Data associated with: "Egg discrimination along a gradient of natural variation in eggshell coloration" authors: Daniel Hanley, Tomáš Grim, Branislav Igic, Peter Samaš, Analía V. López, Matthew D. Shawkey, and Mark E. Hauber email: daniel.hanley@liu.edu These data represent the colours (quantum catch for long- (l), medium- (m), and short- (s), and ultraviolet-wave (u) sensitive photoreceptors as well the principal members of the double cones) of individual egg models presented to either blackbirds or the American robin. Responses (response) were either accept or eject. Flush represents whether the female was flushed from her nest at the time of model introduction. Clutch represents the clutch size. Laying date is the date of laying of the first egg laid (for complete details see text). Age represents the age of the nest, relative to clutch completion, at the time of model introduction.