Golden Eagle (Aquila chrysaetos) Fact Sheet: Physical Characteristics

Body measurements

(Brown & Amadon 1968; Edwards & Kochert 1986; Johnsgard 1990; Thiollay 1994; Watson 1997; Bedrosian et al. 2008)

• A large, dark brown raptor often seen flying with wings held in a shallow "V" with outer primary feathers spread
• Pale yellow or tawny plumes on the back of the head give the species its name
• Feathered legs (tarsi) and a wing length of at least 550 mm are a defining feature of this raptor (Johnsgard 1990)

(Brown & Amadon 1968; Edwards & Kochert 1986; Johnsgard 1990; Thiollay 1994; Watson 1997; Bedrosian et al. 2008)

Female is larger - "reverse sexual dimorphism" (Bedrosian et al. 2008)

• Females often 40% heavier than males (Edwards & Kochert 1986)
• Female wing length up to 10% greater than male's (Watson 1997)
• Degree of overall dimorphism moderate compared to other raptors (Brown & Amadon 1968)
• An exceptionally large female captured in Wyoming weighed 7,200 g (about 16 lb) (Bedrosian et al. 2008)

(Brown & Amadon 1968; Edwards & Kochert 1986; Johnsgard 1990; Thiollay 1994; Watson 1997; Bedrosian et al. 2008)

Plumage and molting

• As one of the "booted" eagles, feathers extend down the legs (tarsi) to the feet
• Adult plumage dark brown except for golden rear crown, throat and sides of neck
• Gray bars on tail
• Juvenile plumage (first year) darker, with white at base of secondaries and primaries; base of tail white with dark terminal band
• Adult plumage by 5th summer
• Molting begins in April, peaking by July or August; lasts more than one year (Watson 1997)
• Feet yellow 
• Iris yellow or hazel to dark brown
• Bill black to bluish slate-black
• Distinguished from immature bald eagle by: (Clark & Wheeler 1987) (Watson 1997)
• White restricted to base of flight feathers; bald eagle - scattered white feathers
• Bald eagle has no feathers on legs
• Similar looking species: (Cornell Ornithology Lab 2011)
• Immature Bald Eagle - wings flat when soaring; legs bare; white scattered over body and wings
• Turkey Vulture - wings held up and may tilt sideways, back and forth when soaring; no white spots on top of wings
• Immature California Condor - larger with white wing linings but no white on flight feathers

Image credit: © San Diego Zoo Wildlife Alliance. All rights reserved.