Eurasian Eagle-owl

Quick Take

• This apex predator has zero natural enemies as an adult, and yet its population is still shrinking. Threats despite no predators →
• The feathery disc on its face is not merely decorative. It is a precision instrument that changes how the owl hunts. Facial disc explained →
• In captivity, these owls can live three times longer than in the wild, a gap that says everything about what's really threatening them. Wild vs. captive lifespan →
• It rules the skies across 12 million square miles, yet it isn't even the largest owl alive. Vast range explored →

Eurasian Eagle-owls, Bubo bubo, are the type species of the Bubo genus of horned owls. They are one of more than a dozen owl species with the words “eagle-owl” in their name. They are large, beautiful birds with broad, curved wings that can reach a span of more than 6 feet. Their enormous orange eyes are mesmerizing and vary in shade depending on the subspecies.

Found mainly in Europe and across Asia all the way to Japan and south to northern Africa, these owls range over more than 12 million square miles. They prefer rocky habitats near wooded areas at elevations from sea level to the high slopes of the Alps and the Himalayas, and make themselves at home in climates from the icy taiga to the edge of the desert. They are apex predators across their vast range, eating everything from rodents and lizards to small deer and antelope. Their only significant threat is humans.

Incredible Eurasian Eagle-owl Facts

• Eurasian Eagle-owls are the second-largest living owl.
• These owls suffered large losses in the 20^th century due to intentional killing.
• There are currently at least 12 recognized subspecies of Eurasian Eagle-owls, though the exact number may vary depending on the authority. The main one is Bubo bubo bubo.
• These owls can adjust the disc of feathers on their face to help them hear better.
• The shade of orange of a Eurasian Eagle-owl’s eyes varies based on the subspecies.

Where to Find Eurasian Eagle-owls

The Eurasian Eagle-owl lives in Europe, Asia, and northern Africa. Their range is extensive, covering more than 12 million square miles and dozens of countries. They inhabit areas from the cold, rocky coastlines of the Norwegian Sea south to Spain, Greece, and even Israel, Lebanon, Iraq, and Iran. They are also found across Asia, in Russia, China, across the Himalayas, and even as far east as Japan.

Eurasian Eagle-owls often prefer rocky, mountainous areas with cliffs, crevices, and caves. They may choose to live in abandoned quarries or gorges, along river valleys or coasts. In the north, from Norway to Siberia, they often inhabit the cold taiga forests. Farther south, they also typically live in or near forested areas, sometimes right up to the edge of the desert. They may reside near human civilization, particularly near water sources, open farmland, or even landfills and dumps, where they can find abundant food like rats and other rodents.

Over their expansive range, Eurasian Eagle-owls live at elevations from near sea level to high in the mountains. They manage well, even high in the Alps and the Himalayas at elevations of 14,000 to more than 15,000 feet.

Nests

These large owls most often build their nests high on rocky cliffs or hillsides. They nest on ledges, in crevices, or in cave entrances that provide a bit of shelter. Sometimes they nest in large trees, or rarely in holes in trees, and have, on occasion, been seen using abandoned nests of large birds like eagles, buzzards, or even storks. They do not build up nests, but instead lay their eggs upon naturally occurring surfaces or the materials left behind by other birds.

Classification and Scientific Name

The Eurasian Eagle-owl was originally described in 1758 by Linnaeus. He gave it the scientific name Strix bubo, with the Strix genus derived from Latin, meaning owl. By 1805, the horned owls were reassigned to the genus Bubo, with the Eurasian Eagle-owl as the type species. It was described as Bubo bubo by the French zoologist, André Duméril, who was working for the National Museum of Natural History in France.

Today, there are many owls in the Bubo genus, including the familiar Great Horned Owl, Bubo virginianus, which ranges from North America into Central and South America. It also contains the largest living owl in the world, Blakiston’s Fish Owl, Bubo blakistoni, which lives in parts of Russia, China, and Japan. The Snowy Owl, Bubo scandiacus, a vulnerable species native to northern latitudes, is another familiar member of the genus.

Although the Eurasian Eagle-owl is sometimes called simply “Eagle Owl,” this name is problematic. While Bubo bubo is the type species for the Bubo genus, most of the 19 currently named species within the genus are also called eagle-owls. These include the Pharaoh Eagle-owl, the Asiatic Eagle-owl, the Spotted Eagle-owl, the Philippine Eagle-owl, and several more. In addition, there are currently 12 subspecies of Bubo bubo listed on the Integrated Taxonomic Information System, although classifications are subject to change as more genetic data is collected.   

Appearance

Like other members of the Bubo genus, the Eurasian Eagle-owl is a horned owl. That means it has prominent, feathery tufts on its head that resemble horns. These tufts, known as plumicorns, can be more than 3 inches long and are mostly black with a thin buff or white rim.

The owl has large, orange eyes rimmed in black with striking black pupils. They can vary from pale to dark, reddish-orange, depending mainly on the subspecies. It has a facial disc of dense feathers that are light brown and speckled. Its beak is strongly curved and mostly black, with lighter feathers underneath.

This impressive bird is the second-largest owl living today. Females are larger than males, and they can grow to around 30 inches in length. The average length of a Eurasian Eagle-owl is between 22 and 27 inches. They weigh between about 6 and 9 pounds on average, but some males weigh less than 3 pounds, and some females have been recorded at more than 10 pounds. They are generally quite a bit larger than the Great Horned Owl, and only slightly smaller on average than the Blakiston’s Fish Owl.

