Miyamoto, T.; Kondoh, M.

Climate change is significantly affecting animal distributions and phenology, with migratory birds experiencing notable shifts in migration timing. There are complexities to changes in migration timing, considering variations due to monitoring locations or definitions of migration timing. Previous studies have focused on differences between traits in the magnitude of change and agreed that migration distance has an effect, although distribution has not been considered. This study investigates the factors influencing phenological changes in spring migration, focusing on First Arrival Date (FAD) and Last Departure Date (LDD) in eastern Japan. Using community science data from Sendai and Tokyo, we examine the effects of species characteristics, including trophic level, migration distance, and breeding and wintering areas, in addition to climatic variables. Consistent with other studies, FAD was advanced and LDD was delayed with climate. Notably, the magnitude of change in FAD differed depending on the distribution of wintering areas. Birds use many areas during their life cycle, and our results suggest that distribution, as a simple indicator, may be key to predicting responses to climate change.