Saturday 8 November 2008

Northern & Southern Rockhopper Penguins

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


Glendon Mellow said...

I've always thought of rockhoppers as one of the most unlikely looking animals.

The yellow head feathers seem like the type of glitz added by a motorcycle airbrush artist, or the type of embellishment a cartoon show would add to distinguish a quirky character.

m said...

Yep, they certainly do look like that!