ORIGIN OF NAMES “Harlequin” for this species’ multicolored plumage, reminiscent of the brightly colored characters of the pantomime stage; L. histrionicus, related to L. histro, actor.

      NATURAL HISTORY Nesting Harlequin Ducks prosper amid swirling torrents and rapids of mountain streams. According to William Dawson (1923): “A baby Harlequin is as thoroughly at home in wild waters as a baby trout. The trout we may seduce with worm or fly, but until we have devised an equally interesting method for attracting young Harlequins, our meetings are likely to be infrequent.” As Dawson implied, Harlequins were considered rare in the state by the early 1920s.

      In the late 1870s, Lyman Belding (1891) reported: “I have noticed many of these ducks on the principal streams of Calaveras and Stanislaus counties in the summer. . . . I find young broods from about 4000 feet upward, the earliest apparently hatched about the first of June, or earlier, and have often surprised the mother ducks with their broods hidden in Saxifrage . . . when I approached within a few feet of the brood . . . all would hurriedly swim from me, vigorously using both feet and wings to propel themselves against or with the rapid currents.” While no nests of these hardy ducks have been described in California, Harlequins elsewhere nest on the ground, under the shelter of driftwood or rocks, and always beside swift, flowing rivers. They sometimes nest on cliff ledges and in cavities in trees and stumps lined with conifer needles, mosses, or leaf litter. Nest building begins from early May to early June, and they only produce one brood per year. Females care for their precocial young alone, when they often move to slower stretches of nesting streams.

      Harlequins are adept underwater swimmers, and they seek clear, cold rapids, where they search rock crevices for aquatic insects including the adults, nymphs, and larvae of caddisflies, mayflies, and stoneflies. They use their huge feet to navigate the bottoms of rushing steams over wet, polished stones—much like American Dippers, which share their summer haunts and their favored prey.

      STATUS AND DISTRIBUTION Most Harlequins currently wintering along the California coast are from northern breeding populations, but a few pairs probably nest along remote rivers of the Sierra each year in greatly reduced numbers from their historical population.

      West Side. Rare, all historical records from turbulent headwaters from the Stanislaus River south to the upper San Joaquin River and specific nesting localities included Griswold Creek (tributary to the Stanislaus River), South Fork of the Tuolumne River, Cherry Creek (tributary to the Tuolumne River), South Fork Merced River, Lake Ediza (9,300 feet, near the headwaters of the San Joaquin River), and the South Fork Merced River in Yosemite Valley; also observed along the South Fork Kaweah and the South Fork Kings Rivers, but nesting there was not confirmed. Currently rare, casual, or absent from most of the historical breeding range in the Sierra; confirmed breeding records since the early 1970s include above Salt Springs Reservoir on the Mokelumne River, on the Feather River near Thermalito Forebay, and, most recently, on the Merced River in Yosemite National Park in 2002; recent breeding season observations of Harlequins (breeding status not confirmed) include North Fork Feather River, North Fork American River, Rubicon River, Silver Fork of the South Fork American River, North Fork Mokelumne River, Tenaya Creek and the South Fork Merced River in Yosemite National Park, the upper San Joaquin River, and below Friant Dam on the lower San Joaquin River.

      East Side. No historical or recent records.

      TRENDS AND CONSERVATION STATUS Harlequin Duck was added to California’s list of Species of Special Concern in 2008. Despite its rarity and declining status, this species has not been listed as either Threatened or Endangered—mostly because it is seen so infrequently and so little is known about its recent breeding status in the Sierra. The exact cause of the Harlequin’s decline is unknown. Increased disturbance from human recreational activities and damming of historical nesting streams have also reduced the suitability of many Sierra rivers for nesting Harlequins. Historical gold mining had severe but unmeasured effects on their riverine habitats and breeding populations.

      Bufflehead

      Bucephala albeola

      ORIGIN OF NAMES “Bufflehead” derives from Fr. buffle, buffalo, referring to this species’ large head; bucephala from Gr. bous, ox or bull, and kephale, head; L. albus, white.

      NATURAL HISTORY The rounded heads of these dapper little ducks reminded early ornithologists of a buffalo’s profile, hence the name Bufflehead. At a distance males look black and white, but close views reveal a bright purple and green iridescence on their heads. They sit buoyantly high on the water and can fly up directly from the surface rather than having to skitter across the water to gain speed like most diving ducks. Buffleheads fly rapidly, flashing white patches on their whirring wings. Much like their close relatives, the Goldeneyes, they dive for small fishes or search the bottom oozes for shellfish, aquatic insects, and other prey; less commonly they feed at the surface like puddle ducks.

      Most of California’s Bufflehead population breeds in forested mountain lakes of the Cascades and farther north, but recently they have been confirmed nesting in the Sierra. In April, drakes begin to actively court females and threaten other males by swimming at them with heads lowered and wings flapping. Unlike most ducks, Bufflehead pairs usually remain together for years. Their preferred breeding habitats are small ponds lined by conifers or aspens. Similar to Wood Ducks, they nest in tree cavities, usually larger ones excavated by Northern Flickers or Pileated Woodpeckers. Other cavity-nesting birds such as Western Bluebirds and European Starlings are considered competitors for suitable nest sites. Breeding activities begin in early May, and peak nesting extends from mid-May until late July. Females line their nest holes with down and feathers before laying eggs; the young remain in the nest for about a day before jumping to the ground and joining the hen on the nearest water and become independent after about 50 days.

      STATUS AND DISTRIBUTION Similar to Ring-necked Ducks and Hooded Mergansers, Buffleheads are primarily boreal ducks that have recently extended their breeding range southward into the Sierra.

      West Side. Uncommon breeders; prior to the mid-1990s, Sierra nesting confirmed only at Lake Almanor and near Buck’s Lake; recent observations have confirmed localized nesting at secluded, tree-lined lakes in Sierra, El Dorado, Placer, and Alpine Counties—most of these localities are above 6,500 feet; fairly common winter visitors and spring and fall migrants to deeper reservoirs, lakes, and ponds, mostly in the foothills below about 3,000 feet in the central Sierra.

      East Side. Recent breeding confirmed in Sierra, El Dorado, Alpine, and Inyo Counties; fairly common spring and fall migrants and winter visitors to larger lakes and reservoirs.

      Common Goldeneye

      Bucephala clangula

      ORIGIN OF NAMES “Goldeneye” for the species’ bright golden eyes; clangula, the diminutive form of L. clangor, noise, a reference to the whistling sounds of the species’ rapid wingbeats.

      NATURAL HISTORY Common Goldeneyes were once called “Whistle-wings”

---

Скачать книгу