ムシクイ類３種の秋の渡り時期の違い

Abstract

The difference of migration timing during the autumn migratory period of three leaf warblers of the genus Phylloscopus, breeding widely in Japan, was studied at two areas of Honshu Island, Japan; Nobeyama plateau in Nagano Prefecture, central Honshu and Mt. Rokko in Hyogo Prefecture, about 340 km west-southwest from Nobeyama plateau. The three species of leaf warbler were captured by mist-net from late July to early or late November over a five year period (2003-2007). The Eastern Pale-legged Leaf Warbler Phylloscopus borealoides and the Eastern Crowned Leaf Warbler P. coronatus were captured almost exclusively from late July to early September, whereas the Arctic Warbler P. borealis was captured from early September to late November. The trapping period of the former two warblers overlapped greatly, but the median period of the Eastern Pale-legged Leaf Warbler was earlier than that of the Eastern Crowned Leaf Warbler at Mt. Rokko. The slight overlap of fall migration timing between the Arctic Warbler and the other two warblers may be related to the latitude of breeding ranges of the respective warbler species.