Feather patterns

Eurasian eagle-owls have brown feathers that are mottled with dark, vertical streaks. They have barred wing and tail feathers that are highly visible in flight. Their wingspan averages between 4.5 and 6 feet, and their wings are full and broad with serrated structures on the leading feathers typical of nocturnal owls. They molt gradually over a period of several years, beginning when they are about a year old. The feathers on their underside are light-colored and lightly patterned with darker streaks. Their huge feet are covered in light feathers and feature long, dark talons tipped in black.    

Behavior

One might be much more likely to hear Eurasian Eagle-owls than to spot them, thanks to their loud and booming calls. The owl is called Uhu in Germany, a name derived from its call, which sounds like “OOH-hu” with emphasis on the first syllable. Males have a deeper call than the females, but both are loud and can be heard from long distances. The males usually call from a high perch, allowing their voices to travel farther and helping to deter rivals from entering their territory.

Pairs of Eurasian Eagle-owls are very territorial. They will fight other owls that try to come into the territory they have claimed. They will defend their nests and their young from potential nest predators, but they will also abandon their nests if they are too disturbed by human activity or other threats.

Eurasian Eagle-owls are adept hunters that usually fly at night. They are most active in the hours after sunset and before dawn. Their range, however, covers a significant amount of northern territory where nights are short for part of the year, so they may occasionally be seen hunting in the daytime as well. In other areas, if the owls are flying in the daylight, it is most likely because they are being harassed and driven from their resting place by ravens or crows.

Diet

Eurasian Eagle-owls are carnivores with a wide variety of prey, depending on what is most available within their territory. They are apex predators with special adaptations that help them to hunt at night. Their large eyes are highly adapted for night vision, and the facial disc of feathers helps amplify sounds. They usually hunt from a perch or on the wing, watching and listening for the movements of prey.

These owls eat all sorts of animals, particularly small rodents such as mice, voles, squirrels, and rats, or slightly larger mammalian prey such as rabbits, hedgehogs, and marmots. Some Eurasian Eagle-owls have killed and eaten young deer, antelope, and wild piglets.

They also prey on other birds, including shore birds, woodpeckers, and even other smaller owls. Eurasian Eagle-owls will eat amphibians, reptiles, and fish, and will even catch prey as small as insects.

Like other owls, the Eurasian Eagle-owl feeds its young meat torn from its prey. While females incubate the eggs and tend the nest the first few weeks after the offspring hatch, males hunt and provide food for both the female and the young.

Reproduction

Eurasian Eagle-owls are mostly monogamous and tend to mate for life. Mated pairs stick to the same general territory if possible, and often return to the same nest site year after year. Young male owls, after reaching sexual maturity around age 2, search for a mate by vocalizing. They sing their loud, deep, “OOH-hu” song from high vantage points within their chosen territory, which may cover an area of up to 5 to 30 square miles. Once a female responds, courtship begins, and when she is ready, she joins the male on a perch to mate.

Males choose potential nest sites but do little to nothing to improve the site, other than a bit of scratching if dirt is present. Females give final approval, then lay an average of 2 eggs (usually 1 to 4) in the nest. Incubation averages 31 to 36 days, with eggs hatching in the order in which they were laid. The female incubates the eggs and stays on the nest with the hatchlings for the first few weeks. Males hunt and bring prey to the nest.

Eurasian Eagle-owl chicks (owlets) emerge downy and brownish-gray. Their eyes don’t open until they are a few days old, but they grow very quickly. The young can eat whole prey after about 3 weeks. Depending on the location of the nest, they might venture out between 5 and 8 weeks, with ground-dwelling birds leaving earlier. The parents still care for them and feed them, though, even after they begin to fly. They are generally independent by 20 to 24 weeks.

Nestcams

Owl nestcams are quite popular, and both live and recorded webcam footage of Eurasian Eagle-owls can be found in many places online. The German site, Uhu Webcam, hosted by the Stefan Brücher Society for the Conservation of Owls, is one such resource, with archival recordings in the Highlights section of the site dating back to 2009.

Predators & Threats

Adult Eurasian Eagle-owls have no natural predators. Nestlings and young owls could fall prey to other predators, but thanks to their fiercely protective mothers and natural camouflage, the risk is low.

Humans are the greatest danger to these beautiful owls. Intentional persecution, including shooting, poisoning, and egg collection, has long been a problem, causing a significant decline in the population over the 20^th century. Today, unintentional deaths are a bigger risk. Pesticides used on rodents can easily poison the owls that eat them. Vehicle strikes and collisions with power lines and fences are another serious problem. Human activity can force the birds from their familiar territory and even cause them to abandon their nests. Additionally, pollution from persistent organic pollutants (such as PCBs) and collisions with wind turbines have emerged as significant threats in recent years.

Lifespan of the Eurasian Eagle-owl

These owls have lived more than 60 years in captivity, but average only about 20 years in the wild. The oldest recorded individual reached nearly 28 years. The Eurasian Eagle-owl is listed as a species of least concern by the IUCN Red List of Threatened Species. Its population is estimated at between 180,000 and 300,000 individuals, but numbers are believed to be decreasing.