Relationships between Flight Initiation Distance (FID, in meters) and functional predictors. These include A urban-rural gradient B absolute latitude C altitude, and D introduction lag. Raw data are plotted in all figures, instead of the model predicted leverages. When fitted in a full mixed model, starting distance (shown in Fig. 4A), introduction lag (years ago from 2023), absolute latitude, and urbanization were significantly associated with FID, while altitude above sea level was not. Shaded areas represent 95% CIs of the significant slopes.