status: Vulnerable, IUCN Endangered, ESA
range: USA (Hawaii)
Description and biology
The Laysan finch is a songbird that averages 6 inches (15 centimeters) long. The plumage (covering of feathers) differs between females and males of the species. In females, the upper plumage is brown, marked by black streaks tinged with yellow-green. The breast is light yellow, and the abdomen and tail are dull white. All underparts have brown streaks. In males, the head, throat, and breast are bright yellow during breeding season. The upper back is yellow-green with broad black streaks. The lower back is gray. The black wings and brown tail are edged with yellow-green. Both sexes have a heavy, gray bill.
Laysan finches have a varied diet. They eat seeds, shoots, flowers, fruits, seabird eggs, and insects and their larvae.
Breeding season for Laysan finches extends from April to June. The birds build their nests in clumps of bunchgrass 4 to 17 inches (10 to 43 centimeters) off the ground. After laying 3 eggs, the female incubates (sits on or broods) them for about
16 days. The young chicks fledge (develop flying feathers) in just over a month.
Habitat and current distribution
The Laysan finch is native to Laysan Island, an islet (very small island) of the Hawaiian Islands, located about 750 miles (1,200 kilometers) northwest of Niihau Island. It has also been introduced to nearby Pearl Island and Hermes Reef, as well as other small islands in the area. Biologists (people who study living organisms) estimate the Laysan Island population to be at least 10,000. Between 500 and 1,000 Laysan finches exist on the other islands.
On Laysan Island, the finches inhabit sand dunes around the coastline and a brackish (mixture of freshwater and salt water) lagoon in the center of the island.
History and conservation measures
Early explorers to the region believed the Laysan finch's pleasing song made it an attractive cage bird. At the beginning of the twentieth century, as many as 4,000 of the birds may have inhabited Laysan Island.
In 1903, rabbits were introduced to the island. They quickly ate most of the natural vegetation, destroying the habitat and food supply of the island's native birds. In 1909, U.S. president Theodore Roosevelt designated Laysan Island and other islands in the Hawaiian chain as part of the Hawaiian Islands Bird Reservation. However, this move did little to stop the decline of the Laysan finch population. In 1922, when the last rabbits were finally removed from the island, only about 100 of the finches remained.
Despite its growing numbers, the Laysan finch is still considered vulnerable. Introduced predator species, such as rats, could still easily wipe out the birds. Diseases carried by introduced birds could also destroy the finch population.
Laysan Island is now part of the Hawaiian Islands National Wildlife Refuge. This limits the number of humans allowed to visit the island, providing further protection for the Laysan finch.