Laysan finch

Psittirostra cantans

TAXONOMY

Psittirostra cantans Wilson, 1890. OTHER COMMON NAMES

French: Psittirostre de Laysan; German: Laysangimpel; Spanish: Certiola de Laysan.

PHYSICAL CHARACTERISTICS

6-6.5 in (15-18 cm). Bill large and parrotlike, tip of upper mandible forms slight downward hook. Adult males have bright yellow head, throat, and breast; lower back and rump grayish brown, abdomen whitish, gray collar around neck. Females less gaudy, dark streaks in yellowish crown, some streaking on flanks, gray collar, yellowish throat and breast, dark brown spots along back.

DISTRIBUTION

Laysan Island and Pearl and Hermes Reef, a coral atoll; both sites part of a long string of such islets northwest of main Hawaiian Islands. Shares both sites with nesting seabirds.

HABITAT

Laysan is a low-lying, sandy island about 1,000 acres (405 ha) in area; no trees, but abundant shrubbery and grasses. Pearl and Hermes Reef is a coral atoll containing several small islands.

BEHAVIOR

Lively and gregarious; do not fear humans, will even eat food out of hands of observers.

FEEDING ECOLOGY AND DIET

Omnivorous. Feed on carrion, insects, seeds, roots, sprouts, soft parts of plants and seeds, and interiors of tern eggs, whose shells it punctures with its beak to reach the soupy innards.

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Psittirostra cantans

Resident

At beginning of the breeding season, males gather and display to females in groups resembling leks. As Laysan has no trees, finch secures cup-shaped nest of grass and twigs in clumps of grass or in small bushes.

CONSERVATION STATUS

Listed as Endangered by the USFWS and the State of Hawaii, and as Vulnerable by the IUCN. Habitat is vulnerable to violent storms and the proliferation of alien species. Nearly became extinct in the 1920s. Population had declined to about 100 individuals in 1923, but diet of carrion and seabird eggs helped them to survive.

SIGNIFICANCE TO HUMANS

Significance lies in the successful efforts of wildlife biologists to preserve the species, and in the implications for the study of adaptive evolution. Biologists transferred 108 birds from Laysan to Pearl and Hermes Reef in 1967. In less than 30 years, the beaks shortened in accordance with their new food sources, demonstrating how quickly species can physically change in adapting to a local environment. About 350 birds survive at Pearl and Hermes. ♦

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