Bald eagles are popular birds and have many anecdotes and stories associated with them. They do things that can be difficult to interpret.
If you’re someone who likes bald eagles you may enjoy these ten facts about America’s national symbol.
1. Bald eagles are among the most flexible and opportunistic foragers
Bald eagles choose habitats with large concentrations of fish, waterfowl, and small mammals for two reasons. One is that large concentrations of any prey make it easier to catch them. Two, large concentrations of prey invariably result in more animals dying and more carrion available to the eagles.
When foraging for food, bald eagles choose tall perches adjacent to bodies of water from where they scan the surroundings. From there, they watch for fish that are swimming near the water surface or floating dead or about to die.
Bald eagles are good at detecting waterfowl or seabirds, such as gulls wounded or struggling to move. Upon detection, they quickly launch an attack at the struggling bird for a quick and easy catch.
They can switch their diets to mostly fish, mostly waterfowl and small mammals, or both depending on the availability of these food items.
2. Bald Eagles Eat Mostly Fish
In spite of having a strong hooked beak and strong talons, the bald eagle eats mostly dead or dying fish. They are part of the group of fish eagles, which include the African Sea (Fish), Eagle (Haliaeetus vocifer), and Steller’s Sea Eagle (haliaeetus pelagicus). As their name suggests, fish is an essential part of all these eagle’s diet.
Across its range, fish constitute between 25 to 65 percent of a bald eagle’s diet. But this varies with the locality and the type of food that is more prevalent.
On the other extreme are eagles in Yosemite National park, where fish is not readily available, and eagles here feed primarily on large mammal carrion
3. Bald eagles can be kleptoparasitic
Kleptoparasitic comes from the word Kleptomaniac, which means having an impulse to steal. While eagles do not have the urge to steal food from other birds, they supplement their food intake with food procured by other birds. This habit intensifies when food is scarce.
While scanning their surrounding from tall perches, eagles also watch for what other birds are doing. If a gull catches a fish or other type of food, a bald eagle is likely to chase the gull until it lets go of its food to let the eagle have it.
Bald eagles also chase eagles of lower hierarchies, e.g., juvenile birds, to take their catch (see photo above).
4. Occasionally, bald eagle predate on livestock
Bald eagles have been implicated in predatory situations involving young pigs, goats, and sheep. With only a few cases confirmed and the blame typically shifted to golden eagles (Aquila chrysotus), there is no doubt bald eagles can predate on livestock.
Bald eagles regularly hunt for rats, rabbits, and similar-sized mammals. With human expansion onto eagle habitats, domestic kittens have become part of bald eagles’ diet. Young domestic cats are much easier to catch and handle than wild rabbits, and bald eagles always prefer prey that is easy to catch.
The increasing popularity of organic eggs and chickens, pasture-raised poultry is a growing trend. Depending on the area in the country, bald eagles and other raptors have discovered an easy and reliable source of food in flocks of unsuspecting farm chickens.
5. Bald eagles are the largest North American “actual” bird of prey
Although by a relatively small margin, the bald eagle is the largest North American bird of prey.
Ornithologists define a “bird of prey” as one that primarily pursues, hunts, kills, and feeds on life animals using its strong talons, an acute sense of vision, and strongly hooked beak adapted to tear flesh from their prey.
Birds of prey belong to the orders Falconiformes and Strigiformes.
The much larger California Condor (Gymnogyps californianus) is North America’s largest flying bird, and while regarded as a bird of prey by some, technically, they are not.
California condors, along with black and turkey vultures, belong to the order Cathartiformes and are not true birds of prey. They have long wings, which makes them similar to a bird of prey in flight, but do not hunt and pursue their prey, have weak talons unable to grasp things, and feed entirely on carrion.
Table showing differences in weight and wingspan between bald and golden eagles.
|Bald Eagle||Golden Eagle|
|Weight||Male: 10 lb Female: 12 lb||Male: 8.1 lb Female: 11.4 lb|
|Wingspan||Range: 71 – 91 Av: 81 in||Range: 71 – 92 Av: 81.5 in|
6. The Bald Eagle is America’s most successful conservation story
Since 1782, the bald eagle has been the national symbol of America. Bald Eagles did not become an emblem of the environmental movement until the 1960s and 1970s, when their numbers declined steeply from the effects of ingesting the pesticide DDT. As soon as DDT was banned and the eagle was fully protected under the Endangered Species Act, eagle numbers began to rebound rapidly. Bald Eagles were removed from the federal list of endangered species in 2007 by the U.S. Fish and Wildlife Service.
