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WatchList Species Account for Laysan Finch (Telespiza
cantans)
The Laysan Finch is naturally restricted
to the remote island of Laysan in the Hawaiian Islands National
Wildlife Refuge, with a small introduced population on Pearl
and Hermes Atoll; an introduced population at Midway Atoll
was extirpated by rats around 1944. At present the population
fluctuates around a mean of some 11,000 individuals. In the
early 20th Century, the population was severely impacted by
the depredations on the island’s vegetation by introduced
European rabbits at which time the finch population declined
to as few as 100 individuals; once the rabbits had died off
from starvation, the finch recovered its numbers. An omnivorous
species, it apparently survived the lean times of the rabbit
infestation by eating bird eggs of the marine birds nesting
on the island, persistent seeds, and carrion; two other endemic
passerines that depended on insects and nectar became extinct
during this ecological crisis, as did a nonpasserine, the
Laysan Rail.
The bird is excessively tame and trusting
and can be captured by hand. Laysan is a flat, sandy island,
about 400 ha in size. In the interior is a large, shallow,
hypersaline lake with mudflats. The finch uses all the plant
associations on the island. No predators are established on
the island but occasional visiting raptors take finches. Extreme
weather causes nest failure and direct mortality and the population
size is regulated primarily by weather. Introduction of disease
or predators such as rats to the island could have a devastating
effect on the bird. Alien plants degrade the habitat, and
several plant species did not reemerge once the rabbits were
gone. One alien plant, sandbur, was the subject of an eradication
effort after researchers found it was displacing vegetation
on the island, including the bunchgrass in which the finch
nests. Like the Nihoa Finch, the Laysan Finch is a member
of the Hawaiian Honeycreeper subfamily. The bird is listed
as federally endangered and as vulnerable under IUCN - World
Conservation Union Criteria.
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