Rockhopper penguins do just what their name says. In the steep, rocky places where these birds live, hopping from rock to rock is the only way to get around. Boing! Boing!
Rockhoppers grow about 46 cm tall—almost as high as an adult’s knee. They are the smallest of the crested penguins. Crested penguins are a group of penguins with extra-long head feathers that look like fancy hairdos. Rockhoppers are found on islands near Antarctica. They are carnivores that eat sea animals such as fishes,krill, and squid.
Rockhopper penguins are specialists at hopping long distances up the face of cliffs—sometimes 30 meters (100 ft). In the safety of these high cliffs they build their nests and raise their chicks.©M.Campbell/GLOBIO.org
Rockhoppers are most at home in the water. They swim with their powerful wings or flippers and use their tails and feet to guide them. When traveling extremely fast they loop in and out of the water—called porpoising. In one mighty burst, they leap high on the rocks and land on the shore—often crashing on their bellies before quickly waddling to safety.©J.Ferrero/Minden Pictures
Rockhoppers are great swimmers. Like all penguins, rockhoppers cannot fly. But when they swim, they look like they are flying underwater! They flap their stiff, powerful wings, called flippers, as they swim along. The flippers work like paddles. They help the penguins steer, along with their feet and tail.
Sometimes rockhoppers will leap in and out of the water as they swim. This is called porpoising. It’s a great way for them to take breaths without having to slow down. It also may help keep them safe by confusing predators. When a rockhopper is finished swimming and ready to come ashore, it becomes a hopper again. It makes a giant leap out of the water onto the rocks.
Built for the Brrrrr
Rockhoppers have some great adaptations for staying warm in their cold home, whether they’re on the windy shore or in the chilly ocean. First, they have a thick layer of fat under their skin, which acts like a blanket to keep out the cold. Close to their skin they have a layer ofdown that helps hold in heat. And on top of that, they have very special waterproof feathers. The feathers overlap tightly like scales to keep out water and wind. Penguins have more feathers than any other kind of bird—up to 12 per square centimeter!
Scientists believe that rockhoppers and other penguins evolved from flying birds that were like the albatrosses of today. About 80 million years ago, these birds began changing from birds that fly to birds that swim. Their wings became smaller and flipper-shaped. Their feathers became waterproof. Their bones became heavier and more solid to aid in swimming and diving. All these changes took millions of years to happen. There were about 40 species of early penguins. One kind grew to be about 1.5 m tall—the height of some people!
Rockhoppers calling or “braying” is a very noisy activity. In a large colony of penguins the sound can be extremely loud! The brays signal to the birds and their chicks where they are located within the colony of hundreds, maybe thousands of penguins constantly traveling between the sea and their nests.©M.Campbell/GLOBIO.org
If you visit a place where rockhoppers live, you’d be amazed at how noisy it is. Penguins “talk” to each other a lot, with noises called ecstatic vocalizations. They do this to call for a mate, to let other penguins know where their territory is, or just to announce their presence. Male and female mates often call to each other and to their chicks. Chicks call to their parents.
Penguins also talk with their bodies by using different motions. For example, a mated pair of penguins may shake their heads, flap their wings, or bow at each other. They defend their nesting territories with pecks and flipper slaps. The motions and calls are just the penguins’ way of expressing their feelings!
All in the Family
Rockhoppers return to the same breeding site each year and even use the same nest when possible.©M.Campbell/GLOBIO.org
Rockhoppers spend the winter months of the year at sea. They swim, find food, even sleep on the waves. But when it’s time to mate, huge groups of rockhoppers come ashore. These groups, calledcolonies, can have hundreds of thousands of penguins! Males arrive first. The females come a few weeks later. The males call to attract their mate from previous years. Rockhoppers usually mate for life and use the same nest each year. The nests are built among the rocks. They are made of pebbles, sticks, feathers, or plant parts. The female rockhopper lays two eggs, though often only one hatches. The parents take turns sitting on the eggs. While one waits, the other spends days feeding at sea. When that one returns, they switch. In a little over a month, a chick hatches.
