Adélie penguin

Name and taxonomy

Crew on the Antarctic voyage of Jules Dumont d'Urville collected the first specimens around 1840. Two French naval surgeons, Jacques Hombron and Honore Jacquinot, described the bird in 1841. They named it Catarrhactes adeliae, after the stretch of coast the ship had called Adelie Land. That coast carried the name of Adele, the wife of Dumont d'Urville. So the penguin probably honours, at two removes, a Frenchwoman who never saw it.

The species moved through several genera before it settled in Pygoscelis. The genus name joins two Greek words meaning rump and leg. Its members are called brush-tailed penguins, after their long stiff tail feathers. Those feathers sweep the ground as the bird walks and prop it up when it stands. No subspecies are recognised, but two genetic lines exist, one of them in the Ross Sea.

Evolution and relatives

The genus Pygoscelis holds three living species. The chinstrap and gentoo penguins are the other two. DNA work places the split of this line from other penguins about 38 million years ago. That split came about 2 million years later than the branching of the king and emperor line. The Adelie itself appeared about 19 million years ago. The chinstrap and gentoo split from each other some 5 million years later.

An adult Adelie is hard to confuse with anything else. A young bird with a white throat can pass for a chinstrap penguin at a distance. The chinstrap has a black line under the chin and a longer bill with no feathering. On the Adelie the black of the face runs below the eye. All three brush-tailed penguins eat krill and fish, which probably keeps them apart by area rather than by food.

Appearance

The Adelie is a middle-sized penguin, 70 to 73 cm long. Weight ranges from 3.8 to 8.2 kg across the year, and a bird is heaviest before it fasts. Animal Diversity Web gives a narrower band of 3.62 to 4.99 kg. The sexes look alike, though the female has shorter wings and a shorter bill. She also weighs noticeably less than her mate.

The back, head and throat are black and the belly is clean white. Black feathers cover most of the bill and leave only the tip bare. The bare tip is black, sometimes with faint reddish brown marks. The top of the flipper is black, edged white behind, and the underside is white with a thin black front line. The legs and feet are pink and mostly bare of feathers.

A newly hatched chick wears silvery grey down, darker on the head. Within about ten days it moults into a coat of smoky grey down. A third moult, 7 to 9 weeks after hatching, gives it the adult pattern. A young bird is smaller, bluer above, and has a white chin instead of a black one. It does not gain the full white eye ring until it is at least a year old.

Habitat and range

Only four penguins nest on the Antarctic continent, and this is one of them. Colonies ring the coast and reach the South Orkneys, South Shetlands and South Georgia. Birds are much scarcer north of 60 degrees south. Strays have reached Australia, New Zealand and southern South America. The British Antarctic Survey counts it among the few penguins that belong to the continent itself.

A breeding colony needs bare rocky ground that stays clear of drifting snow. Birds pick slopes where the wind or the angle of the sun keeps the drifts away. At the start of the season the colony may sit up to 100 km from open water. That distance shrinks through the summer as the pack ice breaks up. After breeding, most adults move onto floes or ice shelves to moult.

Winter is spent in the pack ice rather than on land. Most birds move north of about 73 degrees south, where some daylight still reaches them. They can live far south of open water as long as the ice keeps cracking open. Birds have been found feeding in winter where pack ice covers 80 per cent of the sea. In January 2026 a single Adelie turned up at a research station 200 km inland.

Diet and feeding

Antarctic krill is the main food, and ice krill and sea krill are taken too. Antarctic silverfish and lanternfish make up most of the fish in the diet. Amphipods, glacial squid and other cephalopods fill out the list. The mix changes from one part of the coast to another. Jellyfish were once thought to be swallowed by accident, and birds are now known to seek them out.

A breeding adult swims 5 to 120 km out from the colony to feed. It works the top 70 metres of the water column and can dive to 175 m. It brings back 300 to 650 grams of food for the chicks in one trip. Food is stored in the stomach and brought up part-digested at the nest. Birds hunt in groups, which finds food faster and keeps seals at bay.

Eggshell fragments in the colonies record 38000 years of diet. They show a sharp switch from fish to krill that began about 200 years ago. Sealers cut down the Antarctic fur seal from the late eighteenth century. Whalers then removed most of the baleen whales in the early twentieth century. Both groups ate krill, so their loss probably left a surplus the penguins now take.

Behaviour and social life

The Adelie is a social bird and spends its life among others of its kind. Groups travel together from the pack ice to the nesting beach each spring. Outside the nest site the birds hold no territory at all. A pair defends only the small patch of stones it has built. Neighbours fight often, and a bird will peck and yell to keep its ground.

On land the bird walks upright with a rolling gait. It can also hop forward on both feet or toboggan on its belly across snow. In the water it usually swims at about 8 kilometres per hour. It porpoises, breaking the surface in a low arc to breathe without slowing. It can leap about 3 metres clear of the water onto a rock or an ice edge.

