Phenological tracking of migratory waterfowl to spring green-up derived from individual movement

Migratory birds are affected by phenological mismatches between migration timing and food availability under climate change. Birds can adjust their migration timing to some extent to track shifts in food availability, a phenomenon referred to as phenological sensitivity. Our understanding of species-specific phenological sensitivity and tracking in response to climate change remains limited, particularly because these processes have rarely been quantified using long-term individual movement data.

In this study, we investigated the phenological tracking of migratory waterfowl by combining eight-year satellite tracking data of four species with spring green-up derived from remote sensing. Using Bayesian models and accounting for individual differences, we analyzed changes of bird arrival timing in relation to multi-year shifts in spring green-up, as well as responses to interannual variation.

Birds respond to shift in spring green-up with species-specific differences. Species with intermediate levels of individual variation (the greater white-fronted goose Anser albifrons) tend to align their migration timing better with both multi-year and interannual shifts in spring green-up, whereas species with excessive individual variation (the tundra bean goose Anser serrirostris) show limited degree of phenological tracking.

Migratory waterfowl respond to both multi-year and interannual shifts in spring green-up, with individual variations influencing species-specific tracking. While intermediate individual variation may lead to more synchronous responses to climate change at the population level, excessive individual variations may reduce population-level synchrony and hinder adaptive response. Our findings advance the understanding of climate change impacts on migratory birds and their capacity to adapt to changing environments. Considering individual variation in phenological tracking is therefore essential when assessing species' vulnerability to climate change.