29 Invasive Birds in Japan Kazuhiro EGUCHI 1 and Hitoha E. AMANO 2* 1 Department of Biology, Faculty of Science, Kyushu University Fukuoka 812-8581, Japan. E-mail: kegucscb@mbox.nc.kyushu-u.ac.jp 2 Graduate School and Cultural Studies, Kyushu University, Ropponmatsu, Fukuoka 810-8560, Japan * Present address: WWF Japan, 3-1-14 Shiba, Minato-ku, Tokyo 105-0014, Japan Abstract Introduction of exotic birds has been increasing throughout the world. We conducted inquiry investigations in order to reveal the spread of introduced bird species in Japan. Forty-three exotic species are known to breed or are regarded as breeding. The Feral Pigeon (Columba livia), Chinese Bamboo Partridge (Bambusicola thoracica), Red-billed Leiothrix (Leiothrix lutea), Budgerigar (Melopsittacus undulatus) and Red Avadavat (Amandava amandava) are widely distributed. The Rose-ringed Parakeet (Psittacula krameri manillensis), Common Peafowl (Pavo cristatus), Light-vented Bulbul (Pycnonotus sinensis), Melodious Laughing Thrush (Garrulax canorus), Crested Myna (Acridotheres cristatellus) and Black-billed Magpie (Pica pica sericea) are locally common, though they have limited ranges. Sightings of other species were sporadic and regionally limited. Most of introduced birds in Japan are escaped caged birds. About two thirds are from tropical regions, and show diet generalism as omnivores, granivores and frugivorous or herbivorous insectivores. Light-vented Bulbuls, Feral Pigeons and Common Peafowl exerted crop damage. Although adverse effects by exotic birds are not prominent yet, there is great concern that exotic birds will become a threat to native biota and habitats in future. Key words: introduced birds, invasive birds, naturalization 1. Introduction Disturbance of native biota and devastation of local ecosystems are major adverse effects caused by invasive species. Nile perches prey upon native fishes and have changed the fauna of Lake Victoria remarkably (Hunter, 1996). Goats, cattle and pigs destroy the habitat of islands (Pimentel et al., 2000). Introduced carnivorous mammals, including rats, cats, mongooses and weasels, have caused local extinction of native bird species in the Hawaiian Islands, New Zealand and other oceanic islands (Pimentel et al., 2000; Levy, 2003). Many birds have also been trans- ported by humans to new areas of the world. The ecological effects of introduced birds on native biota and ecosystems are known, and some are harmful (Long, 1981; Lever, 1987). The introduction process is composed of three phases; arrival or entry, establishment and integration (Vermeij, 1996). A population may increase after establishment and proceed into the integration phase, where the species interacts with the recipient commu- nity and, eventually, is integrated into it. Increasing population of exotic species can exert a negative influence on local ecosystems and native biota. In general, biotic invasion causes disturbance or destruc- tion of habitats and ecosystems, and decline or extinction of native biota (Long, 1981; Lever, 1987). Risk assessment is a tool for decision-making on whether or not a species is to be introduced or imported and for establishing eradication or regulation programmes against established invasive species (Wittenberg & Cock, 2001). It assesses the rate of entry, likelihood of successful introduction, rate and extent of spread, and economic and ecological impact. However, because no effective methods of assessing the risk of entry, establishment and spread of potential invasive species have been established yet, risk assessment schemes have been practiced in only a limited number of countries (Wittenberg & Cock, 2003). In Japan, the Ministry of Environment formu- lated a new Biodiversity Strategy in 2002 (http:// www.biodic.go.jp/nbsap.html). It includes three main actions in response to biotic introduction: Global Environmental Research ©2004 AIRIES 8(1)/2004: 29-39 printed in Japan