Southern rockhopper penguins
Scientific name: Eudyptes chrysocome
Physical description and related species
Southern rockhopper penguins are the smallest of the crested penguins weighing only 2–3.8 kg. They are thus only bigger than little penguins (Eudyptula minor).
Distribution and abundance
Southern rockhopper penguins have a circumpolar distribution, and are found on islands in the region of 46–54°S. The islands they occupy include Heard Island and the McDonald Islands, as well as Macquarie Island.
Over the past few decades, populations have significantly decreased. Most seriously affected were the colonies at the Falkland Islands (Malvinas). Although researchers are unsure what threats are predominantly driving current population declines, it appears that climate changes is playing a significant factor.
Conservation status: vulnerable
The start of the breeding season depends upon where southern rockhopper penguins live and can vary by as much as six weeks. There are also annual variations within the same colony. The females usually lay two eggs within 4–5 days of each other in November. Initially, both partners remain at the nest for a few days. After this, the males depart and go to sea returning two to four weeks later. Like other crested penguins, their first egg is smaller than the second one. Both eggs may survive and hatch.
The eggs are incubated for 32–34 days. Once the chicks hatch, the male guards them for about 3 weeks while the female feeds the offspring. Chicks are usually ready to leave the colony in mid-February (depending on when the breeding season started).
Adult penguins have to prepare for their annual moult. If food is plentiful, they moult early. If food is difficult to find, the penguins delay their moult. Generally, the last birds finish in mid-May.
Diet and feeding
Southern rockhopper penguins hunt a variety of prey, but crustaceans and cephalopods appear particularly important. Generally, diet composition varies with location and season. On average, southern rockhoppers dive to 20 or 30 metres but a maximal dive depth of 113 metres was recorded in one study.