Ball of Fuzz
The male and female guard the eggs and keep them warm for 32 to 34 days. They take turns, each taking care of the eggs for 10 days at a time. When the chick is hatched, the male broods and cares for the chick while the female fishes and brings home food.© M.Campbell/GLOBIO.org
A newly hatched rockhopper chick is covered with fuzzy black-and-white down. It’s about the size of a plum. (Rockhoppers don’t get their showy yellow crests until they are adults.) A chick’s parents take turns feeding it by regurgitating, or throwing up, food they have swallowed. Eating warm, fishy glop might not sound too delicious to you, but penguin chicks love it!
When the chicks are about 25 days old, it’s time for them to join other chicks in a group called a crèche. This allows both their parents to leave and hunt for food. The bigger the chicks get, the more food they need. When a parent returns to the crèche with food, it calls its chick to come. Chicks can tell their own parents’ calls from the calls of other adult penguins. The parents keep taking care of the chicks until they are about 10 weeks old.
When rockhoppers preen each other it strengthens the bond between the mates. Preening activity is also very noisy with each bird taking its turn to “bray” very loudly as it tosses its head back.©K.Campbell/GLOBIO.org
Bad Feather Days
Each year, rockhoppers go through a process called molting, when they shed their feathers. It’s important that a penguin’s feathers be in tip-top condition to stay waterproof and keep the penguin warm. But after a penguin has spent a year climbing on rocks, rubbing against other penguins, and preening for hours a day, its feathers become worn and ragged. That’s when it’s time to grow new ones. New feathers grow in under the old ones, pushing them out. A molting penguin can look pretty scruffy and messy. During molting, feathers lose some of their waterproofing. Molting penguins stay out of the water until all their sleek new feathers have grown in.
Rough, Tough Customers
Rockhoppers are known for being rather cranky and pushy! Nesting neighbors constantly squawk and peck at each other as they protect their territory. Sometimes actual fights take place. Penguins hit each other with their flippers, peck each other, or lock beaks. Even parents coming back from the sea to feed their chicks are met with numerous pecks and warning squawks as they pass other penguins that are protecting their nests.
Danger in the Sea
Most penguin chicks are safe in their high, cliff nests. Their parents aggressively protect them from predators such as skuas and caracaras. The chicks’ first trip down the cliffs can be dangerous from accidentals falls and hungry predators.©K.Campbell/GLOBIO.org
Unfortunately, rockhoppers aren’t tough enough to protect themselves from their enemies when they are in the water. Rockhoppers are prey for leopard seals, fur seals, sea lions, and blue sharks. The rockhoppers’ coloration gives them some protection. Their black backs blend into the dark water when viewed from above and their light bellies blend into the brighter surface water when seen from below. On land, petrels and gull-like birds called skuas prey on rockhopper eggs and chicks.
There are about 7,340,000 rockhopper penguins in the world. That may seem like a lot, but the population of rockhoppers has actually decreased by 30 percent over the last 30 years. If the rockhopper population keeps falling, they may soon be considered anendangered species. One of the biggest problems rockhoppers and other penguins face is overfishing, which results in a shortage of prey. Another threat is water pollution, including oil spills.
Rockhoppers can dive up to 100 m (328 ft) in depth. When the penguins go on their feeding trips at sea they sometimes get caught in commercial fishing nets.©G.Ellis/GLOBIO.org
Yet another danger may be climate change. As water temperatures rise due to global warming, less prey may be available for rockhoppers and other penguins. Scientists still don’t know all the causes of the decline in the rockhopper population. But they are studying the effects of climate change and also working with conservationiststo find ways to prevent overfishing and pollution. Some zoos and aquariums have begun successful captive breeding programs to increase the number of rockhoppers and other penguins.
People love penguins. Maybe it’s the cute way they waddle when they walk or the way they stand upright like we do. Sometimes penguins seem more like comical little persons in tuxedos than like animals. In recent years penguins have become more popular than ever. They have been featured in movies and nature shows and each year, people meet real penguins at zoos and aquariums. Some even travel to areas where penguins live in order to watch them in their natural surroundings. The fascination and fondness people have for these loveable birds will hopefully go a long way toward saving them.