data nocturnal departure time and sun elevation

There are ten columns: 1. “dep.min.sunset”: This variable details the individual nocturnal departure timing in minutes after sunset. 2. “sunele.dep.2”: This variable details the sun’s elevation at the moment of the nocturnal departure in degrees below the horizon. 3. “Sex”: "Sex": This is a factor with two levels. "1" says that the bird was a male and "2" that it was a female. 4. "Age.ad": This is a factor with two levels, i.e., "young" and "old". In autumn, "young" means 1st calendar year bird and "old" means that the individual was older than "young". In spring, "young" means 2nd calendar year bird and "old" means that the individual was older than "young". 5. "subsp": This is a factor with two levels. "leu" says that the bird belonged to the leucorhoa subspecies of the northern wheatear and "oen" says that the bird belonged to the oenanthe subspecies of the northern wheatear. 6. “season”: This variable indicates whether the bird was caught in spring or autumn. 7. “energystores_release”: This is a numeric variable and it provides the individual energy stores at release, estimated as detailed in eqn. 2 of the paper. 8. “year”: This variable indicates the year in which the bird was caught. 9. “jd_arr”: This is the day of year of capture with 1 Jan is 1. 10. “rho.act.dep”: We converted departure direction (circular variable) into a measure of deviance between observed (radio-tracked) departure direction and seasonally appropriate migration direction which enabled the inclusion of directional information in subsequent multivariate analyses, cf. Müller et al. (2018, Journal of Animal Ecology, https://doi.org/10.1111/1365-2656.12821 ). This measure of deviance, the resultant vector length ρ (rho; rho of departure direction), was calculated using the “circ.summary” function of the R package “circular”, for details see corresponding paper. It ranges from 1 (no deviance between observed departure direction and seasonally appropriate migration direction) to 0 (deviance of 180°).