Rockhopper Penguin

Rockhopper Penguin – Eudyptes Chrysocome

Eudyptes Genus – Crested penguins
Height: 19-22 in.
Weight: 5-10.0 lb.
Subspecies: Eudyptes chrysocome chrysocome, Eudyptes chrysocome filholi
Eudyptes chrysocome moseleyi.
* Some scientists only recognize two subspecies, discarding the filholi.
Life expectancy in the wild: 10-15 years.
Approximated Population: 3.6 Million
Population tendency: Decreasing
IUCN Conservation status: VU
IUCN Conservation Status: EN (North subspecies)

There is some disagreement among scientists about the subspecies of the Rockhopper penguin. Some scientists think that the Northern Rockhopper is a subspecies of the southern and that the southern is divided into east and west while others believe that they all are only variations of the same species.

Appearance

Although very similar to other crested penguins, Rockhopper penguins have a unique crest design as well as a characteristic color of their iris. They have red eyes and a white line contours the base of their beak.

Their bright pink legs contrast with the rest of the black and white plumage.

They have red eyes and a white line contours the base of their beak.

Southern Rockhopper penguins are the smallest of the crested penguins and third smallest of all penguin species. Some individuals, especially from the northern subspecies, feature more disheveled crest while the ones from the south and east keep it shorter and sparse.

Their flippers are strong, rigid and narrow, while their eyes are small and dark red, which blend in with the black plumage.

Hatchlings are dark brown with white and do not exhibit the characteristic yellow crest of the adults.

Where do they live?

Their habitat is usually vast green pastures and rocky areas. Southern Rockhopper penguins colonies are in southern regions of Chile, the Falkland Islands, and Southern Argentina while the northern subspecies inhabit only the Gough Island, Tristan da Cunha archipelago, and Amsterdam Island. The eastern subspecies main colonies are on several islands including Crozet Island, Kerguelen Islands, Marion Island, Heard Island, Macquarie Island, Campbell Islands, Auckland Islands and Antipodes Islands.

Rockhopper – Crested penguins.

Skills and Behavior

They are very nervous and temperamental. Clashes between individuals are common; flippers, beaks, and aggressive sounds are typical in these conflicts.

The vocalization sounds they make are quite loud and divide into four categories according to their purpose: contact, sexual, warning, and recognition of hatchlings.

Like all penguins, they can rest on their bellies, but they cover their faces with their flippers while resting on a rock or some place that they consider comfortable.

They walk freely in populated areas of sea lions without showing any fear, but in the water, the behavior of both is entirely different. They usually jump into the sea from low-rise rocks.

They are dedicated hunters who manage to dive to a depth of 144 ft and repeat 15 to 40 submersions per hour.

Molting

The pre-molting trip is longer than other species of penguin; up to 60 days for northern species and 30 days for the southern one. Young or non-breeding individuals begin molting in January and February while the rest in mid-March. They stay on the coast during the 25 days of the whole molting process. Once the new feathers cover their body, they return to the ocean.

What do they eat?

Crustaceans such as krill, cephalopods and fish are the most common prey for southern rockhopper penguins, while the ones from the north prefer squid. They efficiently adapt to the changing conditions of the area they inhabit, like the depth of the ocean or the prey available and according to this, manage their energy expenditure.

Characteristics of Rockhopper penguins.

Reproduction

Incubation period: 33 to 35 days.
Normal clutch: Two eggs.

Males are the first to arrive at the nesting colonies while females do it one week later. There are not exact dates for this as their extensive distribution, and the conditions of each place set a different time for each zone.

Both parents are responsible for incubating the two laid eggs.

While males wait for their partners, they claim last year’s nest and cover it with new material. When the females show up, the process of courtship begins, being an indicator of acceptance when the female starts to organize the new material that the male deposited in the nest.

Both parents are responsible for incubating the two laid eggs. The second egg is usually 30% larger than the first, but as they are not able to feed both chicks once they are born, they let the first and visibly smaller hatchling to die.

They sometimes adopt an additional third egg, but they do not give it any attention and usually dies.

Threats

Scientists have linked aggressive behavior in Rockhopper penguins with changes in the ocean temperature and acidification.

Human actions have affected some colonies of penguins like those in the Landfall Island in Chile, formerly home to thousands of this kind of penguins, but today there is not a single one nesting there. In the past, egg harvesting was very common, although today is not allowed anymore. Oil spills, commercial fishing, and introduced animals are other problems affecting the populations of this species.