Game, the U.S. Forest Service, and Audubon California. The South Fork Kern River riparian forests support breeding populations of a number of special status bird species that breed nowhere else in the Sierra, such as Yellow-billed Cuckoos, “Southwestern” Willow Flycatchers, Brown-crested Flycatchers, Vermilion Flycatchers, and Summer Tanagers.
FIGURE 8 Riparian forest (photograph by Phil Robertson)
Overall, remaining lowland riparian forests along West Side rivers and streams support a higher density and diversity of breeding and migratory birds than any other Sierra habitat. Numbers of migratory birds in riparian areas can be more than 10 times greater than found in the surrounding uplands. Draped in wild grapes, berry vines, or poison oak, these lush groves offer moisture and shade during the hot summers. Breeding birds like Yellow Warblers, Yellow-breasted Chats, Warbling Vireos, House Wrens, and Black-headed Grosbeaks sing above the constant din of humming insects, while Downy and Nuttall’s Woodpeckers drill on branches and flake off bark. Other typical Sierra riparian birds include Black Phoebes, Pacific-slope Flycatchers, Ash-throated Flycatchers, House Wrens, Orange-crowned Warblers, Spotted Towhees, Song Sparrows, and House Finches.
In the Lower and Upper Conifer zones, riparian forests mostly become narrow, discontinuous corridors of dogwood, black cottonwoods, and aspens or, more typically, tall willows or alders. In the Subalpine zone, shrubby willows and alders form a narrow and patchy border along most streams. Narrow stands of moisture- loving deciduous trees also border some ponds and lakes throughout the high Sierra. In all these ecological zones, deciduous trees often replace conifers along streams, especially in steep terrain. Song Sparrows and Yellow and Wilson’s Warblers breed in these broad-leaved trees, and migrant vireos, warblers, sparrows, finches, and tanagers flock to them in late summer and fall. Turbulent mountain streams are home to Common Mergansers, American Dippers, and rarely Harlequin Ducks. Nearby sandbars may harbor nesting Spotted Sandpipers or perhaps a family of Killdeer.
Aspens commonly form large broad-leaved woodlands in the high mountain regions and dominate riparian areas along the entire East Side, where they are joined by cottonwoods and willows. The pale, light green leaves or yellow autumn hues and white bark provide a dramatic contrast to the various coniferous forest communities that span their range in the Sierra. Aspen woodlands provide important breeding, resting, and foraging habitat for a diverse array of birds that eat the buds, flowers, seeds, and catkins of quaking aspens and supply a yearlong food source for Sooty Grouse. Typical nesting birds include Red-breasted Sapsuckers, Hairy Woodpeckers, Northern Flickers, Warbling Vireos, Tree and Violet-green Swallows, MacGillivray’s and Yellow Warblers, and Song Sparrows. Breeding raptors may include Great Horned Owls, Cooper’s Hawks, and Northern Goshawks.
FIGURE 9 Mountain meadows
Mountain Meadows
Mountain meadows usually begin as lakes that are gradually filled with sediment from the surrounding uplands and may someday become forests. Grasses, sedges, and rushes share the moist central portions with wild onions, corn lilies, shooting stars, and countless other wildflowers, while young trees gradually colonize the edges. These meadows are most numerous and extensive in the glaciated terrain of the Subalpine zone but are also scattered throughout the Lower and Upper Conifer zones of the Sierra. They range in size from small forest clearings to wide expanses such as Tuolumne Meadows in Yosemite National Park, the largest example of these high-country flower gardens in the Sierra. Perazzo Meadow in Sierra County is another spectacular, and recently protected, mountain meadow paradise. One can walk for miles in any direction through these vast expanses, encountering Calliope Hummingbirds, Golden Eagles, Prairie Falcons, American Kestrels, Willow Flycatchers, Dark-eyed Juncos, Chipping Sparrows, and Mountain Bluebirds along the way. Unfortunately, many of the Sierra’s largest and most spectacular meadows, such as Hetch Hetchy Valley in Yosemite National Park, are now buried beneath the waters of human-made reservoirs.
