These pics are courtesy of Jacob Hadomi in Israel and are of his pair of Olive Pigeons. He states that the pair are about 5 years old. The "eye cere" coloration may be due to the breeding condition of the birds - instead of an actual "dimorphism" between the sexes.
In some species the eye ceres of the male enlarges and darkens with color when in breeding condition and courting the female.
As seen in the pics there may also be a "coloration" difference of the plumage between the sexes.
Visit Jacob Hadomi's page showing the juvenile dimorphism