White-tailed eagle

The white-tailed eagle (Haliaeetus albicilla), sometimes known as the "sea eagle", is a large bird of prey found across temperate Eurasia. It belongs to the family Accipitridae, which includes other birds like hawks, kites, and harriers. There are up to eleven species called sea eagles, and this one is also called the white-tailed sea-eagle, ern, erne, gray sea eagle, or Eurasian sea eagle.

These eagles live near large bodies of water such as coastal saltwater areas, freshwater lakes, wetlands, bogs, and rivers. They need tall, old trees or sea cliffs for nesting and eat mainly fish and water birds. They are strong hunters but also sometimes eat food left by other animals.

In the past, white-tailed eagles were harmed by human actions such as changing their habitats, destroying wetlands, and using harmful pesticides. Because of this, their numbers dropped in many places. However, thanks to protection efforts by governments, conservationists, and careful reintroductions, some populations have begun to grow again. These eagles are powerful predators and share a similar way of living with the bald eagle found in North America.

Taxonomy

The white-tailed eagle was first described by the Swedish naturalist Carl Linnaeus in 1758. The scientific name Haliaeetus means "sea-eagle", coming from ancient words for "sea" and "eagle". The species name albicilla refers to its white tail. This bird has many names in different languages, such as erne in Anglo-Saxon, which means "soarer".

Systematics

The white-tailed eagle belongs to the genus Haliaeetus, which includes 11 living species. It is closely related to the lesser and grey-headed fish eagle, which mainly eat fish and live in wooded, mountainous areas. These fish eagles look different from typical sea eagles, being slimmer, longer-tailed, and more uniformly grey.

The white-tailed eagle also shares a close relation with the bald eagle. These two species likely diverged from other sea eagles around the early Miocene period, about 10 million years ago. They probably originated in the North Pacific and then spread westward into Eurasia and eastward into North America. Like another large northern species, Steller's sea eagle, adult white-tailed eagles have yellow feet, beaks, and eyes.

Description

The white-tailed eagle is one of the largest living birds of prey. It is the largest eagle in Europe and among the largest in the world, though it is smaller than the Steller's sea eagle, harpy eagle, and Philippine eagle. This impressive bird can measure from 66 to 94 cm in length, with a wingspan ranging from 1.78 to 2.45 meters. Males typically weigh between 3.1 to 5.4 kg, while females are slightly larger, weighing from 4 to 6.9 kg.

White-tailed eagles have a distinctive appearance. Adults are mainly greyish-brown with a pale head and neck, and they have a striking white tail. Their wings are very broad, and they are skilled soarers. These eagles are vocal during the breeding season, with males and females having different calls that they often use together in duets.

Distribution and habitat

White-tailed eagles live in many parts of northern Europe and Asia. They breed in places like Norway, Finland, Sweden, and Denmark, as well as many islands and coastal areas. They are also found in Russia, stretching all the way to the Bering Sea. Some live in Turkey, Iran, and parts of Central Asia.

These birds prefer areas near water, such as coasts, lakes, and rivers. They like to nest in tall trees or on cliffs and can be found in both remote forests and sometimes near human communities, especially if the area is protected.

Behaviour

White-tailed eagles spend much of their day perched on trees or crags, often staying in one place for hours. They alternate between soaring in the sky and perching, especially over water or moist areas, but they soar less than golden eagles. These eagles often roost together near their nests, choosing spots like crags, trees, or ledges.

Young white-tailed eagles may travel far from their birthplaces, especially in Europe, while adults often stay close to their nesting areas year-round. In some regions, these eagles migrate, traveling long distances to wintering grounds. During winter, they sometimes gather in groups, especially younger birds. These eagles defend their territories strongly, and males may fight fiercely if another enters their area.

Dietary biology

The white-tailed eagle has a varied diet that changes with the seasons. They mainly eat fish and birds, but will also eat mammals, especially when fish are less available in winter. These eagles are strong hunters and can catch large prey, but they often look for easier targets that are vulnerable or injured.

White-tailed eagles are skilled at fishing, especially in shallow waters, and they also scavenge for dead fish and other animals. They can eat a lot at once, sometimes up to 10% of their body weight in a single meal. Their diet includes many types of fish, such as pike and bream, and many kinds of birds, including ducks, geese, and even larger birds like swans and herons.

In some areas, mammals like rabbits and hares make up a big part of their diet, especially when other food is scarce. They can also eat small rodents, sometimes even tiny ones like shrews. Occasionally, they might eat other animals like reptiles or amphibians, but this is less common.

Overall, white-tailed eagles are flexible hunters, able to find food in many different ways, which helps them survive in various habitats.

Breeding

White-tailed eagles breed between January and July in the southern parts of their range and from April to September in the northern parts. These birds mate for life, often performing aerial displays and calls to strengthen their bond. Their nests are large structures built in tall trees or on cliffs, preferred for their access to food and safety.

Eggs are laid between January and May, depending on the region, with most clutches containing two eggs. Incubation lasts about six weeks, primarily by the female. Chicks hatch and are cared for by both parents, with the male often bringing food. The young birds stay near their parents for several months after fledging, learning to hunt and survive on their own.

Relationship with humans

The white-tailed eagle once lived across much of Europe and parts of Africa but faced a big drop in numbers from the 19th century onward. By the early 1900s, they were almost gone from Europe except in places like Fennoscandia, mainly Norway, and some spots in eastern Europe. They disappeared completely from the British Isles.

People often didn’t like white-tailed eagles because they thought the birds would eat livestock or compete with fishermen. This led to laws that allowed people to kill the eagles. Traps and guns were used, and many eagles were killed. Also, chemicals like DDT used in farming made it hard for the eagles to build strong eggs, which hurt their ability to have chicks. Heavy metals like mercury and lead from pollution also posed problems.

Conservation efforts have helped the white-tailed eagle bounce back in many places. Protecting their nests, feeding them clean food, and making laws against poisoning have all been important. In some areas, like Scotland and Ireland, people have been releasing young eagles to help the population grow again. These efforts have had success, with eagles now breeding in places where they hadn’t for many years.

Despite these wins, some threats remain. In places like Scotland, some people still illegally kill eagles, and wind turbines have started causing problems by killing eagles that fly into them. But overall, conservation work has been making a big difference, and white-tailed eagle numbers are rising in many parts of their range.

Heraldry

The white-tailed eagle has appeared in folklore and artwork for a very long time, especially in ancient Saxon culture. Many landmarks are named after this impressive bird. It is thought to be the white eagle shown in the Polish coat of arms. In heraldry, the sea eagle is often shown holding a fish, typically a pike, in its talons, which helps to tell it apart from other kinds of eagles.

The white-tailed eagle also appears in the coat of arms of Kumlinge and Åland.

Prehistory

On Orkney, Scotland, scientists have found bones of sea eagles in burial mounds that are about 6,000 years old. One of these places is called the Tomb of the Eagles. This finding suggests that ancient people in that area respected these birds. There are also old carvings made by the Picts, a group of people from long ago, that show sea eagles. In Krapina, scientists found marks on the talons (the parts like claws) of white-tailed eagles that show Neanderthals may have used them as jewellery.

Folklore

In the Shetland Isles, Scotland, some fishermen had a belief about the white-tailed eagle. They thought that when a sea eagle appeared, fish would come to the surface. Because of this belief, some fishermen would use eagle fat on their bait, hoping it would help them catch more fish.