Royal penguins

Royal penguin
Royal penguin (Photo: Dave Bone)
Massed royal penguinsSeveral royal penguins at Sandy BayRoyal penguins heading up Nuggets CreekTwo royal penguins stand rather close to each other and look to the left of the photoRoyal penguin with a rock in its beakMoulting royal penguin chick. It has tufts of down feathers though the crown of yellow feathers is starting to showA large elephant seal lies in the middle of a herd of royal penguins, one of which is standing on its back as it looks nonplussedRoyal penguin asleep on the ground

Scientific name: Eudyptes schlegeli

Name derivation

Royal penguins are one of the crested penguins (genus Eudyptes), named for the yellow plumes on their heads; the species name commemorates the German zoologist Hermann Schlegel. Eudyptes means ‘good diver’ and is derived from the Greek word eús (good) and dýtis (diver).

Physical description and related species

Royal penguins are mid-sized penguins but they rank amongst the larger crested ones. In many ways they look similar to macaroni penguins but royals are up to 20% larger than macaronies and also have tend to have white to pale grey faces while macaronies have black faces. The yellow plumes on their heads meet on the forehead. It takes several years for the crests to develop fully. Thus, in young penguins the crests are not as lush as in adults. The sexes are similar but males tend to be somewhat larger than females.

At the start of the breeding season, royals weigh 4.2–6.3 kg. During the breeding season they tend to lose weight; at the end of the guard period the penguins weigh only 3–5 kg. In preparation for the annual moult they have to fatten up and lay down body reserves; their body mass thus increases to up to 8 kg.

Distribution and abundance

Royal penguins are endemic to Macquarie Island where the vast majority lives, and the nearby Bishop and Clerk Islets where about 1000 pairs breed. Royals at Macquarie Island live in very large colonies. The largest colony at Hurd Point on Macquarie Island has around 500 000 pairs. Precisely how many royal penguins there are is unknown but the population is thought to be currently stable.

During the breeding season, royals forage in areas southeast of Macquarie Island where the waters are 4000–5000 m deep. They tend to spend time at the northern edge of the Polar Frontal Zone but the distances they travel and the areas they visit vary throughout the breeding cycle. Partners of incubating birds travel over 600 km from Macquarie Island and back again in three weeks. After the moult, royals leave the island; it is still unknown where they go during this time, although there have been sightings from Tasmania to the Antarctic sector of the Southern Ocean.

Conservation status: vulnerable

For many years, they were killed and boiled down for oil.

Breeding

The breeding cycle of royal penguins is highly synchronised cycle and starts when the males arrive in late-September to claim nest sites. The females arrive in early October and lay their eggs in mid- to late-October. Incubation lasts about 30 days and chicks start to hatch in early late November/early December. The chick rearing period extends over two months. Males guard the chicks for three to four weeks, until the chicks are large enough to join crêches (kindergartens). From mid-January onward both parents are free to feed the chick and each adult foraging cycle lasts about two days. In late February the chicks start to fledge and get ready to go to sea. The adults moult in March/April and then leave the island for about six months over winter.

Diet and feeding

Royal penguins hunt mainly for two species of krill: Euphausia valentini (~ 40% by weight) and some Thysanoessa gregatia (~10% by weight).The rest of their diet is made up by juvenile lantern fish (myctophids). The proportions change throughout the breeding cycle. The diet differs at colonies around the island, particularly between the east and west coasts and shows substantial annual differences.