The Great Gray Owl (Strix nebulosa) and the Great Horned Owl (Bubo virginianus) are both large, impressive owls found in North America. Though they share some similarities, there are also many differences between these two species when it comes to their appearance, habitat, hunting behaviors, breeding patterns, and more.
Appearance
One of the most noticeable differences between the Great Gray Owl and the Great Horned Owl is their size. The Great Gray Owl is significantly larger, standing at around 28 inches tall with a wingspan around 60 inches. The Great Horned Owl is smaller in comparison, averaging 22 inches tall with a wingspan around 50 inches.
The plumage of these two owls is also quite distinct. The Great Gray Owl has beautiful, intricate grey and brown patterning across its body and wings. It has a very large, round facial disc with intricate concentric grey circles around the eyes. The overall look is refined and elegant.
Meanwhile, the Great Horned Owl has bolder plumage consisting of mottled brown, black, white, and grey. It has prominent ear tufts, adding to its unique and almost fierce appearance. The facial disc is less defined compared to the Great Gray.
When perched, the Great Gray Owl has a very slender profile with a long tail, giving it a larger than life appearance. The stockier Great Horned Owl has a squatter profile in comparison.
Size Comparison
| Owl Species | Height | Wingspan |
|---|---|---|
| Great Gray Owl | 28 inches | 60 inches |
| Great Horned Owl | 22 inches | 50 inches |
Habitat
The habitats frequented by the Great Gray Owl and Great Horned Owl also set them apart. The Great Gray Owl is found primarily in dense, old growth coniferous forests across Canada, Alaska, and the Pacific Northwest region of the United States. It relies on broken-topped trees and dense areas for nesting and roosting.
On the other hand, the Great Horned Owl occupies a wider range of wooded habitats across most of North and South America. These habitats include hardwood, coniferous, or mixed forests along with swamps, deserts, and vegetated urban areas. The Great Horned Owl is very adaptable to different environments.
Preferred Habitats
| Owl Species | Preferred Habitat |
|---|---|
| Great Gray Owl | Old growth coniferous forests |
| Great Horned Owl | Diverse wooded habitats including forests, swamps, deserts |
Hunting and Diet
As these two owl species frequent different habitats, their hunting strategies and diets also differ.
The Great Gray Owl is an opportunistic hunter, but favors small rodents like voles, pocket gophers, and mice. It relies on its amazing hearing to locate prey moving under the snow, and can plunge feet-first through deep snow to grasp rodents with its sharp talons. Its long wings allow it to maneuver with agility through dense forests when hunting.
The Great Horned Owl has a much more diverse diet, preying on a huge variety of small to medium sized animals. Common prey includes rabbits, hares, rats, mice, squirrels, oppossums, skunks, and reptiles. However, the Great Horned Owl occasionally hunts larger prey as well, including raptors like Peregrine Falcons. Unlike the Great Gray, the Great Horned is not adept at hunting through snow.
Differences in Hunting & Diet
| Owl Species | Hunting Adaptations | Common Prey |
|---|---|---|
| Great Gray Owl | Excellent hearing to locate rodents under snow, capable of diving into deep snow to capture prey | Voles, pocket gophers, mice |
| Great Horned Owl | Powerful talons and sharp beak for killing a variety of prey | Rabbits, hares, squirrels, skunks, rats, mice |
Breeding & Nesting
The breeding seasons and nesting preferences of the Great Gray Owl and Great Horned Owl also highlight their differences.
Great Gray Owls begin breeding in late winter. They rely on existing nests built by hawks, crows, squirrels, or other animals rather than building their own nests. Cavities in broken treetops are preferred nesting spots. Females lay just 2-3 eggs per season.
Great Horned Owls begin nesting much earlier, starting in late winter or early spring. They often take over an existing nest or may build their own in a high tree fork, rocky crevice, or abandoned building. Females lay 1-3 eggs. Great Horned Owls are known for their fierce defense of nests.
An interesting difference is that Great Gray Owls rarely use the same nest twice, while Great Horned Owls frequently re-use nesting sites across breeding seasons and even build upon existing structures year after year.
Breeding & Nesting Differences
| Owl Species | Breeding Season | Nest Preferences | Typical Clutch Size |
|---|---|---|---|
| Great Gray Owl | Late winter | Existing nests in broken treetops | 2-3 eggs |
| Great Horned Owl | Late winter or early spring | Tree forks, rocky crevices, abandoned buildings | 1-3 eggs |
Vocalizations
The calls of the Great Gray Owl and Great Horned Owl also provide stark contrasts between these two species.
Male Great Gray Owls perform a deep, rhythmic hooting during the breeding season. Females respond with a raspy barking call. The deep hoots carry well through dense, quiet forests. Great Gray Owls are mostly silent outside of the breeding season.
Great Horned Owls have a much wider repertoire of vocalizations. Their most recognizable call is a low, booming “hoo-hoo-hoo hoo” often transliterated as “Who’s awake? Me too.” They also make various screeches, screams, barks, and hisses depending on context. Great Horned Owls are quite vocal year-round.
The calls of both owls serve to establish territories and attract mates. The Great Horned Owl has more complex vocal communication compared to the Great Gray.
Conservation Status
When it comes to conservation status, the Great Gray Owl is more vulnerable as a species than the thriving Great Horned Owl.
Great Gray Owl populations are sparse and isolated across their range, existing at naturally low densities and relying on specific forest habitats. Habitat loss is the biggest threat they face along with human disturbance, particularly during the breeding season. The species is listed as Endangered in Canada.
On the other hand, Great Horned Owls are abundant and quite adaptable to living alongside human activity. They are common across most of their wide range through the Americas. Populations are currently stable and the species is classified as Least Concern.
| Owl Species | Conservation Status |
|---|---|
| Great Gray Owl | Vulnerable, Endangered in Canada |
| Great Horned Owl | Least Concern, thriving population |
Conclusion
In summary, while the Great Gray Owl and Great Horned Owl share some common traits as large, predatory owl species, they have many distinct differences when it comes to appearance, habitat preferences, hunting behaviors, breeding biology, vocals, and conservation status.
Understanding these variations is important for effective identification, management, and appreciation of both species in the regions where they reside. Their unique traits and adaptations showcase the amazing biodiversity within the owl family.
