The Amerioon Green-winged Teal: an Overlooked Avicultural Ornament

Abstract

Even if one follows the novel arrangement of University of Kansas Ornithologist Bradley Livezey (1991) and removes from the genus Anas the three wigeons, the Gadwall, and the Falcated and Cape Teal, placing them all in the genus Mareca, Anas, with its nearly 40 species of Mallards, shovelers, Pintails, and teal, remains an enormous genus, by far the largest in the waterfowl order.

Anas is a genus of enormously wide distribution, richly represented on every continent, with members scattered on remote islands, and wellada pted subspecies fringing both Poles. Several species themselves have great ranges, in particular those that breed throughout North America, Europe, and Northern Asia, the vast area collectively designated the Holarctic Realm by zoogeographers.

The Holarctic members of the genus Anas are among the most familiar birds to the American public, being highly prized by hunters, and welcome visitors to city parks and other public waters especially during migration. Though the Mallard (Anas platyrhynchos), the ancestor of all Eurasian domestic ducks, has distinct subspecies in Greenland, Hawaii, Laysan Island, Mexico and the American southwest, the U.S. Gulf Coast and the Florida Peninsula, throughout the rest of its vast transhemispheric range it exhibits no significant variation. Likewise, aside from its two dull-plumaged subspecies in the Sub-Antarctic Kerguelen and Crozet islands, the Northern Pintail (A. acuta) is recognized by taxonomists as the same bird in California's Central Valley, the Nile delta, the French Camargue, and Lake Baikal. Indeed, Pintails have crossed both the Atlantic and Pacific in their annual migration, regularly migrating "also far to the East and to the West" (Kolbe, 1979). The Northern Shoveler (A. clypeata) has no subspecies at all.

In contrast, the Green-winged Teal of Continental North America, (Anas crecca carolinensis), is immediately distinguished from its Eurasian counterpart (A. c. crecca), by the male's possession of a striking white bar, in front of, and at a right angle to, the bend of the wing. This is totally lacking in Old World birds, who instead are distinguished by a horizontal white stripe running the length of the folded wing, and a very fine but distinct white line between the beautiful green and chestnut fields on the head. A. c. crecca is also slightly smaller, averaging about 7% less in mass than A. crecca carolinensis (Todd, 1979). Somewhat intermediate in size, though sometimes heavier than mainland-American birds (Todd, 1979), are the non-migratory Greenwinged Teal of the Aleutian Islands, (Anas crecca nimia), otherwise almost identical to the Eurasian subspecies, from which they are obviously derived. Every year, American birdwatchers spot several Eurasian Green-winged Teal along America's North Atlantic coast, and they have been reported occasionally from the Pacific coast and the interior as well (Terres, 1980). I am not aware of any of these "accidentals" breeding in North America. The drably speckled females of all three subspecies are almost identical (Todd, 1979).

At an average mass of 350 g (Todd, 1979), the American Green-winged Teal is the smallest of all U.S. ducks, with the above-noted possible exception of the Aleutian subspecies. Collectively, Anas crecca is the smallest Anatid north of the Equator.

In the breeding season, American Green-winged Teal nest practically everywhere in western and central North America, from north-central Alaska to southern California and New Mexico (Todd, 1979; Terres, 1980). Traditionally, the Atlantic Coast breeding range was largely confined to Canada, with only occasional nestings in New England (Terres, 1980). Since the 1970s, the Atlantic breeding range has been extending south, the first Maryland nest being discovered in 1971 (Terres, 1980).

Migration in North America is somewhat variable. During mild winters, birds may not go south at all, even in Nova Scotia and Newfoundland (Terres, 1980). Alaskan birds appear to winter as far north as British Columbia, while other populations winter throughout the continental U.S. and Mexico. Although they may occasionally reach Colombia (Davis, 1972), the vast majority of American green-wings remain on the continent, very few wintering in the Caribbean or south of Mexico (Todd, 1979; Terres, 1980).

Migrating in large flocks, they have traditionally been popular with hunters and large numbers are shot each season (Todd, 1979). The population appears to be stable, with recent breeding range expansion, as noted above, and may exceed three million (Todd, 1979).

Such a beautiful and abundant bird naturally attracts the attention of aviculturists, yet, in practice, the American Green-winged Teal is not a comparatively commonplace duck in public or private collections, and, where present, is usually not the center of attention.