Both the bald eagle and the golden eagle are large birds of prey native to North America. The bald eagle is the national symbol of the United States, while the golden eagle is widespread across the continent. There are some key physical differences between these two eagle species when it comes to their size.
Quick Answer
The golden eagle is larger than the bald eagle. On average, golden eagles are both longer and heavier than bald eagles, with a greater wingspan as well.
Bald Eagle Size
The bald eagle is a large bird, but is on the smaller end of the eagle size spectrum. Here are some key size statistics for the bald eagle:
- Length (head to tail): 70–102 cm (28–40 in)
- Wingspan: 168–244 cm (5.5–8 ft)
- Weight: 3–6.3 kg (6.6–14 lb)
The female bald eagle is larger than the male, with an average weight of 5.8 kg compared to 4.1 kg for males.
Length
Bald eagles measure 70–102 cm in length from head to tail. This makes them on the smaller end for eagles, with several species surpassing them in length. The bald eagle’s long, broad wings and short tail contribute to a smaller body length compared to other eagles.
Wingspan
With a wingspan of 168–244 cm, the bald eagle has broad, wide wings. The wingspan allows it to soar and glide with ease and maneuver well in flight. Large wings provide lift for carrying prey items back to the nest.
Weight
Weighing 3–6.3 kg, the bald eagle is on the lighter end of eagle sizes. Females, which are larger, weigh an average of 5.8 kg, while males average just 4.1 kg. Their lighter weight allows them to get lift and fly without too much exertion.
Golden Eagle Size
The golden eagle is North America’s largest eagle species. They surpass bald eagles in length, wingspan, and weight. Here are the key size statistics for golden eagles:
- Length: 66–84 cm (26–33 in)
- Wingspan: 185–220 cm (6.1–7.2 ft)
- Weight: 3–6.3 kg (6.6–14 lb)
Like bald eagles, female golden eagles are larger, weighing on average 4.05 kg vs. 3.25 kg in males.
Length
Golden eagles measure 66–84 cm long from head to tail. This makes them marginally longer on average than bald eagles. Their extra length comes from subtle differences in body shape and tail length.
Wingspan
With a wingspan range of 1.85–2.2 m, golden eagles have a broader wingspan than bald eagles. Their wings are not quite as broad in proportion to their bodies, but are longer tip to tip.
Weight
Golden eagles are on average slightly heavier than bald eagles. Males weigh around 3.25 kg compared to 4.05 kg for females. This is heavier than bald eagles, though the two species overlap considerably in mass.
Comparing Bald Eagle vs. Golden Eagle Size
When compared directly, the size differences between bald eagles and golden eagles become clear:
| Measurement | Bald Eagle | Golden Eagle |
|---|---|---|
| Length | 70–102 cm | 66–84 cm |
| Wingspan | 168–244 cm | 185–220 cm |
| Weight | 3–6.3 kg | 3–6.3 kg |
Key Differences:
- Golden eagles have a longer average body length than bald eagles.
- Golden eagles have a wider wingspan on average.
- Golden eagles tend to be marginally heavier than bald eagles.
- Female golden eagles are the heaviest, while male bald eagles are the lightest on average.
The size differences show that the golden eagle is indeed larger overall than the bald eagle. However, there is considerable overlap, and large bald eagles may exceed small golden eagles in some metrics.
Why the Size Difference?
Several factors contribute to the golden eagle’s larger size compared to the bald eagle:
Species Adaptations
The golden eagle occupies a wider range of habitats and elevations than the bald eagle. It is found in mountainous, open country where it relies more on thermal soaring and gliding flight. Its larger wingspan provides greater lift and control in these environments. Bald eagles mainly occupy coastal areas and inland waterways where less open flight is required.
Prey Size
Golden eagles regularly attack larger prey than bald eagles. Their diet includes jackrabbits and other large mammals, whereas bald eagles feed mostly on fish and water birds. Taking down bigger prey requires greater size and strength.
Competition
There may be less competition pressure on golden eagles driving them towards smaller size. Bald eagles overlap in range with many fish-eating birds that compete for the same food resources. Staying smaller reduces competition.
Sexual Size Dimorphism
The tendency for female raptors to be larger than males is more pronounced in golden eagles than bald eagles. This increases the average size difference between the species.
Conclusion
In summary, the golden eagle is indeed marginally larger than the bald eagle when comparing average length, wingspan, and weight. However, there is significant overlap in size, meaning some individual bald eagles may exceed certain golden eagles in these measurements. Factors like species adaptations, prey size, competition, and sexual size dimorphism contribute to the golden eagle’s larger average size. So while the bald eagle beats out the golden eagle as the national symbol of the United States, the golden eagle claims the title of the larger of these two magnificent North American eagle species.
