Breeding in Adélies

Breeding takes place between October and February each year.
Young Adélies don't visit breeding colonies until they're 2 to 4 years old. Initial visits are to claim a nest site.
Adélies first breed at 3 to 6 years of age. The average is 5 years for females and 6 for males.
96% of Adélies return to their natal colony (where they were born), to breed for the first time. Most (67%) nest within 200 m of where they were born. This strong tendency is called natal philopatry. Some individuals do move to other or new colonies, however.
Nesting occurs in noisy communal colonies of between 100 to 250 000 pairs.
Colonies are located close to regions like polynyas and local up-wellings that provide accessible food.
To avoid problems with snow and melt-water, nests are built of small stones on sloping ice-free ground.
Parents share the job of raising chicks almost equally.
Up to 40 foraging trips are needed by parents to raise a single chick.
Fecundity of breeding pairs averages 0.9 chicks/year.
Up to 10% of chicks are not sired by the attending male.