From sky to ground: decoding migratory bird’s habitat selection along the multi-scale sequence

Migratory birds select habitats by observing landscape patterns at different scales as they descend from higher elevations, weighing habitat availability. Understanding how this selection process operates at multiple scales and how decisions at different scales interact is crucial for identifying the optimal scale for efficient habitat conservation. We aimed to investigate the regularity of changes in migratory birds’ habitat selection in response to landscape variables over multi-scales, using the Oriental White Stork (Ciconia boyciana) as an example. We developed Scale Response Models and Habitat Selection Models using a sequence of nine scales (5–200 km) within the East Asian-Australasian Flyway to evaluate the stork’s scale-sensitivity and assess the change of explanatory power of landscape variables across scales at different periods. Scale-sensitivity of storks was highest during the wintering period. The explanatory power of the suitable habitat indicator is higher at larger scales, but decreases with decreasing scale; while the opposite is true for the unsuitable habitat indicator. At large scales, wetland indicators dominated in breeding period, while water indicators dominated in other periods; at smaller scales, unsuitable habitat indicators had stronger impacts in wintering period. We revealed a nested relationship in multi-scale habitat selection among storks: “benefit-tendency” decisions at larger scales provide context and constraints; “risk-avoidance” decisions at smaller scales determine settlement. Due to internal and external factors, migratory birds displayed different scale-sensitivities and landscape preferences across periods. Our findings highlight the scale-dependence of organisms’ behavior and landscape characteristics, providing guidance for multi-scale habitat conservation.