Status Least Concern
Size Height: 57–67cm
Weight Male 568–1110g; female 977–1900g
Gestation 28-36 days
Young 2-9 eggs are laid
Life span Up to 27 years
Great grey owls mainly eat small mammals, especially rodents. They also eat small birds and occasionally frogs and large insects. These owls swallow smaller prey whole, and pull larger prey to pieces first.
Great grey owls are found in many countries in the northern hemisphere, including the US, Canada, China, northern Europe and Russia. They live in a variety of forested habitats, including boreal and coniferous, preferring areas that have breaks in the forest, such as bogs, open fields, and meadows. They mainly forage at the edge of the forests or in open areas.
Great grey owls lay their eggs in a variety of makeshift nests, such as the abandoned nests of other birds of prey, the forks of large branches, mistletoe, and even shallow depressions at the base of trees or artificial nest platforms. They may nest up to 30 metres off the ground. Females incubate the eggs, and the males come to the nest to feed her. The female will only leave the nest to defecate and to regurgitate pellets. The young leave the nest at 25 to 30 days of age, when they are still unable to fly. Instead, they will climb leaning trees to roost off the ground until they are able to fly a week to two weeks later. These owls usually start to breed at three years of age.
Little is known about the predators of these birds, but nesting great grey owls are known to attack black bears and drive off northern goshawks that enter the nest area, suggesting that these species are predators of the young.
This species does not currently face any major threats, and its population size is thought to be increasing. However, great grey owls may face a number of threats in some places, including from hunting, loss of habitat and collisions with traffic, power lines and cables.
Great grey owls hunt from their perch. They listen carefully and watch the ground, then when they detect their prey they fly up to 100m to strike it.
The abundance of food within the habitat of the great grey owl can have an effect on the number of eggs they lay.
These owls have such excellent hearing that they can hear their prey underneath the snow. They will plummet into the snow with their feet clenched. They can break though a crust of snow that is hard enough to support an 80kg weight, and as deep as 45cm!
We visited Marwell Zoo for the day with a large group of our sheltered housing residents from Portsmouth. It was a super day which all the residents enjoyed. There was something for everyone and a favourite animal for everyone! Residents felt there was so much to see, and lovely facilities on… Read full reviewRachael, 8th September 2017