The bald eagle characterizes an example of power and superiority, freedom and greatness. The bird of prey of North America is one of the national symbols of the United States and belongs to the hawk family. The Indians identify the bird with a deity, many legends and rituals are associated with them. Its images are applied to helmets, shields, dishes and clothes.
The origin of the species and description
In 1766, the Swedish naturalist Carl Linnaeus classified the sea eagle as a falcon and named the species Falco leucocephalus. 53 years later, the French naturalist Jules Savigny included the bird in the genus Haliaeetus (literally translated as sea eagle), which until then consisted only of the white-tailed eagle.
Both birds are close relatives. Based on molecular analysis, it was revealed that their common ancestor separated from the rest of the sea eagles about 28 million years ago. Among the oldest fossils of the now existing species are those found in a cave in Colorado. According to scientists, they are about 680-770 thousand years old.
Video: Bald Eagle
There are two subspecies of the bald eagle that differ only in size. A larger subspecies is distributed in Oregon, Wyoming, Minnesota, Michigan, South Dakota, New Jersey, Pennsylvania. The second race lives on the southern borders of the United States and in Mexico.
Since 1972, the profile of this bird has been featured on the Great Seal of the United States. Also, the image of a bald eagle is printed on banknotes, coat of arms and other state signs. On the coat of arms of the United States, a bird holds an olive branch in one paw, as a sign of peace, and an arrow in the other, as a symbol of war.
Appearance and features
Bald Eagles enter among the largest birds in North America. At the same time, they are significantly inferior in size to their relative – the white-tailed eagle. Body length reaches 80-120 cm, weight 3-6 kg, wingspan 180-220 cm. Females are 1/4 larger than males.
Birds living in the north of the range are much more massive than those living in the south :
- in South Carolina, the average weight of birds is 3.28 kg;
- in Alaska, 4.6 kg for males and 6.3 for females.
The beak is long, yellow-golden color, hooked. The growths on the eyebrows give the eagles a frowning expression. Paws are bright yellow, without plumage. Sharp claws on strong long fingers. The rear claw is well developed, thanks to which they can hold prey with their front fingers, and with their back, like an awl, pierce the vital organs of the victim.
The eyes are yellow. The wings are wide, the tail is medium in size. Young birds have a dark head and tail. The body may be white-brown. By the sixth year of life, the feathers acquire a characteristic color. From this age, the head and tail become contrastingly white against the background of an almost black body.
Only hatched chicks have pink skin, grayish fluff in some places, flesh-colored paws. Three weeks later, the skin becomes bluish, the paws turn yellow. The first plumage is chocolate. By the age of three, white marks appear. By the age of 3.5, the head is almost white.
For all its harsh appearance, the voice of these birds is weak and squeaky. The sounds they make are like whistles. They are referred to as “quick-kick-kick-kick.” In winter, in the company of other eagles, birds are very fond of chirping.
Where does the bald eagle live?
Bird habitats are found mainly in Canada, the United States and northern Mexico. Also, populations are noted on the French islands of Saint-Pierre and Miquelon. The largest number of bald eagles in places near oceans, rivers and lakes. Sometimes individual individuals appear in Bermuda, in Puerto Rico, Ireland.
Until the end of the 20th century, birds of prey were observed in the Russian Far East. During the expedition of Vitus Bering, a Russian officer in his report indicated that the researchers who had to spend the winter on the Commander Islands ate the meat of eagles. In the 20th century, no signs of nesting were found in these places.
The habitat of birds of prey is always located near large bodies of water – oceans, large rivers and lakes, estuaries. The length of the coastline is at least 11 kilometers. For a nesting pair, a pond with an area of at least 8 hectares is required. The choice of territory directly depends on the amount of food that can be obtained here. If the place is rich in prey, the density will be high enough.
Birds nest in coniferous and hardwood forests, no more than 200 meters from the water. To build a nest, they look for a massive tree with a wide crown. During the breeding season avoid places where people often visit, even if it is an area with a high amount of prey.
