As penguins are birds, the female penguin lays eggs after mating. Most species of Emperor Penguin Eggpenguins build nest, the nest may consist only of small stones, pebbles and molted feathers, or hollows in the dirt. The color of the penguin eggs varies among species. Depending on the penguin species the eggs may be white to bluish or greenish. The shape and size of the eggs varies among penguin species, some are more round and some are pear-shaped.
Only six species of penguin breed in the Antarctic: the Emperor, Adelie, King, Gentoo, Chinstrap, and Macaroni penguins.
A nest of penguin eggs is called a clutch. Clutches usually contain two eggs. Emperor and king penguins lay only one egg. After the female penguin lays her eggs, she will return to the ocean to feed and gain back her body weight. Both the male and female penguins take turns sitting on the eggs (incubating) until the eggs hatch. When penguin chicks hatch most are covered in a fine down. The down feathers of different species may be white, gray, black, or brown.