Order: Penguin, Family: Penguin, Genus: Macaroni Penguin

Length: 40–58 cm

Male: 4.2 kg, Female: 3.6 kg (before molting)

Male: 2.3 kg, Female: 2.1 kg (after molting period)

Population: Approximately 2.5 million (for the Southern Rockhopper Penguin)

Rockhopper Penguins are generally referred to as 'Rockhopper Penguins' in English, but this page will primarily use the Japanese name. Furthermore, Rockhopper Penguins are divided into three types: Southern, Eastern, and Northern, which have been considered subspecies. However, recent treatments increasingly regard these as separate species.

The appearance of the Rockhopper Penguin includes black cheeks and throat, while the underside is white. The backside is covered with black feathers, and the surface of the feet is pink, while the underside is black. A horizontal brow-like stripe extends above the eyes, making it look like the penguin has eyebrows. From there, beautiful yellow crest feathers flow backward, and the beak is an orange-red color. Males and females look identical, making it difficult to distinguish between them, but males are generally larger.

Rockhopper Penguins come ashore on various islands, including the Falkland Islands, around October-November to breed, forming groups known as rookeries. The location is typically flat or sloped vegetation-surrounded areas near the coast, though some islands feature rookeries at cliff tops.

Nest building occurs in the same locations using primarily grass and pebbles, and these nests are reused and repaired in subsequent breeding seasons. After completion, breeding commences with vocal confirmations between mutually attracted partners. The bond between pairs is said to be strong.

Females lay two eggs around November-December, and males and females take turns incubating them. As hatching approaches, the male ventures out to sea to gather food for the upcoming chicks. During this time, the female continues to incubate, enduring nearly 20 days without food or drink, a challenging period. Once this incubation period (about 32-34 days) is successfully concluded, the chicks are born.

For the first 24-26 days after birth, the male remains primarily by the nest, while the female goes to sea to forage and feeds the chicks. As the chicks grow, they are left in communal nurseries called crèches.

Parents continue to forage at sea and feed the chicks in turns. The chicks grow to the size of adults within about 65-75 days and then leave the nest. The timing of fledging typically occurs around February, although in northern islands, it can happen between December and January.

The fluffy down that initially covers the chicks gradually falls out and is replaced with feathers, including the distinctive adult crest feathers, though the young birds' crests remain somewhat smaller. As they mature, their crest feathers develop fully.