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9/19/21
Rockhopper Penguin
Standing a little taller than a foot (42-45 cm) and weighing 3-5 pounds, Northern Rockhopper penguins are mostly black with a white chest and belly, red eyes, and yellow head plumes. They also have large pink feet and grey claws. Younger penguins are less brightly colored. There also Southern rockhopper penguins which in turn has two subspecies, the southern and the eastern.
These penguins are found on several islands in the South Atlantic Ocean and the Indian Ocean, but they are also migratory. On these islands they nest on open boulder beaches in caves and crevices and in high tussock grasses, building their nest out of grass, sticks, feathers and pebbles. The adults arrive at the islands in late July and August, pair up, make their nests, and lay two eggs, of different sizes. Both male and female penguins incubate the eggs for about 34 days, but the first egg is most often lost after a few days. After hatching, the chick is guarded by the male while the female goes off to get food for up to 26 days. Then all the chicks gather in groups called a crèche, while both parents feed them. Once the chicks have moulted, they head off to sea. This occurs about ten weeks after hatching. The adults prepare for moulting by replenishing their body reserves at sea, and by February they return to the islands to moult.
Crustaceans make up 90% of what Rockhopper penguins eat, although they also eat fish and cephalopods.
Image courtesy of Brian Gratwicke
Rockhopper penguins are called that because of how they hop down the rocky slopes of their home island’s shores. Like other penguins, they have a layer of fat, covered in air-trapping fur and waterproof feathers. Unlike other birds, penguin feathers are distributed evenly instead of clustered, making a water and wind proof coat. Their eyes are also specially designed with flattened corneas to be able to see in and out of water. All this and their streamlined bodies help them swim and dive amazingly.
Northern Rockhopper penguins communicate in many ways. They slap each other with flippers, poke with bills, and fight over nesting, mating, and food, braying all the while. They also communicate with penguins they like by bowing, head-shaking, and preening, as well as loud calls to show their location or act as a warning.
Northern Rockhopper penguins are listed as endangered because of rapid decreases in population in the last 30 years, nearly 60%. The main reason for this is climate variation, competition and incidental capture in fisheries. Habitat degradation is also a problem. Recent estimates show that about 240,000 breeding pairs on the islands. Conservation methods have been implemented to stop this. However, not much is known about the reasons or populations because the penguins stay on remote islands.
Works Cited
Northern rockhopper penguin. American Bird Conservancy. (2020, June 24). Retrieved September 18, 2021, from https://abcbirds.org/bird/northern-rockhopper-penguin/.
Northern rockhopper penguins. Australian Government – Department of Agriculture, Water and the Environment: Australian Antarctic Division | Australian Antarctic Program. (2018, March 20). Retrieved September 18, 2021, from https://www.antarctica.gov.au/about-antarctica/animals/penguins/northern-rockhopper-penguins/.
GPS, A. G. B. para. (n.d.). Northern rockhopper penguin - eudyptes moseleyi. Global Penguin Society. Retrieved September 18, 2021, from https://www.globalpenguinsociety.org/portfolio-species-8.html.
Cover image courtesy of Charles Bergman, Shutterstock