Dataset behaviour plasticity of birds

Bird species subjected to more variable environments should have greater phenotypic plasticity than those that are more restricted to specific habitat types leading to the expectation that migratory birds should be relatively more plastic than resident birds. For each bird species, we collected the following life-history data: Species body mass and habitat breadth were extracted from Sayol et al., 2020 while diet breadth, life span (max) were extracted from Sayol et al., 2018 and migratory status (resident or sedentary, partially migratory or migratory) was extracted from Tobias and Pigot, 2019. The main type of diet for each species was extracted from Wilman et al., 2014.

We calculated the mean, maximum, minimum and standard deviation of flight initiation distance for each bird species with > 5 observations, to avoid potential overinflated standard deviation estimates from species with only a few observations. Then, for each species, we calculated our metric of plasticity based on the coefficient of variation (CV) of FID. Because this is a ratio of the variance to the mean, plasticity is independent of body size.

Methods
Following standardised methods, trained observers identified a non-alarmed bird (i.e. resting or foraging) and directly approached at a measured pace of 0.5 m/s. With such data, we processed and estimated a surrogate of behavioural plasticity. The behavioural plasticity was calculated for each bird species, based on the coefficient of variation (CV) of FID.