A giant owl in Russia may be helping conservationists. How? The world's largest owl may be a key indicator for the health of some of the last primary forests of Russia's Far East.

The owl, known as Blakiston's fish owl, is a sub-group of eagle owl that specializes in hunting near rivers and feeds mainly on fish. With a wingspan that can reach more than six feet in length, this owl is impressive to see. Yet these owls are picky when they choose where to live. They prefer old-growth forests along streams--for a good reason. When these massive trees die, then fall over and disrupt water flow. This forces the gushing river around obstacles, forming a complex stream channel that includes a combination of deep, slow-moving backwaters and shallow, fast-moving channels. This, in turn, provides perfect habitat for salmon and other fish.

In order to examine these owls a bit more closely, the researchers looked at the foraging and nesting behavior of Blakiston's fish owl in Russia. There, they looked a nesting habitat over 7,804 square miles. They found that large old trees and riparian old-growth forest were the primary distinguishing characteristics of both nest and foraging sites.

Because this owl prefers this type of habitat, the management and conservation of old-growth forests is essential for preserving this species. Yet it's not only this owl that calls these forests home. There are also eight salmon and trout species, 12 other owl species and mammals like the endangered Amur tiger, Asiatic black bear and wild boar. This protection, though, goes both ways.

"Blakiston's fish owl is a clear indicator of the health of the forests, rivers and salmon populations," said Jonathan Slaght, lead author of the new study, in a news release. "Retention of habitat for fish owls will also maintain habitat for many other species associated with riparian old-growth forests in the Russian Far East."

The findings are important for conserving this type of habitat. The owl could potentially be used as an indicator species in order to assess exactly how the ecosystem is faring. This could be crucial for future efforts.

The findings are published in the journal Oryx.