Laysan duck

Named by Lionel Walter Rothschild in 1892, the Laysan duck is named after Laysan island, one of the Northwestern Hawaiian Islands. It is a member of the mallard clade of dabbling ducks, and is a highly unusual species, both behaviorally and genetically. Recent evidence suggests they originated from an east Asian, southern hemisphere ancestor of mallards, not from stray migratory mallards (Anas platyrhynchos) as had been reported in the past. ==Description==

The Laysan duck is teal-sized and dark brown, with a prominent white eye-ring. The bill is short and spatulate, dark green with variable black blotching in males, and dull orange with variable black blotching in females. The Laysan duck usually has a ring of fat around its neck. Some males show faint iridescence on the head or neck and have slightly upturned central tail feathers. The wing has an iridescent purplish-green patch (speculum feathers) in both sexes. Leucistism, or extensive white feathering, is common on the head and neck of older birds. The legs and feet are orange, usually brighter in the male. The annual pre-basic molt is complete, and the ducks lose all their flight feathers and become incapable of flight until new feathers grow in. Wild ducks have been known to live to the age of twelve years, and captive birds have lived to the age of eighteen. ==Behavior==

The Laysan duck is a poor flyer, but walks and runs well, with a pelvic girdle adapted to terrestrial foraging. Its wings and wing muscles are reduced; it prefers to freeze in place when pursued. Energetic foraging behavior includes a fly-snapping sprint through Neoscatella sexnotata brine fly swarms. With necks outstretched, and bills close to the ground, the ducks run along a mudflat and as clouds of flies rise up in front, snap them up by rapidly opening and closing their bills. The ducks also will dabble and filter feed along lake shallows, shore, and in upland vegetation for macroinvertebrates, algae, leaves, and seeds. During the day, and especially in the breeding season, they prefer to hide among the grass and shrub vegetation, helping them to avoid avian predators such as frigatebirds. On Laysan Island, they prefer to venture out in the open and feed on the lake from dusk til dawn, although there seems to be marked variation from year to year according to the availability of food items. Reproduction Pair formation begins in autumn, and nest building begins in spring. The female builds a well-concealed nest on the ground below dense vegetation, especially Eragrostis variabilis bunchgrass. The nest is a shallow bowl lined with dead grass and down feathers. Egg-laying typically occurs from April to August. Average clutch size on Laysan Island is approximately four. The more recently established population on Midway lays larger clutches, presumably because of better availability of food. Ducklings are precocious and feed on their own day two after hatching, but are guarded, brooded, and led to foraging sites by the hen for approximately 40 to 60 days. ==Status and conservation==

Decline to near-extinction The decline of the Laysan duck began between AD 400 and 1000, with the colonization of the Hawaiian Islands by Polynesians and associated non-native mammalian predators. ==In popular culture==

In 2023 the Laysan teal was featured on a United States Postal Service Forever stamp as part of the Endangered Species set, based on a photograph from Joel Sartore's Photo Ark. The stamp was dedicated at a ceremony at the National Grasslands Visitor Center in Wall, South Dakota. == References ==