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Subject: | two birds added to red list of extinctions |
From: | |
Date: | Wed, 17 Nov 2004 18:06:30 EST |
to clarify, the hawaiian crow has been classified as extinct in the wild. the hawaiian thrush referred to was also known as the kama'o Myadestes myadestinus endemic to Kaua'i (see below). there is some good news, the Christmas Island Imperial pigeon has been upgraded from Critically Endangered to Vulnerable. the hawaiian thrush entry from the IUCL site www.iucnredlist.org/search/details.php?species=14031 Myadestes myadestinus was endemic to Kaua'i in the Hawaiian Islands (USA), where it was probably restricted to dense montane forest. It was the most common of the forest birds in 1891, but, by 1928, had disappeared from the lower altitudes and became restricted to dense montane forest in the Alaka'i Wilderness Preserve. During 1968–1973, its population was estimated at 337 individuals (±122 standard error) while, in 1981, an estimated 24 (±20) individuals were present. The last probable sighting was in 1989, since then there have been several unconfirmed reports, but no confirmed detections, despite numerous intensive surveys in areas formerly occupied, particularly in 1995 and 1997. It now seems appropriate to reclassify this species as Extinct as there seems little reasonable doubt that the last individual has died. However, it is worth noting the M. palmeri went many years without being seen, but then began to reappear in small numbers. Disease carried by introduced mosquitoes and the destruction and degradation of forests are likely to have been the chief causes of extinction. The advance of feral pigs into pristine upland forests degraded habitat and facilitated the spread of mosquitoes. Competition with introduced birds may have exacerbated the problems faced by this species. Deprived of lowland forest, the species was also exposed to the effects of hurricane damage of upland forest, which severely disrupted portions of native forest and allowed the germination and expansion of noxious weeds. Also potentially detrimental to the remaining suitable habitat are introductions of new alien invertebrates, such as the two-spotted leafhopper (Sophonia rufofascia), which may threaten many food plants of M. myadestinus. shane b vaucluse |
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