Chinstrap penguin

Chinstrap penguins mostly eat krill.

Krill are tiny animals that look like shrimp. The penguins also eat small fish. They catch them close to their island.

Chinstrap penguins feed mainly on Antarctic krill, small shrimp-like animals, and on fish. They are near-shore feeders, hunting close to their breeding colonies.

They catch prey by chasing it underwater, using their flippers to "fly" through the sea. They usually feed less than 40 meters deep. They hunt both day and night, but dive most around midnight and around noon, and they dive deeper in daylight than in the dark.

The diet is dominated by Antarctic krill, with fish also taken. Chinstraps are near-shore foragers that pursuit-dive close to their colonies, using their flippers for underwater propulsion. Most dives are shallower than 40 meters, and although they forage around the clock, diving effort peaks near midnight and noon, with deeper dives by day.

Because they depend so heavily on krill, chinstraps are sensitive to changes in its abundance: the Australian Antarctic Division reports recent evidence suggesting that numbers are declining significantly because of reductions in krill. The IUCN notes that Pygoscelis penguins are major consumers of Antarctic krill and carry marine nutrients onto land in their guano.

Chinstrap penguins live together in giant groups.

One island has more than a million pairs! Skuas and seals are dangers for them.

Chinstrap penguins nest in enormous colonies. National Geographic reports that the largest, on Zavodovski Island in the South Sandwich Islands, has about 1.2 million breeding pairs, and Baily Head in the South Shetland Islands has more than 100,000 pairs.

At sea, the main predator is the leopard seal. On land, skuas, sheathbills and giant petrels take eggs and chicks. Volcanoes can be a danger too: in 2016 an eruption on Zavodovski Island covered much of the colony in ash.

Colonies can be immense: National Geographic cites about 1.2 million breeding pairs on Zavodovski Island in the South Sandwich Islands and more than 100,000 pairs at Baily Head in the South Shetlands. The IUCN notes that colonial penguins are more vulnerable to predators in very small colonies, so large colonies offer some self-protection.

Leopard seals are the main predator at sea, while sheathbills, skuas and southern giant petrels take eggs and chicks on land. Zavodovski Island is volcanic, and a 2016 eruption covered much of the colony in ash while the birds were molting, when they cannot go to sea because their feathers are not waterproof.

There are still millions of chinstrap penguins.

But there are fewer than before. They need lots of krill to eat. Rules stop visitors from getting too close to their nests.

The chinstrap penguin is listed as Least Concern, and there are still about 8 million adults. But the IUCN says the population is going down, and scientists think that less krill to eat is a big reason.

Almost all chinstrap colonies are protected under the Antarctic Treaty. Tourists who visit Antarctica must keep a safe distance from breeding birds, and countries work together to manage krill fishing in the Southern Ocean.

The IUCN's 2020 global assessment lists Pygoscelis antarcticus as Least Concern, with about 8,000,000 mature individuals and a decreasing trend; its Green Status assessment rates the species as Moderately Depleted. Listed threats are fishing and harvesting of marine resources, volcanic activity and climate-driven habitat shifting.

National Geographic notes that numbers rose in the mid-twentieth century, which some attribute to a rebound in krill after centuries of seal and whale hunting, and that some populations are now declining, though not precipitously. Almost all colonies lie within the Antarctic Treaty area, and restrictions keep tourists from approaching breeding birds too closely.