Rockhopper penguin  (Eudyptes chrysocome)

The rockhopper penguin is one of the smallest of the penguin species. The characteristically robust body is white on the underside and slate-grey above, with a yellow line above the eye that extends into yellowish plumes (3). Behind the head there is also a crest of black feathers, the short bill is reddish brown in colour and the eyes are red (2). Juveniles can be identified by the lack of adult yellow markings (2).

Rockhopper penguins breed on a number of Southern Ocean islands. Three subspecies are recognised, the southern rockhopper (Eudyptes chrysocome chrysocome) is found in the Falkland Islands, Isla Pinguino, Staten Island and islands off southern Chile and Argentina (3). The northern rockhopper (E. c. moseleyi) breeds on Tristan da Cunha, Amsterdam and St Paul Islands (3). Whilst the eastern rockhopper (E. c. fiholi) is found on a variety of islands ranging from below the coast of South Africa to that of New Zealand (3).

Nesting occurs on cliffs and rocky gullies, usually situated near to freshwater, either natural springs or puddles (2).

Penguins are gregarious, and rockhopper penguins breed in large colonies that may be composed of over a hundred thousand nests (2). They are monogamous, and pairs usually return to the same nest on consecutive years (2). Eggs are laid in November, clutch size is generally 2 eggs of unequal size, with only the chick from the larger egg usually surviving to maturity. Incubation takes around 33 days and both parents will take it in turns to sit on the eggs for extended periods of a time whilst their partner forages for food; penguins have a bare patch of skin on the lower abdomen (known as a 'brood pouch') that allows greater heat transfer to the eggs (2). Once the chicks have hatched the male will remain to brood them for the first 25 days, whilst the female regularly brings food back to the nest (2). After this time, the chicks are able to leave the nest and are left in small groups known as 'crèches' whilst their parents forage (2).

Penguins have a waterproof coat that is maintained by constant grooming; this helps to flatten the feathers and to spread a waxy substance that is secreted just below the tail. Grooming is also an important social bond between pairs (2). Once a year however, the coat must be replaced; this annual moult takes around 25 days and occurs roughly a month after the completion of breeding. Prior to this imposed fasting period, adults spend time at sea building up fat reserves (2). After moulting, the winter months are spent at sea before returning to shore to breed the following spring. The diet of the rockhopper penguin is composed of a variety of oceanic species such as crustaceans, squid, octopus and fish (3). Groups may often feed together and dives may be to depths of up to 100 metres (2).

Some rockhopper nesting colonies have recently shown dramatic falls in population numbers; the Falkland Islands once housed the stronghold for southern rockhopper penguins, but over the last 20 years, numbers have declined by 90% (3). The reasons for these declines range from increasing disturbance and pollution, to declining fish stocks as a result of over fishing, failure to provide no-fishing zones around penguin colonies (4) and global warming (3). In some areas, such as Nightingale Island, the collection of eggs continues to affect the population whilst around Tristan da Cunha, driftnet fishing practices have caused significant mortality in the population of rockhopper penguins (3).

Many islands that house breeding colonies have been designated as reserves and the populations in the Falklands, Tristan da Cunha, Marion, Amsterdam, St Paul and Campbell Islands are regularly monitored and studied (3). Greater investigation of population demographics and of potential threats is required. Following the starvation of over 100,000 rockhopper penguins in the Falkland Islands, the Spheniscus Penguin Conservation Work Group published a report recommending that commercial fishing be excluded within 30 miles of penguin breeding sites (2). These measures have been adopted around southern Chile and Argentina, and these sites are healthy and increasing as a result. The adjacent Falklands have refused to introduce such protection, and populations continue to decline (4).

For more on the rockhopper penguin see:

• BirdLife International's World Bird Database
  http://www.birdlife.org/datazone/search/species_search.html
• International Penguin Conservation
  http://www.penguins.cl
• Falklands Conservation
  www.falklandsconservation.com
• Organisation for the Conservation of Penguins. English:
  http://www.seabirds.org
  Spanish:
  http://seabirds.org/chile.htm

Information authenticated by Mike Bingham of the Organisation for the Conservation of Penguins:
http://www.seabirds.org