Birds of the Sierra Nevada. Ted Beedy

      ORIGIN OF NAMES “White-faced” for the white facial feathers of breeding birds; “ibis” is an Egyptian name taken from Sacred Ibis (Plegadis aethiopicus) that was mummified and depicted on tombs; Gr. plegas, sickle, for curved the bill; chihi is probably a native South American name for this bird.

      NATURAL HISTORY White-faced Ibis are strong fliers that depend on ever-changing seasonal wetlands, requiring them to constantly move in search of productive feeding areas and secure nesting sites. They forage by probing their long, decurved bills into shallow water or moist soil searching for aquatic and moist-soil insects, crustaceans, and earthworms. They prefer shallow marshes with islands of cattails or tules but also forage in upland soils, including agricultural fields—especially rice.

      While males are slightly larger, both sexes have identical plumage and display beautiful metallic green and bronze hues in the breeding season. A thin white border of feathers surrounds their bills, hence their common name “white-faced.” These white markings, as well as their iridescent plumage highlights, are lost when they molt into winter plumage.

      These long-legged waders emit soft grunts and oink calls at their nesting colonies or when flushed. They fly in long, undulating lines, constantly shifting positions with strong, rapid wingbeats and alternating glides. They normally fly fairly close to the ground, but flocks also climb to great heights before making dramatic dives—pulling up just before hitting the ground.

      In California, ibis initiate nesting in shallow, freshwater marshes from mid-April until late May. Both sexes participate in nest building, bending stems of partially submerged cattails or bulrushes over to form a woven platform just above the water’s surface. Nests may be hard to see, hidden deep within dense patches of emergent vegetation, but their colonies are obvious with ceaseless traffic of dark birds entering and leaving the marsh. Nesting colonies move to new sites when water levels or other conditions change. Females lay three to four greenish or bluish eggs, marked with dark spots or scrawls that both sexes incubate for about 22 days. By about three weeks after hatching, fledglings can move a short distance to acquire food from their parents, and by five weeks the adults start leading the young on a series of short flights through the colony, feeding them at each stop.

      STATUS AND DISTRIBUTION White-faced Ibis are now common residents of the Central Valley (see “Trends and Conservation Status,” below), and they occasionally stray into the Sierra.

      West Side. Rare postbreeding wanderers can be seen at low-elevation marshes; regular but uncommon in the Kern River Valley in spring and fall.

      East Side. Nesting has been observed at a few isolated marshes north of Truckee and intermittently at Honey Lake since the mid-1970s, with the largest colony at Sierra Valley (hundreds of pairs in wet years but absent during dry years); they wander widely during migration and after the nesting season and might be seen in large wetlands or agricultural areas; accidental in winter.

      TRENDS AND CONSERVATION STATUS Formerly common nesters the length of California, Whitefaced Ibis were reduced to very low numbers by the 1960s and were included on the list of California Bird Species of Special Concern in 1972. The principal cause of their dramatic decline was draining of Central Valley and coastal marshes; eggshell thinning due to DDT was also implicated. In the late 1970s ibis began returning to the state in numbers, possibly in response to inundation of historical marsh nesting areas at the Great Salt Lake. Their breeding population has increased steadily since. The species was rarely recorded on Central Valley Christmas Bird Counts in the 1970s and 1980s before numbers began to grow exponentially from the early 1990s and reach a plateau in recent years. For example, the species was nearly unseen in the 1980s at Lake Almanor, where it is now common in mid- to late summer. Flocks numbering in the tens of thousands now roam marshlands and agricultural fields of the Central Valley and northeastern California to the extent that in 2008 they were removed from California’s list of Bird Species of Special Concern. Increases in Central Valley managed wetlands and winter flooding of rice fields may have contributed to the recovery of the species in California.

       NEW WORLD VULTURES

      Family Cathartidae

      New World vultures are large scavengers with long, broad wings enabling them to soar great distances in search of carcasses. These carrion-eaters have extraordinary vision and can find dying or recently dead animals from high in the air. They often feed by thrusting their featherless heads into the body cavities of rotting animals, so baldness avoids the problem of chronically soiled head feathers. Of the seven species in this family, Turkey Vultures are fairly common to abundant in the Sierra, and California Condors historically nested there. The family name is derived from Gr. kathartes, a cleanser or purifier, for their habit of cleaning up carcasses.

      Turkey Vulture

      Cathartes aura