89 Monitoring of Avifauna to Estimate the Effect of Ecological Restoration in Mukojima, Bonin Islands Monitoring of Avifauna to Estimate the Effect of Ecological Restoration in Mukojima, Bonin Islands Naoko Emura 1, * , Wataru Furuya 2, 3 , Haruko Ando 4 and Tomohiro Deguchi 5 Abstract. Mukojima (Muko Island) of the Bonin Islands, Japan, has undergone multi- ple ecological changes as part of ecological restoration projects, such as the eradication of in- vasive species. However, the effect of these projects on the resident terrestrial birds of Mukoji- ma are unknown. In this study, we performed censuses in two transects to record quantitative data of resident terrestrial bird species of Mukojima. In addition, all bird species observed from February to May 2008‒2012 were also recorded. Only two species, the Blue Rock Thrush Monticola solitarius and the introduced Japanese White-eye Zosterops japonicus were regularly observed. There were no changes in abundance of either species between 2007 and the present study, except for an increase in the Blue Rock Thrush along one transect. We ob- served a total of 74 bird species, 32 of them newly recorded on Mukojima. Although prelimi- nary, our results contribute to an understanding of the effects of ecological restoration on the avifauna of Mukojima. Key words: Blue Rock Thrush, Bonin Islands, Japanese White-eye, Mukojima, Rat eradication. キーワード ： イソヒヨドリ，小笠原諸島，メジロ，聟島，移入種ネズミの駆除． Because oceanic islands often have no native mammals other than bats, native bird spe- cies probably lack adaptations that allow them to coexist with introduced mammals, making them more vulnerable to such disturbances. Eradication of introduced mammals has been con- ducted on many islands around the world, and preliminary signs of recovery have been seen in seabirds (Kawakami et al. 2010, Bourgeois et al. 2013, Whitworth et al. 2013) and terres- trial birds (Buckelew et al. 2011). However, full recovery of bird populations may take a long time. Van Vuren (2013) reported that a clear recovery of the population of terrestrial birds on Santa Cruz Islands was only observed about 20 years after exotic mammal eradication. There- fore, it is important to continuously monitor the effects of introduced mammal eradication on island avifaunas. The Bonin Islands are a chain of oceanic islands, located 1,000 km south of the Japanese 89 山階鳥学誌 （J. Yamashina Inst. Ornithol.）， 46: 89‒100, 2015 ©Yamashina Institute for Ornithology Short Note （短　報） Received 23 February 2014, Revised 11 October 2014, 2nd Revision 25 November 2014, Accepted 9 December 2014. 1 Department of Life Science, Rikkyo University, Nishi-ikebukuro 3‒34‒1, Toshima-ku, Tokyo 171‒8501, Japan. E-mail: emurako@yahoo.co.jp 2 Ogasawara Ecotourism Resort, Higashimachi, Chichijima, Ogasawara, Tokyo 100‒2101, Japan. 3 Present address: Oosaki 1‒2, Bando, Ibaraki 306‒0622, Japan. 4 Graduate School of Agriculture, Kyoto University, Kitashirakawa-oiwake-cho, Sakyo-ku, Kyoto 606‒8502, Japan. 5 Yamashina Institute for Ornithology, Abiko, Chiba 270‒1145, Japan. * Corresponding author