Eurasian Eagle Owl (Bubo bubo)

Eurasian eagle owl

The Eurasian eagle owl, also known as Uhu, rock eagle owl, european eagle owl, or just eagle owl, is one of the largest owls in the world, with a wingspan of about six feet and weighing almost three pounds. These beautiful birds are found throughout Europe and Asia, with some populations living as far south as northern Africa.

They’re generally monogamous and often mate for life, although they will find another partner if their first dies. Unlike many other owls, Eurasian eagle owls are mostly nocturnal, meaning they’re most active during the night.

They are one of the largest European owls and among the heaviest owls in the world; although some other species such as Blakiston’s fish owl and Ural owl are heavier on average, there are several reported cases of Eurasian eagle owls weighing as much as 2.7 kg. It has a total length of roughly 55 – 75 cm (22 – 30 inches), with females being noticeably larger than males.

Description

Eurasian eagle owl

The Eurasian eagle owl, also known as the European eagle owl, is a very large bird found in Europe and parts of Asia. It is one of the largest owls in the world, but at 30 inches, it has only about double the length of an average Great Horned Owl. Their habitat includes woodland, coniferous forests, and mountains from Spain to Mongolia.

The Eurasian eagle owl typically roosts by day and hunts for prey at night. Its diet consists mainly of small mammals such as hares, rabbits, and rodents. Hunting usually takes place close to dusk or dawn when these animals are more active and easier to catch than during the middle of the day. The Eurasian eagle owl’s incredible hearing allows it to pinpoint its prey’s location from several hundred meters away.

Scientific name

The scientific name of the Eurasian eagle owl is Bubo bubo

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Eurasian eagle owl habitat

Eurasian eagle owls can be found in woodlands, deserts, mountains, open grasslands, and riverbeds. For a nesting site, they prefer rocky landscapes and make a shallow nest depression in a rocky site that also has available water and food resources.

Eurasian eagle owl size and weight

The Eurasian eagle owl is a large species of owl that grows to an average size of about 55 – 75 cm (22 – 30 in) in length, they have an average weight of around 2.7 kg. Eurasian eagle owl wingspan is around 188 cm (74 inches). Female Eurasian eagle owls are usually larger than males and have more prominent ear tufts.

Feathers and plumage

Eurasian eagle owl

This type of bird has tufts of feathers on the ears, giving it a distinctive appearance. Its upper parts are primarily dark, while its underparts are mostly yellowish-brown. It is barred on the wings and tail. Its underparts are variably colored buffs with darker streaks. The facial disc can be seen, but the orange eyes are distinctive.

Molting

Eurasian eagle owls will shed their feathers every year. Molting occurs from October to November and may be a reason for not eating, or possibly dying during this time. The shedding process starts with the owl preening the first set of feathers around the head and breast areas, those on top of the head are broken off and swallowed.

Feathers start coming out through a line that is made by preening more feathers, these are also eaten in most cases. New feathers form below, which push out the old ones as they grow back in. It is possible that some molted feathers get ingested before they are broken off at the base and therefore have to pass through the digestive system again.

A new downy layer of insulation grows between six weeks and three months after molting has finished, making it difficult for people to tell whether an owl has recently molted.

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Nesting behavior

Eurasian eagle owls make their nests in the tops of trees or other elevated areas. These owls often reuse the same nest year after year, repairing it and reinforcing it as needed. The female does most of the work during nesting season. Often her mate will bring her food while she is working on their future home.

Often, they also nest on ledges, cave entrances, and within rock crevices on cliff faces. They may also use abandoned nests of other large birds, such as ravens or eagles, and some even nest on the ground.

Diet and foraging

The Eurasian eagle owl primarily eats small to medium-sized mammals, such as hares, rodents, and squirrels. When hunting for food it employs perch hunting which means it will stand still and then swoop down onto its prey when it feels the time is right.

Eurasian eagle owl sound and vocal behavior

Calls include a loud, hooting whoo-hoo-hoo noise, often given in sets of four to ten. Eurasian eagle owls can also make deep booming calls. This deep call is made by males to attract females and scare off other males from their territory.

Breeding

Eurasian eagle owl

Eurasian eagle owls generally begin breeding around one to three years of age, and will often only mate once a year.

Courtship begins in late fall and mating occurs in January or February. Mated pairs use a special type of clucking and brief staccato vocalizations to find each other. The nest can be found in crevices, cave entrances, or sheltered ledges of rocky, underground areas.

Their eggs are usually white, and they usually lay 1 to 4 of them. While the female incubates them, the male provides food for the female.
Eurasian eagle owl baby has a strong tendency to imprint on the first animal it sees, so releasing captive-bred Eurasian eagle owl baby into the wild is very difficult.

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Eurasian eagle owl lifespan

As adults, Eurasian eagle owls typically live for 20 years in the wild and up to 60 years in captivity.

Movements and migration

The Eurasian eagle owl is the largest of the world’s owls and is found all over Europe, Asia, and North Africa. These creatures spend their winters in large numbers in south-central Asia and then gradually spread out to other regions as spring progresses. In late summer, they return to their winter home.

Eagles owls are migratory but do not make annual round trips like many other bird species. Instead, these birds are nomadic and move with the seasons. During the winter months, they live in southern Asia while during warmer weather they can be found throughout most of Europe, North Africa, Russia, and Central Asia.

Diseases and threats

Eurasian eagle owls are threatened by a number of diseases, including aspergillosis and avian cholera. These are usually contracted from exposure to other infected animals, and can eventually lead to septicemia in the owls if not treated. Cats, dogs, and rats may transmit these illnesses when they come into contact with owl droppings or feathers that have been tainted with the bacteria.

Eurasian eagle owls are also threatened by humans through habitat destruction and deforestation. The increase in logging activity has greatly diminished their living space, which often forces them to move away from the area. Furthermore, many old-growth forests are being replaced with younger forests due to logging activity. The removal of mature trees leads to a loss of nesting sites for the owls.

Population status

The breeding population in Europe is around 18,500-30,300 pairs, which is equivalent to 36,900-60,600 mature individuals.

An estimate of the global population size is 180,000 to 300,000 mature individuals based on 20% of the global range, although further validation is needed.
As a result, the population is counted at anywhere from 100,000 to 499,999 mature individuals.

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Conservation and management

The Eurasian eagle owl is listed as a Near Threatened species by the IUCN and its range of distribution is declining. It is not listed under CITES, nor do any national conservation laws protect it.

The IUCN’s Houghton Red List suggests that human disturbance from logging, oil exploration, and gamekeeping could threaten their habitat and population size. Furthermore, increased traffic noise in the form of roads can disrupt nesting and foraging behavior.

On the other hand, some areas are preserved to maintain healthy populations of owls like Kazbegi National Park in Georgia. A survey done by Georgian biologists found 17 pairs on or near Mount Kazbek. They say that due to illegal hunting and habitat loss, this number should be at least 30-40 pairs.