Federal regulations concerning the Bald Eagle’s management did not end when the species were taken off the threatened and endangered species. Bald and Golden Eagles were now governed by a new statute, the Bald and Golden Eagle Protection Act.
Bald eagles now confront the risk of lead poisoning. A hunter’s gut piles and unrecovered carcasses are tempting food to scavenging eagles. Many carcasses contain lead fragments, which the eagle and other scavengers ingest along with the meat. Eagles can be killed with very small quantities of lead contamination in their food.
The threat of lead poisoning motivated the 1991 ban on lead shot in waterfowl hunting, so Bald Eagles would not be exposed in their preferred habitats of wetlands and lakes.
Although the future is impossible to predict, bald eagle biologists remain confident that what lies ahead holds promise.
7. Bald Eagles hold the world record for the largest tree nest ever recorded
As far as nest size goes, the bald eagle has the world record as the largest nest ever recorded, not just for a bird but for animals of all kinds.
The bald eagle constructs nests that are reused every year. At the beginning of every breeding season, the eagle pair adds nesting material to the existing nest, which increases its size and depth.
Bald Eagles can nest in a single nest for 30 years. The table below shows the measurements of the largest, heaviest, and oldest bald eagle nests known in North America.
|Nest Diameter||Nest Depth|
|A typical Bald Eagle nest||1.5 – 1.8 m (4.9-5.9 ft)||0.7-1.2 m (2.3-4 ft)|
|The oldest eagle nest ever|
Locality: Vermillion, Ohio. Used by Bald Eagles for 34 years.
2.7 m (8.8 ft)
|3.6 m (12 ft)|
Estimated Weight:Two metric tons.
|Largest Nest on Record.Locality: St. Petersburg, Florida.||2.9 m (9.5 ft)||6.1 m (20 ft)|
See more about bald eagle nests.
8. Young bald eagles live a nomadic lifestyle
Immature bald eagles spend their first four years of life on the prowl exploring extensive territories. Once they begin to catch their own food, young eagles start venturing away from the nesting territory. During the first four years, they wander in all directions as they do not need to defend a territory, nor are they tied to any particular place.
Young birds wander in search of food. They remain where food is plentiful and easy to obtain. Food availability is the primary driver of migration. Young birds tend to stay at suitable places as long as the food is available. Once food becomes scarce, and the competition is fierce, birds start to search for the next best spot. They can cover thousands of miles to find good feeding spots.
After approximately four years, young eagles tend to go back to the nest territory where they were born. A concept called “site-fidelity” means a strong attraction for a bird to return to the area where it was born.
Whether a young bald eagle settles on or near its place of birth depends on many factors such as the existing available habitat and density of eagles (i.e., can the habitat take one more pair?). Depending on how suitable the area is for a new territory, the young eagles settle near where they were born or at the next best adjacent territory.
9. The bald eagle was nearly replaced as the national symbol
Myth or reality?
As the story goes, Benjamin Franklin recognized the wild turkey’s fascinating characteristics and appeal when he suggested the bird be our nation’s national bird. Even though the turkey lost by just one vote, it is still a favorite game bird in America because of its keen senses.
If Franklin had succeeded, we might have seen the wild turkey (Meleagris gallopavo) as the national symbol.
Franklin dissed the bald eagle for its thieving tendencies and vulnerability, especially being harassed by small birds. In a letter, he wrote about how he wishes the Bald Eagle hadn’t been chosen as the representative of our country. “Sadly, the bald eagle has a bad moral character. He does not earn his living honestly. … Besides, he is a rank Coward: The little King Bird not bigger than a Sparrow attacks him boldly and drives him out of the District.”
On the other hand, Franklin called the turkey the most respectable of all birds and a true original native of America. Franklin viewed the eagle as a coward and believed that “the turkey would not hesitate to defend his farmyard if he saw a grenadier from the British Guards entering with a red coat on.”
According to some historians, the story about Benjamin Franklin wanting the National Bird to be a turkey is just a myth. Franklin wrote a letter to his daughter criticizing the Great Seal’s original eagle design, claiming it looked more like a turkey.
Franklin never publicly stated his views about the turkey. When the opportunity came up to propose an official symbol for the United States, he claimed his idea was biblical rather than avian.
10. Bald Eagles can live for nearly four decades in the wild
It is widely known that animals in captivity live longer than those in the wild. Some eagles have lived as long as 50 years in captivity. The oldest known bald eagle in the wild was hit by a car in New York in 2015. This bird was banded in New York in 1977, which indicates that the bird was at least 38 years of age.