There is little distinction between male and female African penguins, although the male is slightly larger and has a longer bill than the female. Penguins are usually about 4 years old when they begin breeding. African penguins will remain with a single partner for many years, producing one or two eggs a year. They only separate normally if breeding has failed for some reason. They can breed at any time of the year, but the Boulders population tends to breed in March to May.