Bald eagle

National Geographic

2 days ago

Scientific Name: Haliaeetus leucocephalus Average Life Span In The Wild: 20 to 30 years Size: Body: 28 to 38 inches; Wingspan: 80 inches Size relative to a 6-ft human:
The bald eagle is a large, powerful bird of prey that has been the national symbol of the United States since 1782. That year, it appeared with outspread wings on the country's Great Seal as a sign of strength.
Bald eagles don't actually have bare heads. Their name comes from the old English word 'balde,' which means white—a nod to the snowy-white feathers that cover their heads and tails.
Most of these majestic, dark brown-bodied creatures live in Alaska and Canada. But there are also eagles in the lower 48 states (except Hawaii) and Mexico.
Bald eagles are famous in the U.S. However, they almost disappeared in the middle of the 20th century from decades of sport hunting and habitat destruction.
DDT, a pesticide that became popular after World War II, also wreaked havoc on bald eagles. They ate contaminated fish, which weakened their eggshells so much, they would crack during incubation.
In 1972, the U.S. banned DDT use and began intensive population management strategies. These conservation efforts helped them recover in the wild and led to their removal from the Endangered Species Act list in 2007.
(Most U.S. eagles suffer from lead poisoning, study suggests.)
Today the population estimate for bald eagles is about 316,700. The numbers continue to soar despite threats like illegal hunting and electrocution from power lines. A 2019 survey by the U.S. Fish and Wildlife Service found that the bald eagle population quadrupled since 2009.
Bald eagle habitat and diet
Bald eagles occasionally live in dry areas. However, most reside in woods by rivers, lakes, and other bodies of water. These areas tend to be rich with fish—their main food source. Their diets also include birds, turtles, and small mammals, such as squirrels and rabbits.
To conserve energy, these opportunistic creatures sometimes eat dead animals. They also steal prey from birds and other animals, even though they are skilled hunters themselves.
Bald eagles are raptors, like hawks and falcons, with special features that help these predatory birds chase their prey.
Razor-like talons puncture and can carry prey up to half the eagle's body weight, roughly eight to 13 pounds. A large wingspan conserves energy by soaring. A dense coating of light-detecting cells on their retinas helps them spot prey from up to a mile away.
(Winter is prime time for watching bald eagles—here's where to spot them.)
Once an eagle has captured a meal, it uses the sharp edges of its curved beak to slice through flesh or scales.
Bald eagle breeding and family life
Most bald eagles reach sexual maturity at age four or five and breed in early spring. Breeding pairs bond by performing dance-like air displays.
In one example, during the 'cartwheel courtship flight,' a pair flies high into the sky. They lock talons and spin downward, then break off just before hitting the ground.
Those teamwork skills come in handy when it's time to build nests. These stick structures lined with grass and other materials can take several months to construct.
Most couples choose the tops of tall trees for nesting sites, where there's enough support for these enormous structures. At about six feet wide and four feet deep, bald eagle nests are the largest of any bird in North America. Pairs living in treeless areas build nests on cliffs or, on rare occasions, the ground.
(See photographs depicting the everyday lives of this national symbol.)
Bald eagle couples mate for life and return to these sturdy homes each year to care for a new pair of baby eagles, called eaglets. Both parents play an active role in rearing. They deliver prey, place torn-up food into eaglet beaks, and fiercely guard little ones from predators, such as raccoons and ravens.
Like golden eagles, baby bald eagles are completely brown. They don't develop the distinctive white markings of their parents until they reach five years of age. They begin to fly at about 10 to 12 weeks and permanently leave the nest a month later.
Bald eagle behavior
Untethered to a breeding site, young eagles tend to roam far from their nests in directions that appear random. Adult birds are more intentional, migrating only as far as necessary to find sustenance. When lakes and rivers freeze, for example, Northern bald eagles fly to the coast or south to open water.
These territorial birds typically travel alone. However, during non-breeding times, such as in the winter, eagles often roost together in groups ranging from several to hundreds of birds.
Scientists think they congregate to socialize or gain information about the location and availability of prey. To communicate, bald eagles emit a variety of whiny, high-pitched vocalizations that may sound surprising coming from such brawny bodies.
5 interesting facts about bald eagles
Like other birds of prey, bald eagles exhibit 'reverse sexual size dimorphism,' which means that females are larger than males. —Audubon Center for Birds of Prey
Bald eagles swim by moving their wings in a rowing motion that looks similar to the butterfly stroke. —NPR
Bald eagles store excess food in a crop, a muscular pouch below their throat that looks like a bulge from the outside. —American Eagle Foundation
In 1784, Benjamin Franklin wrote a letter to his daughter saying the bald eagle was a poor choice for the U.S. national symbol because of its thieving tendencies. —The Franklin Institute
Female bald eagles lay one to three eggs. Both parents take turns incubating them, which takes about 35 days. —U.S. Fish & Wildlife Service
How rare is it to see bald eagles?Thanks to conservation efforts, bald eagles were removed from the endangered species list in 2007. You can see them in wildlife refuges throughout North America and in the wild. In Alaska, bald eagles are almost a common sight.
—U.S. Fish & Wildlife Service
What is the penalty for killing a bald eagle? The Bald and Golden Eagle Protection Act, enacted in 1940, prohibits anyone from harming bald eagles in any way. Doing so risks a $100,000 fine ($200,000 for organizations) or imprisonment, or both. The act defines harm in many ways, including pursuing, capturing, and even disturbing their nests or nesting sites outside of breeding season.
—U.S. Fish & Wildlife Service
Can a bald eagle pick up a 25lb. dog? No, bald eagles cannot pick up a 25-pound dog. They can carry up to half their body weight, roughly eight to 13 pounds.
—American Eagle Foundation
This story originally published on September 23, 2019. It has been updated.