| 要旨トップ | 目次 | | 日本生態学会第73回全国大会 (2026年3月、京都) 講演要旨 ESJ73 Abstract

一般講演（ポスター発表） P1-184 （Poster presentation）

#### How synchronized are migratory birds with vegetation green-up?【A】【E】

*Yi SHEN, Jamie M KASS（Tohoku Univ.）

The timing of seasonal biological events (phenology) is shifting globally in response to climate change. Many migratory birds track the spring green-up of vegetation to follow spatial and temporal peaks in food availability along their migration routes. However, birds may not perfectly synchronize with green-up at their destination because they cannot directly perceive local climatic conditions in advance. As climate change alters the timing of vegetation phenology, this imperfect tracking may lead to phenological mismatches. Although green-up synchrony for birds has been extensively studied in Europe and North America, empirical evidence from East Asia remains limited. Therefore, we asked: To what extent do migratory birds breeding in Japan adjust their migration timing in response to interannual variation in vegetation green-up, and does the strength of this synchrony vary among species and across dietary guilds? We compiled bird occurrence data across Japan from eBird and the Monitoring Sites 1000 dataset. Observations were aggregated to a 120-km hexagonal grid, and standardized effort filters were applied to ensure comparability among datasets. For each species, records were restricted to breeding-season observations within species-specific breeding ranges derived from eBird Status and Trends products. Annual migration timing was estimated from detection dates in grid cells. Vegetation phenology was derived from satellite data to quantify spring green-up timing during 2004–2022. Green-up metrics were averaged within grid cells and linked to migration timing. Responses varied substantially among species. While some short-distance migrants advanced migration in years of earlier green-up, many species exhibited weak or nonsignificant associations. Sensitivity to vegetation phenology was not uniform across taxa, and migration timing often showed greater interannual variability than corresponding green-up metrics. Such heterogeneous responses imply species-specific constraints in tracking climate-driven phenological change and may contribute to differential vulnerability among migratory birds in Japan.

日本生態学会