Population: more than 300,000 pairs
Conservation Status: Near Threatened (IUCN, 2009)
Length: 75-90 cm
Weight: 4.5 to 8.5 kg
Mating/Breeding: Gentoo penguins are ground nesting birds, making rudimentary nests from stones, sticks, grass, feathers, or practically any material that they can find suitable for the purpose. Egg-laying is usually completed by late October, with two equally sized eggs of about 130g being laid. Incubation takes about 34 days, with both parents sharing incubation duties, and nest changes occurring every 1 to 3 days. Despite the two eggs being laid 4 days apart from each other, they both hatch within the space of 24 hours.
The young chicks remain in the nest until they grow their mesoptile plumage at about 3 to 4 weeks of age. During this period both parents brood the chicks alternately, feeding the chicks and changing over on a daily basis. Adults usually set out to forage in the early morning, returning later the same day, and foraging generally occurs within 20km of the breeding site. The time spent foraging increases as chicks get larger, and their demand for food gets greater.
After the brood period, chicks are able to leave the nest and form into large crèches, allowing both parents to collect food to meet the ever increasing demand.
Feed on: Chinstrap Penguins feed almost exclusively on krill. Other crustaceans and fish play a minor role.
Threats: Gentoo penguin eggs are taken by skuas. Young birds are preyed upon by sheathbills, caracaras (falcons), kelp gulls, giant-petrels and feral cats, while older birds are taken by leopard seals. Nests are often flattened by indifferent elephant seals as they move about the island. While some Antarctic populations, which total 25% of overall numbers, have doubled within the last two decades, most sub-Antarctic colonies are in decline, possibly as a result of over-fishing of penguin prey species.
Colour/Looks: Gentoo Penguins are characterised by a white patch around and behind the eye that joins on the crown. The orange-red lower mandible is also a distinct feature. Two subspecies are recognised: a larger form in the sub-Antarctic and a smaller, but otherwise similar subspecies on the Antarctic Peninsula.
Juveniles are very similar to adults, but the white eye-patch is not connected to their white eye-rings until they moult at an age of 14 months.
Where found: Gentoo penguins breed on sub-Antarctic islands and on the Antarctic Peninsula in small to large colonies. Larger populations of gentoo penguins are found at South Georgia, the Falkland Islands and the Iles Kerguelen.
- Young gentoo penguins are very adventurous and have been spotted on the coasts of New Zealand and Africa.
- During deep dives, gentoo penguins reduce their heart rate from 80-100 beats per minute (bpm) down to 20 bpm.
- The gentoo penguin was first described by Sonnerat in 1776, who spoke of Manchot papou. The gentoo penguin got its scientific name (papua) while they thought by mistake to have seen this species in Papua/New Guinea. Forster used in 1781 the scientific name “Aptenodytes papua”, and the subsequent name “Pygoscelis papua” derives from Wagler in 1832. Gentoo seems to be an archaic word for Hindu, the white marks on the bird’s head apparently reminding early voyagers of a turban. Sealing crews referred to it as Johnny penguin.
Hadoram Shirihai, A complete guide to Antarctic wildlife (2002)
David McGonigal & Lynn Woodworth, Antarctica and the Arctic. The complete encyclopedia (2001)