Growths of shrubby willows tracing the main stream courses in wet mountain meadows harbor birds such as Willow Flycatchers, Lincoln’s Sparrows, and MacGillivray’s Warblers. Abundant mosquitoes, dragonflies, and butterflies dance in the air while Western Wood- Pewees and Olive-sided Flycatchers perched at meadow’s edge scan for these and other insects. Wet meadows stay green all summer, while dry grassy sites atop domes and ridges usually turn brown and go to seed by the end of August. The margins of many Sierra meadows are ringed by aspens or cottonwoods that display a brilliant gold when framed against a blue October sky. Whether rimmed with broad-leaved trees or ranks of conifers, forest-meadow edges attract birds like Western Bluebirds, Yellow-rumped Warblers, Chipping Sparrows, Dark-eyed Juncos, and Purple Finches that forage among meadow plants for insects and seeds and take to the trees for cover.
The edges of forests and mountain meadows are among the most rewarding for birdwatchers. During the night, cold air flows down into meadow depressions and by dawn these areas become significantly colder than nearby forests. Like humans, birds seek warmth at dawn and usually flock to the sunny sides of mountain meadows. Sandhill Cranes and Wilson’s Phalaropes sometimes nest in wet meadows on the East Side. Dense forests near meadow edges provide nesting habitat for raptors such as Northern Goshawks and Spotted Owls. Great Gray Owls primarily search for prey in these mountain meadows.
FIGURE 10 Freshwater marshes
Freshwater Marshes
Freshwater marshes are distinguished from deep water aquatic habitats and wet meadows or grassland habitats by the presence of rushes, sedges, or tall, erect, grasslike plants such as tules and cattails that are rooted in soils that are permanently or seasonally flooded or inundated. Marshes can occur in basins or depressions at all elevations, aspects, and exposures, but they are most common on level to gently rolling topography below about 4,000 feet but can be found above 8,000 feet in the southern Sierra. On the West Side, freshwater marshes are mostly confined to the shallow edges of reservoirs and ponds; the largest ones are at Lake Almanor in the north and Lake Isabella in the south. On the East Side, sizable marshes can be found at Honey Lake, Sierra Valley, and Carson Valley, at such large lakes as Bridgeport Reservoir, Lake Tahoe, and surrounding Mono Lake. Freshwater marshes also occur as fringes around reservoirs such as Lake Crowley where the slopes are gentle enough to create a rim of shallow water. On slow-moving meadow streams, freshwater marshes can occur as narrow bands over long distances.
Freshwater marshes teem with bird life. Where shorelines are clogged by tules, cattails, or rushes, these aquatic habitats harbor Canada Geese, Mallards, Cinnamon Teal, Virginia Rails, Soras, American Coots, Common Gallinules, Wilson’s Snipe, Marsh Wrens, Common Yellowthroats, and throngs of Red-winged Blackbirds, while Great Blue Herons stand like statues in the shallows.
Reservoirs, Lakes, and Ponds
Most Sierra “lakes” are actually artificial reservoirs. More than 150 reservoirs exist on West Side rivers and creeks, and the largest of these (more than 5,000 surface acres) are Lake Almanor and Lake Oroville (Feather River), New Melones Lake (Stanislaus River), Don Pedro Reservoir (Tuolumne River), Lake McClure (Merced River), Millerton Lake (San Joaquin River), Pine Flat Lake (Kings River), Lake Success (Tule River), and Lake Isabella (Kern River). On the East Side, examples of large reservoirs include Lake Davis (Plumas County), Stampede (Sierra County), Prosser Creek and Boca (Nevada County), Topaz Lake (Douglas County, Nevada), Bridgeport Reservoir, and Crowley Lake (Mono County).
FIGURE 11 Reservoirs, lakes, and ponds (Mono Lake)
Fish-eating birds such as Ospreys and Bald Eagles patrol
