Which penguin species is the only one that regularly breeds on the Antarctic mainland?

The Adélie penguin is the only penguin species that regularly breeds on the Antarctic mainland.

Adélie penguins breed along the Antarctic coast and on nearby islands, returning during the austral summer when exposed ground is available for nesting. Their nests are simple piles of stones, and adults may carefully select or defend useful pebbles.

Emperor penguins also breed in Antarctica, but their colonies are established on stable sea ice rather than on the Antarctic mainland itself. This distinction is why the Adélie penguin is identified as the mainland-breeding species.

Adélie penguins are medium-sized, with a black head, white eye ring, and relatively short bill. Their scientific name is Pygoscelis adeliae, and the species was named after Adèle Dumont d’Urville, wife of the French explorer Jules Dumont d’Urville.