The largest genus of penguins is Eudyptes, and among the more well known are the rockhoppers. Until recently, there was thought to be a single species of rockhopper (Eudyptes chrysocome) widely distributed in the southern oceans, but populations from certain northern islands were separated; these northern rockhoppers became known as Eudyptes moseleyi. This status is still disputed, however, but I maintain the northern and southern rockhoppers as different species here.
Northern rockhopper penguin
Eudyptes moseleyi Mathews & Iredale, 1921
Adult northern rockhopper penguin (Eudyptes moseleyi)
Distribution: restricted to Tristan da Cunha (South Atlantic), Gough (South Atlantic), Amsterdam Island (South Indian) and St. Paul Island (South Indian).
Size: in the range of 45-58 cm (17½-23”); exact measurements unknown.
Habitat: rugged terrain, talus slopes and tussocks.
Diet: unknown, but probably the same as E. chrysocome.
Etymology: Eudyptes = “good diver” in Greek; moseleyi = named in honour of Henry Nottidge Moseley.
Notes: Recently separated from other rockhopper penguins as a species in its own right – has a longer and more luxuriant crest than Eudyptes chrysocome; it is becoming rare on Tristan da Cunha due to incidental mortality from drift-net fishing.
Southern rockhopper penguin
Eudyptes chrysocome (Forster, 1781)
Adult southern rockhopper penguins (Eudyptes chrysocome); E. c. filholi above and E. c. chrysocome below.
Distribution: circumpolar; breeds on sub-Antarctic and south temperate islands to Heard Island (53oS); winter range unknown.
Size: 45-58 cm (17½-23”); smallest Eudyptes penguin; males up to 4.3 kg (9½lb), females up to 3.6 kg (8 lb).
Habitat: waters of sub-Antarctic north of limit of pack-ice; breeds in rugged terrain, level or gently sloping, talus slopes or steep slopes with tussock; sometimes far from the sea (i.e. on Campbell Island), and up to 60 m above sea level on Marion Island.
Diet: krill, small fish and cephalopods (squid) as well as amphipods and hippolytid crustaceans (shrimp).
Etymology: Eudyptes = as E. moseleyi; chrysocome = “golden hair” in Greek.
Subspecies: E. c. chrysocome = Falkland Islands and islands off Cape Horn; superciliary stripe broad; E. c. filholi = Marion, Crozet, Kerguelen, Heard, Macquarie, Campbell, Auckland and Antipodes; has pink margins to bill.
Notes: Eudyptes chrysocome has been reported to hybridise with the macaroni penguin (E. chrysolophus), erect-crested penguin (E. sclateri) and royal penguin (E. schlegeli).
Southern rockhopper penguin chicks (Eudyptes chrysocome) of different ages