Eagles are striking and majestic, but they're also highly intelligent and exhibit some very interesting behaviors. Here are ten things you may not know about these wonderful birds.
#1. Beaks Change Color
Bald eagles aren’t born with yellow beaks. Instead, their beaks gradually move towards the classic yellow shade as they mature, with the average bald eagle displaying a fully yellow beak by age four. Their Eyes gradually change from dark brown to yellow while the beak goes through its color change as they mature as well.
#2. Superb Vision
The eyes of eagles are very large in proportion to their heads, and their pupils are particularly big. These impressive organs allow them to see five colors rather than just our three basic colors, and their eyes have five times more light-sensitive cells in the retina. Although an eagle may only weigh about 10 pounds, its eyes are roughly the same size as those of a human. An eagle can see something the size of a rabbit more than three miles away. Given these facts, it’s unsurprising that eagles are said to have the best vision in the animal kingdom.
There is a scientific set-up to determine the acuity of an eagle’s eyesight. The birds are trained to fly down a long corridor where two screens are installed at the end. One screen has a display of striped patterns to attract the eagle towards it. The Eagles’ acuity is tested by making micro changes to the width of the stripes and determining from what distance the eagles begin to turn in the correct direction.
#3. Extreme Nest Building Skills
A bald eagle’s nest can be seriously large! These birds build their nests in trees, but the nests are so heavy that they have been known to break the trees. The typical bald eagle nest has a diameter of five feet and a depth of six feet, but the largest of these nests measured 9.6 feet by 20 feet and was over two tons. Since it takes a great deal of time and effort to build these nests, bald eagles prefer to use the same nest for years in a row (sometimes even for decades).
#4. Dramatic Mating Rituals
When bald eagles are trying to attract mates, they engage in impressive displays involving steep swoops, violent dogfights and other displays of their strength and agility. The most famous and recognizable of these rituals is the “cartwheel courtship flight,” in which two bald eagles will fly up high, lock talons and then get into a cartwheel spin as they fall toward the ground, breaking apart at the last minute.
#5. Fast As Fast Can Be!
Bald eagles can fly at up to 160 km/hr (100 mph), while other eagle species have been clocked up yo200 miles (230 kilometers) per hour. Most eagles have wings that are rather wide and quite long. This helps them to soar and glide with much less effort. At low speeds, these broad wings can hold the eagle up longer than birds with narrow wings. These broad wings also provide extra lift when an eagle has to carry its prey up into the air.
#6. A Symbol Throughout History
Eagles have always been viewed as symbolizing freedom and power. For example, ancient Aztecs would choose to build cities where eagles landed, and Native Americans gave eagle feathers as signs of respect. Eagle conveys the powers and messages of the spirit – it is man’s connection to the divine because it flies higher than any other bird. Notably, The bald eagle has been the national bird of the United States since 1782.
#7. Bald Eagles Don’t Sound Like They Do In The Movies
Although you might think that the stunning bald eagle would have an equally impressive call, the surprising truth is that these birds have a rather weak call. When filmmakers want to make a scene with a bald eagle seem more dramatic, they often use the call of the red-tailed hawk.
#8. Creative Problem Solvers
Some eagle practices are harsh but effective. For example, golden eagles in Greece have been spotted killing turtles by dropping them down onto rocks. This process breaks their shells and allows eagles to eat the meat. Meanwhile, eagles often lay more than one egg and let the stronger, larger chick kill the weaker offspring. In contrast, the African vulturine fish-eagle is mainly vegetarian and eats oil palm fruits.
#9. Females Are Larger
Female eagles tend to be larger than male eagles. It is thought that the size difference is explained by the fact that males do more flying and hunting (and therefore benefit from a sleeker body shape).
#10. Life Partners
Eagles are a fairly monogamous species and many pairs of eagles mate for life. One study found that 90% of these birds stayed with partners until a partner died, and then they moved on. Bald eagles specifically stay hitched until death do they part, often returning year after year to the same nest. While they are there, the pair will continually add to the structure. After many seasons it assumes gargantuan proportions and stands as a symbol of their life long fidelity.