If the reservoir in the occupied territory is covered with ice in winter, bald eagles migrate to the south, to a place with a milder climate. They wander alone, but for the night they can gather in groups. Although partners fly separately, they find each other during wintering and nest again in pairs.
What does the bald eagle eat?
The diet of birds of prey consists mainly of fish and small game. If possible, the eagle can take food from other animals or eat carrion. On the basis of a comparative analysis, it was proved that 58% of all food consumed is fish, 26% is for birds, 14% for mammals and 2% for other groups. Eagles prefer fish to other types of food.
Depending on the state, birds eat:
- coho salmon;
- Pacific herring;
- large-lipped chukuchan;
- black pike;
- smallmouth bass.
- herons .
Sometimes they attack large individuals, such as white goose, sea gull, white pelican. Due to the weak protection of concentrations of colonial birds, eagles attack them from the air, grabbing both chicks and adults on the fly, they can steal and eat their eggs. Mammals account for a small proportion of the diet.
Leaving carrion aside, all eagle prey is no larger than a hare:
Some individuals living on the islands can hunt seal cubs, sea lions, and sea otters. Attempts to hunt livestock have been recorded. But still they prefer to bypass humans and hunt in the wild. Eagles do not engage in an unequal battle with large and strong animals.
Still, there is documented evidence of a single case when a bald eagle attacked a pregnant sheep weighing over 60 kilograms.
Features of character and lifestyle
The predator hunts mainly in shallow water. From the air, he notices prey, dives sharply down and grabs the victim with a tenacious movement. At the same time, he manages to wet only his legs, the rest of the plumage remains dry. The speed of a normal flight is 55-70 kilometers per hour, a dive – 125-165 kilometers per hour.
The weight of their prey usually varies between 1-3 kilograms. Although there is a reliable mention in the literature of how a predator carried a baby deer weighing about 6 kilograms, setting a kind of record among its species. They have spikes on their fingers to help hold prey.
If the burden is too heavy, it pulls the eagles into the water, after which they swim to the shore. If the water is too cold, the bird may die of hypothermia. Eagles can hunt together: one distracts the prey, and the other attacks it from behind. They prefer to take their prey by surprise.
Bald eagles are known for their ability to take food from other birds or animals. The food obtained in this way makes up to 5% of the total diet. In view of the lack of hunting experience, young individuals are more inclined to such actions. In the course of a conflict with those from whom the eagles stole their prey, the owners of the food can be eaten themselves.
In the wild, the life expectancy of predatory birds is 17-20 years. Until 2010, the oldest bald eagle was considered a bird from Maine. She was 32 years 11 months old at the time of her death. Birds in aviaries live much longer – up to 36 years.
Social structure and reproduction
Puberty occurs around 4-7 years. Bald eagles are exclusively monogamous birds: they mate with only one female. It is believed that partners are faithful to each other throughout life. However, this is not quite true. If one does not return from wintering, the second is looking for a new pair. The same thing happens when one of the pair is unable to reproduce.
During the mating season, the birds defiantly chase each other, tumble in the air and perform various tricks. The most spectacular of them is when the partners cling to each other with their claws and, spinning, fall down. They open their fingers only at the very ground and again soar upward. A male and a female can sit together on a branch and rub their beaks against each other.
After the formation of a pair, the birds choose a place for the future nest. In Florida, the nesting season begins in October, in Alaska from January, and in Ohio from February. The bird house is built in the crown of a living tree near water bodies. Nests can sometimes grow to incredible sizes.
Bald eagles build the largest nests in North America. One of them is listed in the Guinness Book of Records. It was 6 meters high and weighed over two tons.
A month after the start of construction work, females lay from 1 to 3 eggs at intervals of up to two days. If the clutch is destroyed, the females lay eggs again. After 35 days, the chicks hatch. Due to the difference in deposition, some are born earlier, others later. The female is always in the nest and feeds the babies. The male gets food.