Early explorers wrote a great deal about the bird's nerve. Apsley Cherry-Garrard compared the penguins to self-important children in his book on Scott's expedition. Members of Scott's party watched penguins walk straight up to a team of sled dogs. A film crew in 2018 recorded one Adelie driving a giant petrel away from emperor penguin chicks. The bird will challenge animals far larger than itself.

Communication and senses

Display and posture carry most of the messages in a crowded colony. A male advertises with a salute, standing at his full height and thrusting his bill upward. He performs it about 4 metres from a female, and it also announces his patch of ground. A raised crest of head feathers signals unease. A sideways stare with the crest up and the eyes rolled down is a threat.

Calls carry identity as well as mood. A pair knows each other's voice, and each parent knows the call of its own chick. That skill probably matters most in a crowd of thousands, where sight alone would fail. Returning birds recognise both their mate and last year's nest site. Mates use a louder, more excited display that only the two of them use together.

Reproduction and life cycle

The season runs from October to February. Males arrive first and rebuild a nest of stones on last year's site. Before laying, both birds feed hard to lay down the fat they will need. The female lays two eggs, the second shortly after the first. Pairs often reunite year after year, unless one bird fails to return.

The two parents take turns to incubate, in shifts of about 12 days. The sitting bird eats nothing and does not even leave to pass waste. It fires its droppings clear of the nest instead. Incubation takes 32 to 34 days, and Animal Diversity Web gives about 36 days. The chicks hatch downy and helpless and cannot feed themselves.

Both parents feed the brood for about 22 days at the nest. The chicks then gather in a creche, which lets both adults go to sea. The parents keep feeding their own chick inside the creche. Chicks moult into their first proper plumage and go to sea after 50 to 60 days. Females first breed at 3 to 6 years old and males at 4 to 6. Birds that start young breed less successfully at first and better in later years.

Predators and threats

Leopard seals take adults, mostly at the edge of the pack ice. Penguins reduce the risk by swimming in groups and by leaving the water quickly near a beach. Orcas and giant petrels kill adults now and then. South polar skuas take eggs and unguarded chicks, and so do kelp gulls and sheathbills. A leopard seal is no danger ashore, since it comes on land only to rest.

Sea ice is the larger problem. The bird lives on the ice but must have bare land to breed, so both matter. Numbers on the Antarctic Peninsula fell by 65 per cent over 25 years as the ice thinned. Bird flu is a new arrival, having reached South America in 2022. Researchers found more than 532 dead Adelies on Heroina Island in 2024, with H5N1 suspected.

Population and conservation

The IUCN lists the Adelie penguin as Least Concern. The 2020 assessment put the total above 10 million mature birds. The habitat is continuous rather than broken into fragments, which helps. A census in 2014 combined satellite images with field counts. Guano stains the rock, so a colony shows up as a red-brown patch from orbit.

That census found 3.79 million breeding pairs in 251 colonies. More than 40 of those colonies had never been counted before. The total was 53 per cent higher than a count made 20 years earlier. Peninsula colonies have shrunk since the early 1980s, and East Antarctic ones have grown more. A colony of 1.5 million birds was found in 2018.

The Danger Islands hold 751527 pairs in at least five colonies. BirdLife International names the group an important bird area for that reason. The Windmill Islands colony grew from 30000 pairs in the 1950s to close to 200000. Single colonies swing widely, so a global figure probably hides a lot of local change. The species is protected across the Antarctic Treaty area.

Relationship with humans

Sealers and explorers used the birds from the eighteenth century to the early twentieth. They took them for food, for oil and for bait. Their guano was dug out and sold as fertiliser. The species is now protected in most countries. Colonies are a main draw for Antarctic tourism.

The bird has no harmful effect on people at all. Scientists watch it as a measure of a warming continent. Penguins now nest on beaches that used to stay under ice all year. George Murray Levick studied the largest colony at Cape Adare over one full season. His notes on their sexual behaviour were held back as indecent and published only in 2012.

In culture and myth

The Antarctic has no native human population, so the Adelie probably carries no old folklore. Its place in culture appears to come instead from the age of polar exploration. In British polar tradition, Apsley Cherry-Garrard wrote of the bird's gallant pluck against long odds. In the same tradition, Levick described birds pushing one of their number into the water first. In French naming tradition, the species carries the name of Adele Dumont d'Urville.

Cherry-Garrard called the penguins little people of the Antarctic world. Scott's diary complained that their curiosity walked them straight into the dog teams. Those accounts probably fixed the penguin in English writing as comic and brave at once. The 2018 BBC series Spy in the Snow showed one bird defending another species' chicks. That clip spread widely and probably gave the species a new reputation for nerve.