The Eurasian eagle-owl is one of the largest owls in the world, and a Los Angeles Zoo page says it is the world's heaviest owl. Animal Diversity Web lists adult mass as 1,600 to 4,200 grams, length as 58 to 71 centimeters and wingspan as 1.5 to 2 meters. Its size tends to shrink from north to south and from east to west. It forms a superspecies with the Great Horned Owl and the Rock, Pharaoh and Cape eagle-owls, and the borders between these species are not clear.

An eagle-owl uses keen eyesight and hearing to find prey at night, and its wing feathers are shaped to make little noise. Eagle-owls eat many kinds of animals, from beetles to fawns, and they also eat birds, reptiles, amphibians and fish. A pellet study in southeastern France found that the pellets showed a broad dietary range, which reflects the generalist predator behaviour of the Eagle Owl. Scientists think habitat choice and nesting success depend mainly on having enough of certain prey, such as European rabbits.

Eagle-owls are elusive, which makes them difficult to study in their natural habitats. Owl pellets help scientists understand what these hard-to-find birds eat. Animal Diversity Web gives a territory size range of 15 to 80 square kilometers, with an average of 42.5. Home ranges of Eurasian eagle-owls vary in size with habitat structure and composition, the owl's sex and its state of health. In south-eastern Spain, researchers monitored 72 Eurasian eagle-owl territories between 2006 and 2012. A researcher counts a successful pair as one that raised at least one young until it was 50 to 60 days old.

In Europe, the Eurasian eagle-owl's numbers fell in the first half of the 1900s. As of November 2026, the Peregrine Fund says they are recovering but have not returned to what they were before the mid-1900s. A zoo raptor group fact sheet cites a 1999 estimate that the wild European population may number about 25,000 pairs. As of November 2026, the IUCN Red List lists the Eurasian eagle-owl as Least Concern. Reintroduction programs have been run in Germany, France, Belgium, Switzerland and Scandinavia, and have faced high mortality and low reproductive success.

Eagle-owls do not build a nest. They use ledges, caves, and the old nests of other large birds. The female sits on the eggs for a little over a month, up to about 36 days. Chicks grow quickly: they feed themselves at three weeks and fly short distances by about 52 days. A zoo raptor group says eagle-owl young are independent at 150 to 160 days of age. Young usually stay in their parents' territory for another 3 to 4 months before looking for a territory of their own.

Words to know

• generalist: eats many kinds
• elusive: hard to find
• territory: an animal's area
• pellets: coughed-up balls