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Wildlife of the Week!
This Wildlife of the Week we highlight one of the most recognizable birds of the Salish Sea and beyond. The bald eagle (Haliaeetus leucocephalus) is one of the largest birds in North America and is the largest bird of prey in Canada. The bald eagle, once in its familiar adult plumage, is known to many. Sometimes when the bird is a juvenile, it is confused for an adult golden eagle (Aquila chrysaetos). The bald eagle is a significant member of the Salish Sea community, and other ecosystems around North America. To learn more about this important bird, read on below!
In terms of overall bird sizes, the bald eagle ranks as “goose-sized or larger” (TheCornellLab, see below). This is proven through the bald eagle’s maximum weight of 6.5-14 pounds and a possible wingspan of up to eight feet wide! Females are larger than males, and geographical location can also play a role in body size (northern individuals are often bigger than southern ones). As an adult, the bald eagle’s plumage is distinct- it has a dark, brown body and a white head and tail. The large hooked bill, talons and legs are bright yellow. These sharp talons are equipped with spiky projections called “spicules”. As a juvenile, bald eagles will remain mottled dark brown and white before gaining the adult plumage at 4-5 years old.
Bald eagles are very common throughout Canada (highest numbers along B.C.’s coast), as well as in Alaska. They can also be found in other regions of the U.S. and northern Mexico. They are an eagle that is only found in North America, and the only eagle exclusive to this continent. Bald eagles favour regions near water sources due to prey accessibility, which may include fresh or salt water habitats. Bald eagles can be spotted within forests, near coasts, marshes, lakes, reservoirs, rivers, marshes and even around human facilities such as dumpsters and fish-processing sites. They may migrate or not, this is often dependent on whether their fishing sites freeze over in the wintertime.
The bald eagle is a versatile and non-picky eater; it may hunt, fish or scavenge meals. These eagles are a top predator, and they can exercise this position by catching mammals or hunting gulls and waterfowl. They are also extremely efficient fishers. The bald eagle, instead of always hunting for food, usually finds other tactics to feed. It will often force its access to prey killed by other animals, eat carrion (e.g. roadkill) or scavenge garbage. Its sharp, articulated talons aid in prey capture when the bald eagle does go in for a live hunt. Adults are more experienced and likely to hunt actively, whereas younger individuals may resort to easier tactics. Active hunting may be done from a tree or other perch, when flying in the sky, when on the ground or in shallow water.
The bald eagle is believed to have a strong tendency to mate for life, although certain circumstances may change this behaviour (e.g. lack of breeding success, death or disappearance of a mate). Courtship rituals between the pair are extensive and involve both vocal and flying displays performed together. Bald eagles will create one of the world’s largest nests, mostly with twigs, vegetation and feathers. These nests will often be seen in large, tall trees (especially those of old growth), and the pair will defend a significant area around the nest (about 1-2km). This eagle may also nest on cliffs, rocky points, on the ground (tundra) or on man made structures, depending on habitat and available habitat structures.
The timing of egg-laying is dependent on where the eagles live in the continent, with northern birds breeding later. The female will lay between 1 and 3 eggs and will usually be the one to incubate the eggs until hatching and shield the young nestlings, while the male delivers food to the nest. Food delivery will be done by both parents as the chicks age, and the young will become independent (from time of egg-laying) at about 16-18 weeks.
The bald eagle is an extremely important aspect of many Indigenous Peoples’ cultures. Depending on the culture, the bald eagle could be traditionally used for sustenance, rituals, decoration of clothing and material making (e.g. for snares and arrows). For example, the Nuxalk, Nootka and Vanta Kutchin Peoples placed eagle feathers on the tips of their arrows to assist in hunting. Coast Salish Peoples revered the bald eagle; its spirit was sought out by young men and its down was important for hunting rituals. The significance and uses of the bald eagle are vast and diverse to various groups of Indigenous Peoples; see here for more information.
Today, the bald eagle faces threats in this industrious and rapidly changing world. Some populations in Canada and the United States are endangered or extirpated; despite this, it is still considered to be fairly common throughout its range. The bald eagle faced considerable declines upon arrival of European settlement through habitat loss, competition and shooting and trapping by humans. In 1940, the population seemed to increase due to tougher legislation, however bald eagles faced another challenge attributed to pollution through DDT. DDT is a pesticide that was used to control salt marsh mosquitoes on the gulf coast, but impacted predatory birds on an astronomical scale by reducing their ability to lay eggs with strong shells. The banning of DDT in 1972 appeared to help with bald eagle recovery, but they were almost eliminated from the U.S. completely due to the factors above. Fortunately today, bald eagles have been reported nesting in over half of U.S. states.
Several methods such as rehabilitation, sanctuaries and reintroduction have helped the population in its various ranges, yet it is important to remember that the bald eagle faces many challenges to reach adulthood. Human interference through habitat destruction, heavy metal concentrations, disturbance, power lines and pollution to food sources can still cause significant impairment to bald eagle reproduction and/or survival anywhere.
It will be important for us to continue and even improve conservation measures for this bird and its future.
When spotting a bald eagle, you are most likely to see it alone, however you may spot a large group if lots of food is available. Remember to always respect wild animals and their habitats!
Would you like to test your knowledge of this amazing bird? Try out some trivia below!
- True or False? The bald eagle is a type of raptor. (ANS: True).
- Males and female birds have _____ plumage (different, the same, almost the same). (ANS: The same).
- Bald eagles see ____ than humans (worse, better, the same). (ANS: Better- 3-4 times better)!
BONUS CHALLENGE:
How many species of eagles are in the world?
59!
Article Authored By: Alexa D., B.Sc./ Five Star Whale Watching.
To learn more about the eagle’s history, cultural significance and more, check out our References below!
Centre for Indigenous Peoples’ Nutrition and Environment and McGill University.
