No Evidence of Interspecific Competition Regulating the Urban Avian Communities of the Kanto Region, Japan

Abstract To assess the impact of urban sprawl on avian biodiversity, many studies worldwide have tackled the question of which birds are able to inhabit urban areas. Some studies have suggested that ecological characteristics of birds are important. Other studies, however, have suggested that interspecific competition can regulate urban avian communities. In order to examine whether interspecific competition is primarily responsible for community structure, we investigated the degree of cooccurrence of ecologically similar species in the urban avian community in the Kanto region of Japan. They should not coexist if interspecific competition is strong. On comparing the observed avian community with virtual communities, we did not obtain any evidence of interspecific competition regulating the urban community. The main mechanism behind formation of an urban avian community structure appears to be the ecological traits of the species.