Eastern rockhopper penguin

Description

The eastern rockhopper penguin has a black back and throat, a white belly, and pink feet. It measures 45–55 cm in length and weighs 2.2–4.3 kg. A thin yellow stripe runs from its lower forehead over its red eye and splits into crest feathers at the back of its head. The crest consists of long, thin, spiky yellow feathers on each side, joined by shorter black feathers.

Its bill is orange-brown with distinctive pink margins. Males are generally larger and have a thicker bill than females. Fledglings are bluish black all over without crest feathers. Juveniles are black-brown with a grey throat and small yellow crest feathers; adult plumage is attained at 2 years old.

Distribution and habitat

The eastern rockhopper penguin is found in the southern Indian and Pacific oceans from Prince Edward Islands to the Antipodes Islands. It breeds on Marion Islands, Macquarie Island, and subantarctic islands in New Zealand such as the Antipodes Islands and Campbell Island. It occupies a mainly marine pelagic habitat, returning to land only to breed and moult. During winter (April to October), it forages in the southern Indian Ocean, traveling 2000–4000 km from its breeding site and spending up to 6 months at sea.

It forages in cool waters below 4.5°C. It is a surface nester, building nests of small pebbles on slopes or rocky shores near the coastline, often in colonies of tens of thousands. Some colonies settle in grasslands, but soil erodes to rock over decades due to guano and trampling. It is rarely found more than 200 metres from the coast.

Behaviour

Eastern rockhopper penguins use calls for parent-chick recognition when returning with food. Their courtship song is a short, repeated, rhythmic ascending song with 5–30 syllables, the first being the longest. The contact call of chicks and adults is a very short, shrill bark.

Their diet includes fish, crustaceans, and cephalopods such as krill and squid, varying by life stage and location. During pre-moult, they mainly consume crustaceans; during breeding at Marion Islands, they rely heavily on euphausiids. Chicks at Campbell Islands were found to eat dwarf cod.

They depend on predictable food sources near the nest but can forage up to 120 km away if needed. They forage in cool, productive waters and select areas with eddy currents that support high prey aggregations. Predators include fur seals, sea lions, brown skuas, and northern giant petrels.

Threats and Conservation

The eastern rockhopper penguin is considered vulnerable due to rapid population declines, most evident in breeding regions. The decline is attributed to low food availability and reduced food quality driven by climate change. Changing sea surface and ocean temperatures affect prey distribution, forcing adults to forage farther from colonies and return with less food for chicks, reducing chick body mass.

Low food availability also increases mortality during the energy-demanding moulting period. Poor food quality and abundance in wintering regions raise adult mortality. Climate change has also increased storm intensity in breeding ranges, displacing prey and reducing foraging success.

Did You Know?

• The species was formally described in 1879 by Frederick Wollaston Hutton based on a specimen from Campbell Island.
• The specific epithet filholi honors French medical doctor and palaeontologist Henri Filhol.
• A molecular phylogenetic study published in 2021 led to its recognition as a separate species from the western rockhopper penguin.