds, stopping to rest and feed on shallow lakes, braided rivers or flooded fields.

Mono Lake

Mono Lake is a 70 square-mile saline lake at the eastern foot of the Sierra Nevada Range, approximately 13 miles east of Yosemite National Park. Enclosed within a natural basin by the Sierra Batholith to its west and Pliocene-Pleistocene volcanic ranges to its north, east and south, the lake is fed by three primary streams (Lee Vining, Rush and Mill Creeks) and by freshwater springs along its floor. Having formed during the Pleistocene, about 1 million years ago, it is one of the oldest lakes in North America and is the largest lake completely within California.

As a basin lake, its size and depth are a balance between inflow from streams and springs and evaporative loss in the dry climate of the Basin and Range Province. Prior to 1941, its surface elevation hovered above 6400 feet but this was dramatically lowered by diversion of inflow to the Los Angeles Water System; legal challenges by conservation groups eventually restored most of the inflow by 1994.

Despite its high salinity (2.5 times that of ocean water) and alkalinity (which precludes fish survival), Mono Lake supports a spectacular ecosystem. Photosynthetic algae, feeding on minerals from the surrounding mountains, bloom in spring when snowmelt peaks. Feeding on the algae, brine shrimp and brine flies thrive in the lake shallows and provide vital nourishment for migrating shorebirds, eared grebes and phalaropes, among other species; indeed, Mono Lake was added to the Western Hemisphere Shorebird Reserve Network in 1991. California gulls and snowy plovers nest on Paoha Island and smaller islets, escaping predation by fox and coyotes. Beyond the abundant birdlife, Mono Lake is perhaps best known for its tufa towers of calcium carbonate, produced by the interaction of freshwater springs and the alkaline, mineral-rich lake waters. Students of geology will also appreciate the surrounding volcanic landscape, including the relatively recent Panum and Mono-Inyo craters, south of Mono Lake.

Mt. Shasta

Towering above the landscape of Northern California, at the southern end of the Cascade Range, Mt. Shasta is a composite of four volcanic cones, the first of which began to form just 600,000 years ago; with a summit elevation of 14,168 feet, it is second only to Mt. Ranier among the Cascade volcanoes.

The current summit crater of Mt. Shasta, 600 feet across, tops the Hotlum Cone, which formed about 8000 years ago and has been erupting every 600-800 years; the last significant eruption was 200 years ago. Mt. Shastina, topping out at 12,330 feet, is an older cone that now appears as a prominant satellite peak to the west of Shasta's primary summit; the Whitney Glacier, one of five glaciers that grace Mt. Shasta, lies between the two peaks. Tributaries arising from Shasta's ice sheets feed the Klamath River to the north (primarily via the Shasta River) and the Sacramento River, to the south.

Since Mt. Shasta rises almost 10,000 feet above its immediate surroundings, this magnificent massif can be seen from up to 150 miles away. Though classified as a dormant volcano, Shasta is not extinct, as indicated by active fumeroles along its flanks. Another explosive eruption is expected within a few hundred years....if not next month!

The Owens Valley

The Owens River of southeast California rises along the eastern flank of the Sierra Nevada Mountains, at the southeast edge of Yosemite National Park. After flowing eastward through the Long Valley Caldera, the river angles to the south-southeast and begins its journey through the magnificent landscape of the Owens Valley.

The Owens Valley is a geologic graben, a block of crust that dropped between the parallel faults of the Sierra batholith to its west and the White-Inyo fault block mountains to its east; as the mountains rose on either side, this block slipped downward. The floor of the valley has an elevation of 4000 to 3500 feet (north to south) while its steep walls rise toward some of the highest summits in the Lower 48; the latter include Mt. Whitney in the Sierra Nevada (14,498 feet) and White Mountain Peak (14,252 feet) in the White Mountains. The latter range also includes Boundary Peak (13,167 feet), the highest point in Nevada, while the Inyo Mountains, known for their exposure of Cambrian sediments, top out below 12,000 feet.

Representing the southwest edge of the Basin and Range Province, the Owens Valley lies in the rain shadow of the Sierra Nevada and receives very little moisture from the east due to the high wall of the White and Inyo Mountains. The waters of the Owens River have thus long been diverted for crop production across the Valley and, since 1913, much of its flow has been directed into the Los Angeles Aqueduct, leaving Owens Lake, the natural terminus of the river, mostly dry. Back in the Pleistocene, when mountain glaciers fed the Owens River, its lake basin spilled to the east (around the southern end of the Inyo Range), merging with lakes from other Great Basin rivers to produce an inland sea across Death Valley and adjacent lowlands.