Great grey owls are large owls that have a mostly grey plumage. They have two concentric circles of darker plumage surrounding their facial disk. This disc is very flat and helps direct sounds into their asymmetric ears, meaning that they have excellent hearing. They have very soft feathers, which enables almost silent flight making them exceptional hunters.
These owls inhabit coniferous forest in the northern hemisphere. They hunt for prey during both the night and day due to their excellent hearing and vision.
Great grey owls breed between March and June, depending on snow cover. Males will perform aerial displays and bring gifts of food back to the female to entice her to mate. Whether these owls breed and the success of breeding is heavily dependent on food availability. If food sources are low they may not breed at all. Both the male and the female will bring food back to the owlets, tearing it into smaller pieces so it is easier for them to eat. Owlets fledge at around four weeks of age.
The diet of these owls consists mainly of small rodents, such as voles and pocket gophers. They can hear prey even when there is a heavy snow covering.
Great grey owls are currently classed as Least Concern. The biggest threat facing great grey owls is habitat destruction. Timber harvesting reduces trees suitable for nesting, reducing the breeding success of this species in those areas. Continued expansion of timber harvesting could be a major threat in the future.