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ORIGIN OF NAMES Gadwall is a name of unknown origin; L. anas (see family account above); L. strepera, noisy, for the loud calls—similar to a female Mallard’s.
NATURAL HISTORY Compared to other puddle ducks, Gadwalls wear subtle plumage and lack the bright, iridescent hues that characterize this group. In most places these shy ducks are outnumbered by other species, but they have one of the widest distributions of any of the world’s waterfowl and occur on all continents except South America, Australia, and Antarctica.
Gadwalls are primarily freshwater birds but also visit saline and alkaline waters—even in the breeding season. They nest on dry ground near ponds and marshes surrounded by lush aquatic vegetation such as cattails and bulrushes; islands are preferred nest sites. Monogamous during the breeding season, most females are paired by November, many months before they nest in mid-April. Nests consist of shallow depressions lined with aquatic vegetation, feathers, and down. After breeding, Gadwalls roost and forage on large marshes, lakes, and reservoirs in mixed flocks with other puddle ducks and American Coots. They usually forage in deeper water than other puddle ducks, where they upend or make shallow dives for aquatic plants, seeds, and aquatic invertebrates.
STATUS AND DISTRIBUTION Gadwalls are year-round residents and migrants in California, including both sides of the Sierra.
West Side. Uncommon breeders below about 3,000 feet in the central Sierra; confirmed nesting locations include Lake Almanor, Don Pedro Lake (Tuolumne County), Millerton Lake (Madera and Fresno Counties), Lake Success, and Lake Isabella; rare in fall up to about 8,000 feet in Yosemite National Park.
East Side. Common nesters at marshes and creek deltas; in fall, large numbers congregate on large lakes and reservoirs; fairly common in winter.
Eurasian Wigeon
Anas Penelope
ORIGIN OF NAMES “Eurasian” refers to the typical distribution of the species; “wigeon” from F. vigeon, a whistling duck; Gr. penelope, a weaver; possibly a mistaken form of penelops, duck.
NATURAL HISTORY The bright reddish heads, cream-colored crowns, and silvery flanks of male Eurasian Wigeon stand out in large flocks of wintering waterfowl. Females, however, look nearly identical to female American Wigeon. While Eurasian Wigeon do not breed in North America, some Russian Far East breeders follow flocks of the far more abundant American’s on their southward journeys. Larger wintering flocks of American Wigeon (i.e., 50 to 100 birds) may contain at least one Eurasian Wigeon. The wintering behavior and ecology of Eurasian and American Wigeon are nearly identical.
STATUS AND DISTRIBUTION Eurasian Wigeon are one of the most abundant and widespread ducks in Asia and Europe and uncommon winter visitors to California.
West Side. Uncommon to rare November through March, mostly on ponds and lakes in the Foothill zone; recent winter and early spring records from large reservoirs such as Lake Almanor and Lake Isabella; has been nearly annual recently on the Springville Christmas Bird Count (Tulare County).
East Side. Uncommon to rare at large marshes and reservoirs in late fall, winter, and early spring.
American Wigeon
Anas Americana
ORIGIN OF NAMES “American” to distinguish the species from Eurasian Wigeon; L. americana, of America
NATURAL HISTORY Most American Wigeon breed in the prairies and tundra of Canada and Alaska, but they also nest in small numbers in the Great Basin, north and east of the Sierra. Migrants arrive by mid-November to spend the winter in California. Mostly vegetarian, they feed at the surface for such aquatic plants as pondweeds, wild celery, and algae. At times, they associate with divers, such as Lesser Scaup, Canvasbacks, and Redheads, and steal aquatic vegetation after these ducks surface from dives. Wigeon are drawn to wet pastures, urban parks, and golf courses, where they graze on grasses, usually not in association with domestic ducks or geese. In winter, they consume primarily aquatic and terrestrial insects and small mollusks. On hunting days in the Central Valley, American Wigeon and other dabbling ducks sometimes flock to protected ponds and wetlands of the western foothills to escape hunting pressure.
STATUS AND DISTRIBUTION Abundant winter visitors to the Central Valley and coastal California, American Wigeon occur regularly on both sides of the Sierra.
West Side. Fairly common to locally abundant fall, spring, and winter visitors to larger reservoirs such as Lake Isabella, Lake Almanor, and Millerton Lake, and fairly common visitors to ponds and lakes in the Foothill zone; in fall, rare or casual at higher elevations.
East Side. Fairly common in winter and common in spring and fall migration at marshlands, ponds, and slow-moving creeks, with especially large numbers concentrating at Sierra Valley, Honey Lake, Bridgeport Reservoir; breeds on rare occasions in Mono County (most recently at Crowley Lake in 2007).
Mallard
Anas platyrhynchos
ORIGIN OF NAMES Mallard was apparently derived from L. masculus, male, referring to the drakes; platyrhynchos, flat-billed, from Gr. platus, flat, and rhynchos, a bill.
NATURAL HISTORY Mallards are the most abundant, widely distributed, and best known ducks in the Northern Hemisphere. Bred in captivity since ancient times, they are the ancestors of most domestic breeds, including white “Peking” ducks as well as other barnyard ducks, save for a few breeds that are derived from unrelated Muscovy Ducks that occur in the wild from South Texas to South America.
Highly promiscuous, male Mallards try to mate with as many females as possible—often very aggressively with several males chasing and trying to copulate with a single female on land or while pushing her under water until she nearly drowns, called “rape attacks” by some. Although wild Mallards rarely mate with other species, captive birds have produced fertile offspring with more than 40 different species of ducks and geese. Domestic flocks of ducks in urban parks and barnyards often feature the odd-looking progeny of such mixed-matings.
In flight, Mallards have large, broad bodies and slower wingbeats than most other ducks. They walk proficiently on land and fly directly up from the water when flushed. They mostly feed in shallow water by tipping-up but also make shallow dives for food, unlike most puddle ducks. They primarily consume submerged aquatic plants such as pondweeds, smartweed, and bulrush. In summer they also take animal foods, including the larvae and nymphs of mayflies, stoneflies, and midges.
These hardy and adaptable ducks will nest almost anywhere adequate food supplies exist. Similar to Canada Geese, they adapt rapidly to artificial habitats and are frequent visitors to ponds at farms, golf courses, and urban parks. They hide their ground nests under tall grasses or dense marsh vegetation. Females care for their young for about two months until they are capable of flight.
STATUS AND DISTRIBUTION Mallards are the most abundant ducks in the Sierra, and their distribution has expanded during the past decades with the creation of ponds, reservoirs, and other artificial wetlands, allowing them to colonize almost anywhere.
West Side. Common nesters up to about 4,000 feet in the central Sierra; uncommon at higher elevations, a few pairs
