Tern

Terns are birds that live near water.

They have long tails and thin wings. They can run well on the ground. Most have grey backs and white bellies.

They also have a black cap on their heads. Some terns have dark feathers instead.

These birds eat fish. Their white bellies help hide them from fish below. It is fun to watch them fly!

Terns are seabirds found all over the world.

You can find them near the sea, rivers, or wetlands. These birds are slender and lightly built. They have long, narrow wings and long, forked tails.

Their tails help them look elegant when they fly. Most terns have pale grey backs and white bellies. They often wear a black cap on their heads.

This white color helps them hide from fish when hunting. When seen from below, the white belly blends with the sky. Some terns are different. The Inca tern has dark feathers.

Terns use many different calls to talk. They use special sounds to warn others of danger. Parents and chicks also use calls to find each other. Even siblings can recognize each other's voices. This helps the family stay together. Terns can live for a long time. However, many species are now in trouble. They face problems from pollution and lost homes. Some terns are even endangered.

Terns are graceful seabirds found in almost every part of the world.

You can find them near the ocean, along rivers, or in wetlands. These birds belong to a group called Sterninae. This group is part of a larger family called Laridae.

This same family also includes many types of gulls and skimmers. Terns are very important because they are skilled hunters of fish. Most species are currently facing hard jobs to survive. They deal with lost homes, pollution, and new predators. Some, like the Chinese crested tern, are critically endangered.

Terns have a very specific way of looking and moving. They are slender and lightly built with long, narrow wings. Their tails are often deeply forked, which helps them look elegant in flight.

Most adults have pale grey feathers on top and white feathers below. They often wear a black cap on their heads. This white belly helps them hide from fish when they look up from below. This is a way to stay hidden while they hunt. Some species, like the Inca tern, have much darker feathers instead.

People have known about these birds for a very long time. The word "stearn" was used in Old English as early as the eighth century.

Scientists have worked for years to understand how they are related to other birds. A famous scientist named Linnaeus helped name them in 1758. He used the name Sterna for them. He called them "rostrum subulatum," which means they have an awl-shaped bill. This refers to their long, pointed bills that look like a sharp tool. This helps them tell them apart from gulls with thicker bills.

Terns come in many different sizes and shapes. The least tern is very small, weighing only about 33 grams.

On the other end, the Caspian tern can reach 1.5 kilograms.

They use many different sounds to talk to each other. A common tern makes a "kee-yah" sound to warn others of danger.

They also use a "kip" sound when they are being social. Parents and chicks use these calls to find one another. Even siblings can recognize each other's voices after twelve days.

You can think of a tern's life as a series of changes. When they are young, their feathers look scaly with dark edges.

They do not look like adults until they are about three years old. Terns also change their clothes, or plumage, after the breeding season. They grow a white forehead for the winter.

This is a bit like how we change our clothes for different weather. Their life in the air and sea is a constant cycle of growing and moving.

Terns are a diverse group of seabirds within the subfamily Sterninae. They belong to the larger family Laridae, which also includes gulls and skimmers.

These birds have a worldwide distribution. You can find them near oceans, rivers, or wetlands. Terns are known for being slender and lightly built. They have long, narrow wings and long, pointed bills. Most species feature pale grey feathers on their upper bodies and white feathers below. They often wear a contrasting black cap on their heads. This specific coloring serves a purpose during hunting. The white underparts help the bird stay hidden from fish looking up toward the sky.

The physical structure of a tern is designed for elegant flight. Their long, narrow wings and long tails make them very streamlined.

Many sea terns possess deeply forked tails, while other species have at least a shallow V-shape. The noddies, a specific genus called Anous, have even more unusual notched-wedge shaped tails. While their legs are relatively short, terns are actually capable of running well. They have webbed feet, but they rarely swim. Usually, they only land on the water to bathe.

Terns go through several distinct stages of feather growth, known as plumage. Juvenile birds look quite different from adults. They often have brown or yellow-tinged upperparts with dark edges that create a scaly appearance. They also have dark bands on their wings and shorter tails. Most species do not begin their first major moult, which is the process of shedding old feathers, until after migration. By their second summer, they look much more like adults. They usually reach full mature plumage by their third year. After the breeding season, they moult into a non-breeding plumage, which typically includes a white forehead.

There is a wide variety of tern species with different appearances. Terns range significantly in size. The least tern is very small, weighing only about 33 grams.

In contrast, the Caspian tern is much larger, reaching 1.5 kilograms.

Some species have very dark plumage instead of the typical grey and white. The Inca tern is a notable example of this atypical dark plumage.

Other species, like the black tern or the black-bellied tern, show black underparts during the breeding season. Scientists suggest that dark plumage in tropical areas might make it harder for other birds to detect them while they feed.

Humans have studied and named terns for centuries. The word "stearn" appeared in Old English as early as the eighth century. It even appears in the ninth-century poem "The Seafarer."

In 1758, the scientist Linnaeus formally recognized the distinction between gulls and terns. He placed terns in the genus Sterna. He described them as "rostrum subulatum," which means they have an awl-shaped bill. This refers to their long, pointed bills that distinguish them from the thicker-billed gulls.

Terns use a wide repertoire of vocalizations to communicate. For example, the common tern has a distinctive alarm call described as "kee-yah."

They also use a shorter "kyar" call when taking flight due to a threat. This sound helps quiet a noisy colony so residents can assess danger. Parents and chicks use specific calls to locate one another. Even siblings can recognize each other's unique voices about twelve days after hatching. These vocal differences also help humans distinguish between very similar species, such as the common and arctic terns.

While terns are long-lived and generally free from many natural predators, they face modern challenges. Most species are currently declining in number due to human activities. These activities include habitat loss, pollution, and disturbance. Introduced mammals also pose a threat through predation. The Chinese crested tern is currently classed as critically endangered.

Although international agreements offer some protection, adults and eggs are still sometimes used for food in tropical regions. Understanding the complex relationships between tern genera through DNA research continues to help scientists map their history.