Bald Eagle (Haliaeetus leucocephalus)
Prepared by Paul Nicholson, London Bird Team, November 2022
The Bald Eagle is named for the white plumage of the mature bird’s head. The first part of the Latin binomial name identifies the bird as an eagle and the second part, leucocephalus, translates to “white-headed.” All photos by Paul Nicholson.
By any measure, Bald Eagles are big, powerful birds. Of the species seen each year across London and Middlesex County, only the Trumpeter Swan’s wingspan matches the 203 cm wingspan of the Bald Eagle. The adult Bald Eagle has dramatic plumage with a dark body and wings and a contrasting white tail and head. Its beak is massive.
It takes five years for the birds to attain their iconic look. A younger bird is mostly dark with some white splotchiness and a dark beak. Because of this plumage, sub-adult Bald Eagles are sometimes confused with Golden Eagles. (In a late 2021 Bird Friendly London blog post, Laure Neish describes the differences.)
This is a juvenile Bald Eagle. The size and shape of the bird are the same as the adult but the field marks are different and sometimes confusing.
Bald Eagles will nest anywhere between February and June. The incubation period is five weeks. Eagles in Southwestern Ontario will often build a nest high in a deciduous tree, close to the trunk so that the large structure can be well-supported. Nests are usually two metres across and a metre or so in depth. The weight of nests varies but 500 kg nests are normal. Nests are frequently reused year after year.
Bald Eagle nests are massive. The bird on the top of this nest gives you a sense of scale. The largest on record was a nest in Florida that weighed 2,000 kg and was used for 34 years.
The main part of the Bald Eagle’s diet is fish. It is therefore unsurprising to see one cruising along the Thames River or soaring near Fanshawe Lake. These birds will also eat other food such as waterfowl, mammals, reptiles, amphibians, and crabs.
Bald Eagles can be found across North America. Many will migrate south from Ontario for the winter, but some will stay in Middlesex County through the winter months.
We can continue to learn conservation lessons from the Bald Eagle. Bald Eagles were among the species hit hardest by DDT. The insecticide was used widely across the agricultural sector through the middle of the 20th century and because it caused thinning of egg shells, birds’ breeding success plummeted. Rachel Carson’s 1962 book Silent Spring brought attention to the perils of the indiscriminate use of pesticides. By the 1970s, the U.S. and Canada had banned DDT. Other factors contributing to the decline of the Bald Eagle were addressed. Although the North American Bald Eagle population did rebound following the DDT ban, it is still a species at risk in Ontario. Its status is Special Concern, meaning that “it may become threatened or endangered due to a combination of biological characteristics and identified threats.”
The Bald Eagle’s vocalization is surprising given the bird’s imposing stature. It issues a high-pitched peeping call.
Listen to the Bald Eagle’s vocalization below:
Bald Eagles in flight can be identified by their size and flight style. When soaring, their wings are plank-straight. These birds may fly hundreds of miles each day. The bird pictured here is a sub-adult Eagle.
Not surprisingly, Bald Eagles have been adopted as powerful symbols across many cultures. I reached out recently to Shadia Ali, the Communications Officer for the Chippewas of the Thames First Nation south-west of London. “Eagles are very important to First Nations peoples and have a sacred place in our daily lives and ceremonies. Eagles are very spiritual as they fly closest to Creator. Seeing an eagle is considered a sacred blessing. Eagle feathers are given as gifts of honour in ceremonies and the feathers are considered very special. Eagle feathers must be earned.” The Ojibwe word for Bald Eagle is migizi.
The Bald Eagle is the official bird of the United States. A stylized Eagle is depicted on the official seal of the President.
Help make London more Bald Eagle friendly:
Advocate for the preservation of natural areas that provide habitat for Bald Eagles.
Don’t leave fishing line by rivers and ponds. If you find some, consider collecting and disposing of it. Bald Eagles often hunt near water and are prone to becoming tangled.
Do not use rodenticide / rat poison at work or at home. Rodenticide compounds will biomagnify and cause secondary poisoning in raptors like Bald Eagles. In fact, a recent study found over 80% of Bald Eagles tested in the United States had rodenticide in their blood. Adopt other humane methods for pest control instead. Learn more
If you hunt, please do not use lead ammunition. Lead accumulates in the tissues of animals that Bald Eagles eat, and can cause heavy metal poisoning. Learn more
Do not throw food out the window of moving vehicles, and remember to check the back of pickup trucks before driving. Food and garbage draws prey animals like rodents to roads, which in turn attract birds of prey like Bald Eagles that are put at risk of being hit by passing vehicles.
Avoid use of pesticides and reduce your ecological footprint as much as possible.
Participate in citizen science initiatives such as recording Bald Eagles and other bird sightings in eBird or using iNaturalist.