Kerguelen shag facts for kids
Quick facts for kids Kerguelen shag |
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| Immature (top), adult (left), and chick | |
| Conservation status | |
| Scientific classification | |
| Genus: |
Leucocarbo
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| Species: |
verrucosus
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| Synonyms | |
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Phalacrocorax verrucosus |
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The Kerguelen shag (Leucocarbo verrucosus) is a type of cormorant. It lives only on the Kerguelen Islands in the southern Indian Ocean. These islands are one of the most isolated places on Earth! Many experts think it is a special kind of imperial shag.
Contents
Where They Live and What They Like
This bird builds its nests on the coast of Grande Terre. This is the main island of the Kerguelen group. They also nest on smaller islands nearby. You can find them on islands inside the Golfe du Morbihan, which is a large bay.
Kerguelen shags look for food in the ocean all around the islands. They usually stay close to shore, about 6 kilometers (3.7 miles) away. They especially like bays and calm inlets. Young birds have been seen much farther out, sometimes as far as 80 kilometers (50 miles). Sometimes, shags seen near Heard Island or western Australia might have traveled there on ships.
In the summer, they often eat among kelp (a type of large seaweed). They sometimes dive to the bottom of the ocean to find food.
What They Look Like
The Kerguelen shag is about 65 centimeters (25.6 inches) long. Its wings can spread out to about 110 centimeters (43.3 inches). This makes it the smallest of the "blue-eyed shags."
Adult birds have shiny greenish-black feathers on their backs, tail, and upper legs. Their chests and bellies are white. The feathers under their wings are brown. Some shags have white patches on their backs and wings. Their heads and the back of their necks are a deep blue or purple. However, a black "cap" covers their eyes, chin, and ears. Their faces and throat pouches are dark brown. They have cool yellow-orange bumps on their faces. Their beaks are horn-colored or brown, and their eyes are hazel. Their legs and feet can be dark brown or bright pink with dark spots.
When they are ready to breed, adult shags look even more special. They grow a small black crest (a tuft of feathers) on their forehead. They also have bright yellow or orange caruncles (which are like large warts) above their beaks. A bright blue ring appears around their eyes. After the breeding season, their feathers become duller. The eye-ring turns a dull blue, and the caruncles get smaller and less colorful.
Young shags are dark brown. They have different amounts of white on their undersides. Their eyes, beaks, and feet are brown. They do not have caruncles, and their eye-rings are a dull blue. They slowly grow their adult feathers.
Unlike many other cormorants, the Kerguelen shag does not spread its wings out when it sits.
What They Eat
Kerguelen shags probably eat mostly fish. They also eat small sea animals without backbones. These include echinoderms (like starfish), crustaceans (like crabs), and polychaete worms. In the summer, they usually hunt alone. But from May to October, they form long lines of hundreds of birds. They dive and come up one after another, moving down the line as they hunt.
Reproduction and Life Cycle
These shags breed in groups called colonies. A colony usually has 3 to 30 pairs of birds. Sometimes, a very large colony can have up to 400 pairs! Their colonies might be close to where southern rockhopper penguins live.
They start building nests and showing off to find mates in late March and early April. This is an unusual time for a cormorant that lives in the cold subantarctic region. Males trying to attract a mate will throw their heads back until their neck touches their tail.
Their nests are shaped like cones. They are made of seaweed, small branches, and grass. The birds hold it all together with mud and guano (bird droppings). Nests can be up to 1 meter (3.3 feet) tall and 33 centimeters (13 inches) wide. The cup part of the nest, where the eggs sit, is about 20 centimeters (7.9 inches) wide and 8 centimeters (3.1 inches) deep. If a nest survives, it might be used again, but maybe not by the same pair of birds.
Breeding can start as early as September. However, the female usually starts laying eggs from late October to late November. This can continue until mid-January. The exact timing can be different for each colony. A female lays two to four eggs. Each egg is about 6.2 centimeters (2.4 inches) long and 3.9 centimeters (1.5 inches) wide. The second egg is laid about 2 or 3 days after the first. Both parents take turns sitting on the eggs for about 29 days.
Both parents also protect their chicks from birds like skuas, gulls, and sheathbills. Even with protection, some chicks are still taken by these predators. When chicks hatch, they are black with a pink throat. They then grow blackish-brown down feathers with grayish-white tufts. We don't know much more about how they raise their young or how many survive.
In the mid-1980s, there were about 6,000 to 7,000 pairs of Kerguelen shags. It seems that people and animals brought to the islands are not harming their population too much.
Classification
Scientists have placed this species in different groups over time. Some put it in the group Halieus, Hypoleucos, Notocarbo, or Leucocarbo. Others place it in the group Phalacrocorax. It has also been thought to be the same species as some other blue-eyed shags, called the imperial shag. However, here it is seen as its own separate species, following what the Handbook of the Birds of the World and other experts say.
Some people have suggested that Heard shags might visit the Kerguelen Islands. They also think that Kerguelen shags with white patches on their wings or backs might be a mix of Kerguelen and Heard shags.
What's in a Name?
The name verrucosus means "full of warts." This refers to the special bumps on the shag's face.
