Bald Eagles: A Top Predator Explained
Familiar Huge Sea Eagle has Startling Secrets
An Adult Bald Eagle surveys Hammond Bay in Nanaimo, BC
Bald eagles are a spectacular yet familiar bird in North America, especially the Pacific Northwest. While they are often thought of as fish eaters, their ability to capture prey is incredibly diverse. With a six to eight foot wingspan, Bald Eagles may reach 28 years in age and hold a long history as important cultural symbols.
Bald Eagles are also not as unique as one might believe in the scheme of global ornithology. These birds of prey are classified as sea eagles, which makes them close relatives of the White-tailed eagle, a native of Eurasia. African fish eagles are also related to the Bald eagle with a somewhat comparable appearance. Bald eagles have especially sharp bills to cut through tough fish prey, while their talons are specifically adapted to seize fish. The exceptional sharpness of the bill as shown in the photo makes short work of even the toughest scales and skin.
Bald eagles hold hunting superpowers, so few prey-sized animals are safe. Over 400 prey species are hunted by Bald Eagles. Bald eagles bring down geese, herons, cranes and pelicans from time to time, while ducks and gulls are fairly regularly attacked. The author has observed Bald eagles making multiple swoops to tire and catch gulls and ducks on several occasions but in these instances, the intended prey escaped. In one case, a Gadwall, a dabbling duck was caught but then struggled free. Other birds of prey, including hawks, falcons and owls may be taken by Bald eagles.
There even is a remarkable case where a Bald eagle attacked a Harbor seal off Victoria, BC in May 2020. Land mammals targeted include young deer, foxes, rabbits, raccoons, squirrels, armadillos and sometimes, various domestic animals, though this is not common and is no reason to persecute the birds, which is illegal and carries stiff penalties for violators of the criminal laws that protect Bald eagles. Bald eagles do not hunt humans but will given that impression when they attack in defence of their nests. Bald Eagles need to be protected from nest disturbance and require retention of large trees near waterways so they can have a place to nest near their feeding areas. Planners should remember recruitment: young trees need to be retained near waterbodies so they can mature into nest trees as older nest trees die and eventually come down!
Nest building is another Bald eagle superpower. The nests created by these birds hold not only the record for largest bird nest in the world but also largest tree nests any animal species makes. Nests may be 13 ft in depth, over 8 feet in width and weigh 1.1 tons. For this reason, having a bald eagle nest fall on you would be bad news indeed.
If this were not enough, there is another surprise. Females rule the roost. Male songbirds are more colorful than females, but eagles see a scenario where females are 25 percent greater in size than males. Juvenile eagles are the cause of countless false reports of Golden eagle sightings, given their lack of the characteristic white head. Closer inspection will reveal the lack of feathering on the lower legs and duller coloration among the distinguishers between Golden eagles and juvenile Bald eagles.