Adelie Penguin

Written By: Gabby Guncay, Biology 487, Winter 2009


Pygoscelis adeliae

Status (IUCN v3.1)
Least Concern

The Adelie penguin population is stable and increasing, with some populations increasing by 11.7% near the Ross Sea, Wilkes Land, East Antarctica due to warming trends that increase prey abundance

Conservation Concerns
Adelie penguins are sensitive to human presence via research bases near the Ross Sea, Cape Royds and Terre Adelie. Stricter regulations on construction and disturbances, however, have thwarted population decrease.
A major consequence of global warming is melting of ice selves in the Antarctic Peninsula. When ice shelves disintegrate, land is made available for breeding sites near Palmer land and Graham Land. Higher quantities of available sea ice are advantageous to Adelie Penguins as well.


Adelie Adelie

Population Trend


Descriptive Characteristics
Adult’s heads, upper body and tail are blue-black (fading to brown when worn) with a distinctive ring of white feathers around each eye; under parts pure white separated from black chin and throat by sharp V-shaped demarcation; flipper is blue black dorsally with narrow white trailing edge and small dark area at tip; bill is black with orange-red at base, brown eyes and white/pink legs and feet, soles of feet are black. Juvenile’s immature plumage is recognized by white throats and black eye rings. The plumage is carried for 12 months and molted in February. Chicks have a range of plumage colors, from pale-silver to dark-sooty.

Males are significantly larger than females by bill size and body weight.
Vocalizations: Contact calls are characterized by sharp barking sounds; ‘attack’ vocalizations are an abbreviated growl; sexual calls are ecstatic displays which starts as a rhythmic pumping or clapping sound that climaxes to rasping pulses; and nesting pairs demonstrate quiet humming sounds.

Weight: 5 kg
Height: 73.0 cm
Beak: 4.2 cm
Flipper: 19.6 cm
Foot: 7.5 cm

Weight: 4.4 kg
Height: 70.0 cm
Beak: 3.6 cm
Flipper: 19.3 cm
Foot: 7.3 cm

Breeding Biology


Average Arrival Date: September 20
Average Egg Laying Date: May 10
Incubation Period: 35 days; Full incubation only once second egg is laid. Both male and female incubate egg in alternating shift for a total of 35 days
Average date of first egg is 27 October on Signy Island, 15 November on Cape Royds and 12 Nov on Cape Bird. 50% of clutches were initiated over a 6-day period
Chick Rearing Period: 22 days
Fledging Period: 51 days
Average Annual Reproductive Success: 1 chick/nest
Nest:Nests are lined with small, well-rounded pebbles
Age at First Breeding: 5 years
Maximum Lifespan: 16 years
Egg Weight: 117 grams
Egg Length: 6.9 cm
Egg Breadth: 5.5 cm
Molt: Molting usually begins earlier at higher latitudes according to changes in day length. Molting begins in Cape Royds around February 1 and at Adelie Land around February 10. The molt occurs in yearlings, failed breeders and finally in successful breeders. Juveniles complete their molt in 18.6 days and adults in 19.8 days. The penguins gain about 4 kg to build up fat reserves prior to molt.

E. superba (Antarctic krill) and E. Crystallorophias (Ice krill), Pleuragramma anatarcticum (Antarctic silver fish). Euphausiid crustaceans, E. superba (Antarctic krill) and E. Crystallorophias (Ice krill), make up 70% of diet with additional fish and cephaolopods in the summer (15). Prey size of krill range from 30-45mm. In the winter, penguins are found eating squid, Antarctic krill and lantern fish in order of mass weight quantities.

Leopard Seals prey upon chicks, juveniles and adult adelie penguins on land and at sea. Small chicks and eggs also get predated upon by Skuas.