Fig. 7.

Effects of (a) fuel load, (b) cloud cover and (c) tailwind assistance on nocturnal departure timing (proportion of night at departure) obtained from two beta regression models (Tables 3 and 4). Shown are the respective model predictions (black lines) and the raw data (dots) for Northern Wheatears (light grey), European Robins (orange) and Common Blackbirds (dark grey). To illustrate the effects of fuel load, cloud cover and tailwind assistance we used the respective candidate models with the best fit (Additional file 1: Table S3). The remaining variables included in the respective model were set to their mean and species was not considered. Please see Additional file 1: Table S1 for original variation in fuel load and tailwind assistance