Birds
Southern Rockhopper Penguin
Eudyptes chrysocome · also called southern rockhopper penguin, rockhopper, rockhopper penguin
The southern rockhopper is the punk of the penguin world — small, red-eyed, with a spray of spiky yellow feathers over each eye — and it climbs the sea cliffs where it nests not by walking but by jumping up them, both feet at once, rock by rock.
Overview
Southern rockhopper penguins breed on subantarctic islands of the southern oceans — the Falklands, southern South America, and islands south of New Zealand and Australia. They are one of the smallest penguins at about 50 cm, and eat krill, small fish, and squid on foraging trips of hundreds of kilometres.
Hopping
Rockhopper colonies sit on steep boulder fields and cliff ledges above the sea. Instead of the usual penguin waddle, the birds spring forward and upward with both feet together, bounding up near-vertical rock to reach the nests, and riding waves in and scrambling clear of the surf against the rocks.
The crest
Rockhoppers are crested penguins. A thin yellow-and-black line runs from the bill back over each red eye and breaks into loose spiky yellow plumes, used in bowing and head-shaking displays and regrown each year.
Insurance eggs
A pair lays two eggs of very unequal size and normally raises just one chick, from the larger second egg — the first egg is a backup.
Status
The southern rockhopper is Vulnerable, down about 30%+ over three generations, with some colonies crashing far harder. The main cause is ocean warming shifting its prey, on top of fishing, oil pollution, and introduced predators.
Southern Rockhopper Penguin: common questions
Why do rockhopper penguins hop instead of walk?
Because of where they live and nest. Rockhopper colonies are typically on steep, broken terrain — boulder fields, cliff ledges, and tussock slopes — sometimes well above the sea, and the birds must cross this ground between the water and the nest many times a day. Rather than the slow, careful waddle that suits the gentler slopes other penguins use, rockhoppers move by springing forward and upward with both feet together, a bounding hop that lets them clear rocks and gaps and climb near-vertical faces surprisingly quickly. They will also hop down the same terrain, and they use their stiff tail and bill to help balance and grip. Getting in and out of the surf against the rocks is done by riding a wave in and then hopping and scrambling clear before the next one.
What are the yellow feathers on a rockhopper's head?
They are ornamental crest plumes, and they mark rockhoppers as one of the "crested penguins," the genus Eudyptes, which also includes the macaroni, erect-crested, Fiordland, and Snares penguins. In the southern rockhopper the crest is a narrow yellow line, bordered black, that starts near the base of the bill, runs back above each bright red eye, and then breaks into a spray of loose, spiky yellow feathers that project sideways and back from the head, giving the bird its punk-rocker look. The plumes are used in courtship and social displays, with birds bowing, shaking, and pointing their heads at each other, and are grown fresh each year after the annual moult.
Why does a rockhopper lay two eggs but usually raise only one chick?
Rockhoppers, like other crested penguins, lay a clutch of two eggs in which the first egg is markedly smaller than the second, and in most years the smaller first egg is lost or its chick dies soon after hatching, so the pair fledges a single chick from the larger egg. The exact reasons are debated, but the pattern is thought to be a form of insurance — laying a second, smaller egg costs relatively little and provides a backup if the main egg fails, while the parents only have the resources to feed one chick to independence in most conditions. In unusually good food years a pair may occasionally raise both.
Why is the rockhopper penguin declining?
The southern rockhopper is listed as Vulnerable after a long-term drop of around a third or more in its global numbers, and several colonies have crashed much harder — the Falklands population fell by well over 80 percent across the 20th century, and Campbell Island south of New Zealand lost most of its rockhoppers between the 1940s and 1980s. The leading explanation is changes in the sea — warming ocean temperatures and shifting currents alter the abundance and distribution of the krill, small fish, and squid the penguins depend on, so adults must travel farther for food and more chicks starve. Additional pressures include competition with and bycatch in fisheries, oil spills, disease, extreme weather events, and predation of eggs and chicks by introduced rats, cats, and pigs on some islands.