Seabirds in the stomach contents of Black Rats Rattus rattus on Higashijima, the Ogasawara (Bonin) Islands, Japan

Marine Ornithology 37: 293–295 (2009) Eradication programs for invasive rodents have accelerated since pioneering efforts by New Zealand biologists in the 1970s to conserve not only seabird populations but also island ecosystems (Howald et al. 2007, Rauzon 2007). In Japan, Black Rat Rattus rattus eradication programs have been carried out recently in the Ogasawara (Bonin) Islands (Hashimoto 2009, Makino 2009). The Ogasawara Islands are known to be a sanctuary for birds, including several indigenous or endangered species such as Columba janthina nitens, Apalopteron familiare, Tristram’s Storm-Petrel Oceanodroma tristrami, Matsudaira’s Storm-Petrel O. matsudaira and Bonin Petrel Pterodroma hypoleuca (Chiba 1992). However, they are threatened by invasive mammals such as Black Rats, Norway Rats R. norvegicus and feral cats Felis catus (Kawakami 2002, 2008). Based on historical documents, Yabe (2006, 2008) estimated that Black Rats were introduced into the Ogasawara Islands in the 1910s, and Norway Rats and House Mice Mus musculus arrived more than 140 years ago. Despite their short history, Black Rats have expanded their distribution to more than 70% of islands and islets (Horikoshi et al. 2009), but Norway Rats and House Mice are known only on two islands (Kawakami 2002, 2008). SEABIRDS IN THE STOMACH CONTENTS OF BLACK RATS RATTUS RATTUS ON HIGASHIJIMA, THE OGASAWARA (BONIN) ISLANDS, JAPAN