StudySite: name of the study site
Nestbox: Unique ID for each nestbox
DateColl: date of egg collection (Julian date)
LayingSeq: laying sequence (1 = first-laid egg)
ID_egg: Unique ID for each egg
Area_tot_L: total area of the egg in cm2 (lateral view)
Perim_tot_L: perimeter of the total area of the egg in cm (lateral view)
N_spot_L: the number of spots on the eggshell (lateral view)
Area_spot_L: total area of the eggshell covered with spots in cm2 (lateral view)
Perim_spot_L: perimeter of the area of the eggshell covered with spots in cm (lateral view)
Area_tot_C: total area of the egg in cm2 (crown region)
Perim_tot_C: perimeter of the total area of the egg in cm (crown region)
N_spot_C: the number of spots on the eggshell (crown region)
Area_spot_C: total area of the eggshell covered with spots in cm2 (crown region)
Perim_spot_C: perimeter of the area of the eggshell covered with spots in cm (crown region)
Area_tot_foot: total area of the egg in cm2 (foot region)
Perim_tot_foot: perimeter of the total area of the egg in cm (foot region)
N_spot_foot: the number of spots on the eggshell (foot region)
Area_spot_foot: total area of the eggshell covered with spots in cm2 (foot region)
Perim_spot_foot: perimeter of the area of the eggshell covered with spots in cm (foot region)