The Siberian weasel, Mustela sibirica, which was introduced onto Miyake-jima Island, preys on eggs and chicks in the nest, and appears to have caused a significant decline in the number of Izu thrushes. Nest predation by large-billed crows, Corvus macrorhynchos, has also increased due to raw garbage becoming a more familiar sight in the Izu Islands, and domestic cats also prey on nests and fledglings. The impact of predation has been compounded by the ubiquitous threat of habitat loss. On many of the Izu Islands, natural forest has been destroyed for timber production, road construction and tourism development (3) (4). An additional, natural threat is volcanic eruptions on Miyake-jima. An eruption in 2000 covered the island in a fine layer of ash, killing many forest-dwelling insects. This does not appear to have affected the Izu thrush to the same extent as other birds on the island, but the emission of deadly gases from the volcano crater could still prove to have a damaging effect on Izu thrush populations (3).