Nest-site selection of the Red-billed Leiothrix and Japanese Bush Warbler in Japan

Abstract

The Red-billed Leiothrix Leiothrix lutea has been introduced from China and is rapidly increasing in deciduous broad-leaved forests of Japan. We studied nest-site characteristics and nest-site selection of this species and the Japanese Bush Warbler Cettia diphone, a sympatric native species, in southwestern Japan. Both species placed nests exclusively in bamboo thickets and on bamboo stalks. The Red-billed Leiothrix built pendulous nests in the canopy of high concealment. The Japanese Bush Warbler placed nests on the crossing of bamboo stems and selected places of high stem density. The Japanese Bush Warblers placed nests in denser vegetation than the Red-billed Leiothrix. The segregation of nesting microhabitat was also evident in both species to coexist in bamboo thickets. Existence of few inhabitants in bamboo thickets may contribute to the invasion success of the Red-billed Leiothrix.