Description & Characteristics:
The Gentoo (jen-TOO) penguin has the widest range of distribution of any penguin. However, the most significant populations are concentrated on the Antarctic Peninsula and sub-antarctic islands. Large breeding colonies of Gentoos are found on South Georgia, the Falkland Islands and the Kerguelen Isles. Members of the brush-tailed genus (Pygoscelis) which includes the Adelies and the Chinstraps, Gentoo populations have suffered over the last century from human depredation and loss of habitat but appear to be stabilizing recently due to increased conservation efforts.
Gentoos are distinguished from the smaller Adelie and Chinstrap species by their bright red-orange bills and conspicuous white patches behind their eyes. Long stiff tail feathers stick out behind them as they walk. When swimming, these prominent tails are often cocked up in the water, making them fairly easy to spot.
Gentoos feed on Rock cod, Lantern fish, crustaceans (krill), amphipods and cephalopods (mainly squid). They typically forage at sea close to the colony, and thus their chicks are fed frequently. Females tend to eat more krill than the males, while the males tend to eat more fish. Gentoo penguins are gregarious at sea, meaning they will form ‘rafts’ of hundreds of individuals to aid in catching prey. Most prey is caught on shallow pursuit dives lasting only half a minute, although they can dive to at least 330 feet.
Roughly circular in shape, Gentoo nests are found on rocky, uninhabited shores; built out of whatever supplies are at hand, though they seem to prefer grass and vegetation. Competition for nesting materials can be fierce as they will aggressively fight over stones or take stones and other material away from other birds’ nests. In September or October, Gentoos generally lay two eggs three days apart from each other. The second egg is often smaller than the first. Both eggs are then guarded zealously by the parents until they hatch about 5 weeks later. Chick survival is often dependent on the availability of food and the lack of predators. If food is in short supply the parents will preferentially feed the stronger of the two chicks sacrificing the weaker one. The chicks stay in the nest for about a month at which time they form nursery groups or ‘creches’, while their parents hunt for food. After about 3 months (usually in January) the chicks grow their adult feathers and are able to head out on their own.
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 colonies.