Navigating a dynamic winterscape: habitat composition and individual variability shape daily movement in wintering common cranes in western India
Wintering migratory birds must balance energetic requirements, resource availability, and disturbance in increasingly human-modified landscapes. However, individual-level variability in daily movement and winter space use remains poorly understood in populations of the Common Crane wintering in South Asia. We investigated how seasonal dynamics, landscape composition, and individual differences structure winter movement ecology in a semi-arid agro-wetland system in western India. We analysed high-resolution GPS telemetry data from four tagged cranes tracked across three consecutive winters. Daily movement distances were modelled using mixed-effects approaches to partition variance within and among individuals and among winters. Daily movement trajectories were evaluated using non-linear temporal terms. Landscape predictors, including the proportion of cropland, built-up area, and habitat heterogeneity, were incorporated to assess environmental drivers. Winter utilisation distributions were estimated using dynamic Brownian bridge movement models. Daily movement distance followed a non-linear seasonal pattern consistent with shifts in the profitability of agricultural resources over winter. Cropland proportion and landscape evenness were negatively associated with movement distance, whereas a high proportion of built-up areas increased daily movement distance, reflecting a trade-off between resource concentration and anthropogenic disturbance. Winter utilisation distribution size varied markedly both within individuals across years and among individuals within seasons. Winter movement and space use in Common Cranes are predominantly context-dependent and environmentally driven. Seasonal dynamics, agricultural landscapes, and human disturbance jointly structure movement patterns, with limited but consistent individual differences. While limited by sample size, this multi-year, individual-based telemetry provides insight into winter spatial strategies of Common Cranes in dynamic semi-arid agro-wetland systems.