The biggest owl in the world is the Blakiston's fish owl or Bubo blakistoni, found in eastern Russia and some Asian countries, such as China and Japan. The biggest owl in North America, on the other hand, is the great grey owl.Know More
The Blakiston's fish owl can be as heavy as 10 pounds. The wingspan can stretch as far as 6 feet, and they reach about 27 inches in length. In comparison, a great grey owl is longer, as it can reach 32 inches, but much lighter, as they only reach about 2 1/2 pounds (less in weight than other North America owls). The Blakiston's fish owl is endangered, mostly due to human influence, as they are accidentally shot or ensnared in traps.