Which species of owl is the largest on earth with the longest recorded wingspan?

Blakiston's Fish Owl is the world’s largest species of owl. A recent field study of this species shows a male with a weight of 3 to 3.75 kg (6.6 to 8.3 lbs), with females up to 4.5 kg (10 lbs), to around 25% larger. With a body the size of a small child and a wingspan of up to two meters, the Blakiston's fish owl (Bubo blakistoni), on average, takes the title for "owl with the greatest wingspan". They're found in Siberia, northeast China and in Japan, on the island of Hokkaido. It is also one of the rarest, shiest and least studied.

Although it is North America's largest owl with a wingspan up to 60 inches, the great gray owl is mostly fluff, weighing only 2-3 pounds, about half the weight of a snowy owl.

Also, although 9 cm (3.5 in) shorter than the largest of Its species, the Eurasian eagle-owl can weigh well more than twice as much as the largest great grey owl. It typically has a wingspan of 131–188 cm (4 ft 4 in–6 ft 2 in).