Species Guide: Bald Eagle (Haliaeetus leucocephalus)
Family: Accipitridae
The Bald Eagle (Haliaeetus leucocephalus) is a large North American raptor renowned as the national symbol of the United States. Its common name derives from an Old English word “balde” meaning white, highlighting the vivid white head and tail of adult birds. Bald Eagles are closely linked to rivers, lakes, and coastal habitats where fish, their chief prey, are plentiful.
Appearance
Adult (Male and Female)
Adults display dark brown bodies and wings, a striking white head and tail, and a large, hooked yellow bill. Male and female plumage is similar; females are noticeably larger (see Biometrics). Plumage becomes definitive at about 4–5 years when the full white head and tail develop.
Male
Males are smaller than females but otherwise identical in adult plumage. Their reduced size grants males greater speed and agility in certain hunting situations, though roles vary by pair and prey type.
Female
Females are larger and heavier, a common trait in birds of prey called reverse sexual size dimorphism. The larger females often take the lead role in incubating eggs and defending the nest.
Juveniles / Immatures
Juveniles leave the nest mostly dark brown with variable mottling on their body and wings. Their bill and bare parts (legs/feet) are darker at first and gradually turn yellow with maturity. Full adult plumage develops gradually over ~4–5 years, passing through several intermediate plumages.
Diet
Bald Eagles are opportunistic carnivores with a strong preference for fish (trout, salmon, catfish, etc.). They hunt by soaring and swooping to snatch fish from the water with their talons, but they also take birds (including waterfowl), small mammals, and carrion. Juveniles and inexperienced birds often scavenge more than adults. Bald eagles sometimes steal (kleptoparasitize) prey from ospreys and other raptors.
Habitat
Bald Eagles are associated with aquatic habitats, coastlines, rivers, large lakes, and marshes, where fish and waterfowl concentrate. They require tall trees or cliffs for nesting and roosting, and their distribution spans most of Canada and the United States, with Alaska holding some of the largest populations. In winter, many birds move to areas with open water.
Resident
Summer
Passage
Winter
Star = Spurious Records
Behavior
Behavior and Hunting
Bald Eagles are powerful fliers, using thermal updrafts and large wing area to soar and search for prey. They commonly perch near water and launch short, powerful flights to capture prey. They are social around rich food sources (e.g., salmon runs, carrion) and may be seen in loose congregations during non-breeding seasons.
Call
The stereotypical “bald eagle call” is a high-pitched, whistling or chirping series rather than the deep, resonant caws movie soundtracks sometimes use. The song can be a sequence of short whistles, chirps, and piping notes used in courtship, communication, and alarm.
Bald Eagle Call:
Betchkal, Davyd, xeno-canto.org
Life cycle and reproduction
Bald Eagles form long-term pair bonds and often return to the same nest year after year, enlarging a stick nest (often called an “aerie”) that can become enormous over decades. Courtship includes spectacular aerial displays (locking talons and cartwheels). Females typically lay 1–3 eggs per clutch; incubation lasts about 35 days, with both parents involved. Young fledge at roughly 10–12 weeks but may remain near the nest learning to hunt for several months. Lifespans in the wild commonly exceed 20 years; some individuals have lived into their 30s.
Biometrics
| Wing Length | 71-96 cm |
| Wing Span | 1.8-2.3 m |
| Body Weight | 3-6.3 kg |
| Longevity | 20-30 Years |
Natural Predators
Adult Bald Eagles have few natural predators due to their size; threats to adults are mostly human-related or accidental (collisions, electrocutions). Eggs and nestlings are vulnerable to raccoons, ravens, great horned owls, coyotes, and occasionally large gulls or mammals that can reach nests. Aggressive nest defense by adults reduces many risks, but nest predation and brood loss do occur.
Relationship to Humans (including fables)
Bald eagles have long held cultural and symbolic importance:
- Symbolism: Adopted as a U.S. emblem in 1782, the bald eagle symbolizes strength, freedom, and resilience. It appears on the Great Seal and many federal emblems.
- Indigenous significance: Many Indigenous peoples of North America revere the bald eagle; eagle feathers have deep spiritual and ceremonial significance and are treated with strict cultural protocols.
- Fables and folklore: In folklore and popular culture, the eagle often stands for nobility, victory, and divine connection. Tales vary regionally, from stories of the eagle’s vigilance and regal bearing to cautionary fables about pride.
- Human conflict and co-existence: Historically persecuted (shooting, egg collection) and affected by contaminants, bald eagles are also beneficiaries of targeted conservation, nest protections, breeding programs, and public education have all helped recovery.
Conservation Status
Global / IUCN: The species is currently listed as Least Concern on the IUCN Red List due to a large range and overall numbers.
United States (federal): Following severe declines in the mid-20th century (largely from DDT and habitat loss), the Bald Eagle was listed under the U.S. Endangered Species Act. The population recovered substantially after DDT was banned (1972 in the U.S.) and through active conservation measures. The U.S. Fish & Wildlife Service removed the bald eagle from the federal endangered species list in August 2007, though protections remain under the Bald and Golden Eagle Protection Act and the Migratory Bird Treaty Act. Conservation and monitoring continue at federal and state levels.
Current trends and threats
Overall numbers have increased dramatically since the 1970s and remain stable or growing in many regions, making the species one of the more notable conservation successes in North America. Nonetheless, local populations can still be threatened by habitat loss, lead poisoning (from spent ammunition consumed in carrion), collisions with vehicles and power lines, illegal shooting, and localized contamination events. In some jurisdictions (e.g., certain U.S. states), eagles may retain state-level threatened or endangered status until local recovery is demonstrable.
Global
Conservation Status
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- By Mad Max, CC BY-SA 3.0, [Accessed 13/10/2025] ↩︎
References
Lovette, I. et al. (2016) The Cornell Lab of Ornithology, handbook of bird biology. Third edition. Chichester: Wiley. [Accessed 14/10/2025]
