Duck, Laysan

Anas laysanensis

phylum: Chordata

class: Aves

order: Anseriformes

family: Anatidae

status: Vulnerable, IUCN Endangered, ESA

range: USA (Hawaii)

Description and biology

The Laysan duck is a relative of the more well-known mallard duck. An average Laysan duck measures 16 inches (41 centimeters) long. Its plumage (covering of feathers) ranges in color from light to dark brown. A white patch surrounds the duck's eyes and extends to its ear openings. The male (called a drake) has a green bill, while the female (simply called a duck) has a brown one. Both sexes have a purplish-green patch surrounded by white and black feathers on their secondary wing.

Relatively tame, the Laysan duck flies only short distances on the island it inhabits. Nocturnal (active at night), it feeds in lagoons on insect larvae and small crustaceans (group of animals including lobsters, crabs, and shrimp).

The breeding season for Laysan ducks lasts from February to August. After building a nest on the ground within clumps of grass, a female Laysan duck lays at least 3 pale green eggs.

Although the incubation for Laysan duck eggs is unknown, it is probably between 28 to 30 days.

Habitat and current distribution

Laysan ducks are found only on Laysan Island, which is an islet (very small island) of the Hawaiian Islands, located about 750 miles (1,200 kilometers) northwest of Niihau Island. The ducks prefer to inhabit the island's lagoons and marshes. Biologists (people who study living organisms) estimate the Laysan duck population to be 500.

History and conservation measures

The Laysan duck population declined for two reasons. The first was human hunting for food and sport. The second—and more serious—was habitat destruction. At the beginning of the twentieth century, rabbits were brought to Laysan Island. They quickly consumed most of the vegetation on the island, destroying the ducks' nesting grounds. By the time the rabbits were eliminated from the island in the 1920s, the ducks had become almost extinct.

As vegetation on the island recovered, so did the Laysan duck population. By the late 1950s, it had grown to almost 600. The current stable population of 500 seems to be the number the island's habitat can comfortably support.

Laysan Island is a part of the Hawaiian Islands National Wildlife Refuge. Human access to the island is strictly prohibited. Recent efforts to introduce the duck to other nearby islands have failed. Because its limited, fragile habitat cannot tolerate changes, the Laysan duck will always be considered threatened or vulnerable.