Because penguins are birds, they must breed on land.

Because penguins are birds, they must breed on land.. . , All birds lay eggs and incubate them until they hatch. For penguins, sitting on a nest keeping eggs warm and dry is problematic because to do so, they must temporarily leave the ocean. African penguins gather in breeding colonies on rocky, offshore islands and along Africa's southwest coast. Leaving the ocean means leaving their food source. To keep from starving while nesting, African penguin pairs take turns. While one incubates the eggs, the other is at sea, foraging. The adult at sea eats for two. Within days, it returns to the nest, swaps places with its hungry mate, and feeds the chick., Let's eat! , A hungry chick knows how to get its parent's attention! It calls plaintively and pecks at the base of its parent's beak. This encourages the adult penguin to open its bill. The chick then pushes its bill far down the parent's throat, stimulating the parent to regurgitate all those fish it just ate at sea., Survival in the Wild , Collecting Penguin Eggs for Profit , Beginning late in the 19th century, a human taste for African penguin eggs turned commercial. Profit seekers began scouring breeding colonies and removing millions of eggs each season, which resulted in millions of unborn chicks. Until the late 1960s, when the practice was legally banned, the collection of AFrican penguin eggs continued unchecked, contributing to an overall population crash from which the species has yet to discover., Maryland Zoo Connection , Breeding Success at the Maryland Zoo , The African Penguin colony at The Maryland Zoo started in 1967 with 15 breeding pairs. It has since become the largest and most successful breeding colony in North America. Its impact on the AZA's African Penguin Species Survival Plan is extraordinary., More than 950 chicks have hatched at The Maryland Zoo, about 10 times more than any other zoo or aquarium, and nearly 600 have joined colonies at other zoos and aquariums.