Golden Eagles are among the largest birds in North America, with a length ranging from 27.6 to 33.1 inches (70-84 cm), a wingspan of 72.8 to 86.6 inches (185-220 cm), and a weight of 105.8 to 216.1 ounces (3000-6125 g). Their wings are broad, similar to a Red-tailed Hawk’s, but longer. At a distance, the head appears relatively small, and the tail projects farther behind than the head does in front.
Variations in Size Between Subspecies
Golden Eagles exhibit significant variations in size between different subspecies. The largest subspecies, A. c. daphanea, has males that typically weigh 4.05 kg (8.9 lb) and females that weigh 6.35 kg (14.0 lb). In contrast, the smallest subspecies, A. c. japonica, has males that weigh 2.5 kg (5.5 lb) and females that weigh 3.25 kg (7.2 lb).
| Subspecies | Male Weight | Female Weight |
|---|---|---|
| A. c. daphanea | 4.05 kg (8.9 lb) | 6.35 kg (14.0 lb) |
| A. c. japonica | 2.5 kg (5.5 lb) | 3.25 kg (7.2 lb) |
Sexual Dimorphism in Size
Females are generally larger and heavier than males, with the difference being more pronounced in larger subspecies. For instance, in the Himalayan golden eagles, females are about 37% heavier than males and have nearly 9% longer wings. In the smaller Japanese golden eagles, females are only 26% heavier with around 6% longer wings.
Record-Breaking Sizes
The maximum size of golden eagles is debated, with some sources suggesting a wild female from the A. c. chrysaetos subspecies weighed around 6.7 kg (15 lb) and had a wingspan of 2.55 m (8 ft 4 in). However, a massive female golden eagle from Wyoming’s Bridger-Teton National Forest weighed 7.7 kg (17 lb), making it the heaviest authenticated wild female.
Comparison to Other Eagle Species
Golden Eagles are known to have a wingspan that is the fifth largest among living eagle species. This places them behind the Steller’s Sea Eagle, the Philippine Eagle, the Wedge-tailed Eagle, and the White-tailed Eagle in terms of wingspan.
Factors Affecting Size
The size of golden eagles can be influenced by various factors, such as geographic location, habitat, and food availability. Larger subspecies tend to be found in colder, mountainous regions, where they have access to larger prey, while smaller subspecies are typically found in warmer, more temperate areas.
Conclusion
In summary, Golden Eagles are impressive birds of prey, with significant variations in size between different subspecies. Females are generally larger and heavier than males, and the largest authenticated wild female weighed an impressive 7.7 kg (17 lb). Understanding the size and characteristics of these magnificent birds is crucial for their conservation and appreciation.
References:
– Golden Eagle Identification, All About Birds, Cornell Lab of Ornithology, https://www.allaboutbirds.org/guide/Golden_Eagle/id
– Golden eagle, Wikipedia, https://en.wikipedia.org/wiki/Golden_eagle
– Golden Eagle | Audubon Field Guide, https://www.audubon.org/field-guide/bird/golden-eagle