By 6 weeks, the chicks themselves know how to tear the meat, and by 10 they make their first flight. In half of them, it ends in failure and the kids spend a few more weeks on the ground. After they learn to fly, the chicks stay with their parents for a while, and then they fly away.
Natural enemies of bald eagles
Because birds of prey are at the top of the food chain, they have practically no natural enemies other than humans. Nests can be destroyed by raccoons or owls, wanting to eat eggs. If the home of the eagles is located on the ground, arctic foxes can attack it.
During the times of mass migration, settlers hunted birds for sport and shot them because of their beautiful plumage. In their habitats, trees were cut down and the coasts were built up. Due to the growing number of settlements, water supplies were depleted. This led to the destruction of places where birds lived many decades before.
The Ojibwe Indians believed that the bones of the eagles helped to get rid of diseases, and the claws were used as jewelry and amulets. Feathers were given to warriors for special merits and passed down from generation to generation. Birds were considered God’s messengers.
Farmers disliked eagles because of attacks on domestic birds. They also believed that raptors caught too many fish from the lakes. To protect against them, the inhabitants sprinkled the carcasses of livestock with poisonous substances. By 1930, the bird had become a rarity in the United States and lived mainly in Alaska.
At the end of the Second World War, the insect poison DDT began to be used in agriculture. Birds involuntarily consumed it with food, as a result of which the calcium metabolism in their body was disturbed. The eggs became too fragile and broke under the weight of the female.
Population and species status
Before Europeans settled on the North American continent, about 500,000 bald eagles lived here. The artist John Audubon published an article in his journal in the mid-19th century expressing his concern about the shooting of birds. He turned out to be right, eagles have become a rare species in the United States.
In the 1950s, there were close to 50,000 predators. After the use of chemicals that had a very detrimental effect on sea eagles, an official count was made in the early 60s, during which 478 breeding pairs were recorded.
In 1972, the authorities imposed a ban on this poison and the number became recover rapidly. In 2006, the number of pairs increased more than 20 times compared to 1963 – up to 9879. In 1992, the number of eagles worldwide was 115 thousand individuals, of which 50 thousand lived in Alaska and 20 in British Columbia.
The conservation status of predators has repeatedly changed. In 1967, in the south of the range, the birds were recognized as an endangered species. In 1978, the status extended to all continental states, excluding Michigan, Oregon, Wisconsin, Minnesota and Washington.
In 1995, the conservation status was reduced to Vulnerable. In 2007, after the restoration of numbers, he was excluded from both categories. The 1940 law on the protection of eagles is still in force, because the habitat is shrinking every year, and poachers do not stop hunting birds.
Bald Eagle Protection
In the International Red Book, the species is categorized as Least Concern. In the Red Book of the Russian Federation, he was assigned an indefinite status (category 4). A number of international agreements and the Convention on International Trade in Prohibiting Species advocate for the protection of the species.
Since 1918, there has been an agreement between the US and the UK to ban the shooting of more than 600 species of migratory birds. In 1940, the bald eagle was added to it. Everywhere there was a law punishing the destruction, trade and possession of birds or their eggs. Canada has a separate law prohibiting any possession of birds or their organs.
Written permission from the Eagle Exhibition is required to own a bird in the US. However, the license is not issued to anyone, but only to government organizations such as zoos, museums, scientific communities. Valid for 3 years. The organization must provide the birds not only with the most comfortable conditions, but also with a staff of specially trained workers.
At the end of the 20th century, when the threat to the survival of the species loomed, many programs were created to breed the species in captivity and release chicks in wild nature. Ornithologists have created dozens of pairs. They transferred the first clutch to the incubator, the second was incubated by the females. Over the lifetime of the program, 123 individuals have been raised.
Today, the bald eagle is ubiquitous in United States trappings such as army banners, presidential standards, the one dollar bill, and the 25 cent coin. The image is used by private businesses to claim American origins, such as American Airlines or Pratt Whitney.