Great grey owl

The great grey owl is the longest owl in the world, measuring about 61 to 84 centimetres from beak to tail. It has a big round head, gray feathers with pale bars, small yellow eyes ringed with dark circles, and the largest facial disc of any bird of prey.

It lives in the cold northern forests of North America and Eurasia. It looks enormous, but much of its size is fluffy feathers, a big head and a long tail. Under all that fluff its body is lighter than many other large owls. It is the only owl of its genus, Strix, found in both the Eastern and Western Hemispheres, and the common name comes from its grey colour.

How does it hunt?

The great grey owl mostly eats small mammals such as voles. Its large facial disc works like a satellite dish and gathers sound towards its ears. It can hear a vole moving under deep snow.

When it has pinpointed the sound, the owl drops down and plunges into the snow with its feet to grab the prey. The young may chatter, shriek or hiss, while adults are normally quiet.

How big is it, really?

A female averages about 72 centimetres long and a male about 67 centimetres, and the wingspan averages around 140 centimetres. Weight ranges from roughly 580 grams to 1.9 kilograms, with an average of about one kilogram for males.

So although it beats the Eurasian eagle-owl in length, several other owls are heavier. The call is a series of very deep, slow hoots, given mostly around its territory. Two subspecies are known: one in North America and one from Scandinavia across Siberia to Sakhalin.

On the globe

The globe places the great grey owl in the Siberian taiga forest. Look for the big round face with small yellow eyes.