Eurasian Eagle Owls: Information, Pictures and Conservation
The Eurasian Eagle Owl.
The Eurasian Eagle Owl, or European Eagle owl as it is more commonly known, is one of the largest of owl species. Incorrectly, the Eagle owl is frequently described as the largest of owls, however in terms of length, that particular honor belongs to the Great Grey and the Blackiston's Fish Owl is arguably heavier.
Nevertheless, the Eurasian is, quite frankly, a powerful and imposing creature reaching up to 30 inches in length at maturity, having a wingspan of up to 70 inches and females, who are on average a third heavier than their male counterparts, can weigh anything up to 9.3 lbs.
To put this into some perspective, the species is almost four times larger and eight times heavier than a barn owl. This bird is no featherweight, if you'll pardon the pun.
There are no fewer than 13 subspecies of the Eurasian, which is a member of the Strigidae (true owl) family.
Eurasian Eagle Owl Description
There are some notable differences in appearance when it comes to the subspecies, however, the one thing they all have in common is the most distinctive eye coloring which ranges from a vivid amber /orange to orange/ yellow, and prominent ear tufts. The Bubo bubo (nominate race) has a heavily speckled crown and head of buff brown with black streaking across the sides and back of the neck and nape. Typically the throat and chin are white with a black to greyish facial disk, depending on the region and the sub species. The beak is black and fine brown barring can be found on the owls' underbelly.
The toes are extremely long, powerful and feathered and as is the case with all owls the Eurasian is zygodactile, meaning that the fourth digit on each foot can be reversed, and will therefore, point either backwards or forwards as required. Talons are not only black, but longer than a leopards claw.
Unlike other birds, owls' eyes are set forward which greatly enhances depth perception, but doesn't allow the owl to rotate its eyes in order to change view. But just like other birds the Eurasian needs a wide visual range in order to detect predators and prey. For this reason, owls including the Eurasian have particularly flexible necks, which means they can literally rotate their heads 270 degrees either way.
And it's no coincidence that this species has vivid eye coloring, in fact, the various shades of eye color tells us quite a lot about their hunting preferences and behaviour. The subspecies with yellow eyes will hunt mainly during the day, whilst the Eurasians with vivid orange eyes can hunt both during the day and at night. Although nearsighted, every subspecies of the Eurasian has excellent day vision.
Photos of the Eurasian Eagle OwlClick thumbnail to view full-size
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Eurasian Eagle Owl Behavior, Flight and Hunting
Largely nocturnal, the species tends to be most active at dawn and dusk, and hunting will mainly occur from and an open perch or whilst the bird is in flight.
Due to its size and hunting prowess, the Eurasian is at the top of the avian food chain, feeding on small mammals such as rabbits to juvenile deer, birds as large as buzzards, reptiles, amphibians, fish, insects and in some cases, domestic cats and dogs. Because the owl has no sense of smell, it has even been known to capture and feed on skunks.
This bird does not tear the meat from the bodies of its prey, but ingests the complete caucus. Later, the bird will regurgitate a single pellet which consists of bone, feathers, fur and any other matter which the owl cannot digest.
Eurasian Eagle Owl Slow Motion
Flight is almost completely silent, and as with all owls the Eurasian has evolved feathers which buffer the air as opposed to cutting through through the air like a Falcon or an Eagle. And of course, just as with other owls, their hearing and vision are exceptional, enabling them to detect prey from some distance.
In comparison to birds of prey such as the falcon or hawk however, the Eurasian lacks the necessary speed required to successfully hunt during the day when accompanied by a handler, which is why falconers will rarely fly the bird for hunting purposes; the owls are greatly hindered by their noisy human partners.
The Eurasian hunts by stealth, precision and highly advanced senses, not speed.
When unaccompanied, and when the bird's intended prey comes to realise the inevitable danger, it's far too late. Nature's silent assassin has struck.
The Eurasian will either crush its prey with their large powerful talons, believed to an exert a pressure of more than 750lbs per square inch, or use its powerful beak to bite the victim's head.
One could be excused for believing that the large ear tufts would help amplify the birds hearing, when in reality the tufts have no hearing function whatsoever. In the owls' natural habitat they're used for camouflage and communication.
When the feathers on the tufts are erect, it is widely believed that the bird is making itself visible to other owls, therefore assisting family members to identify the bird when it is situated in dense woodland. When erect, the tufts also exaggerate it's size, making the Eurasian appear more formidable when faced with predators or other perceived threats.
During sleep the tufts are lowered which alters the shape of the head, this assists the Eurasian to take up the shape and contours of the bark on nearby trees.
When able to sleep on a flat surface, they will stand on their elbows, resting and curling their toes.
The Eurasian's facial expression and posture will often indicate it's mood. For example, when the feathers above the beak are pulled forward and the ear tufts are raised (imagine the equivalent of a frown) the bird is showing signs of irritation.
When they feel threatened however, they will puff out their feathers,lifting their wings upwards above their head and also hiss.
Watch the video beneath where the Eurasian demonstrates the "threat posture."
Eurasian Eagle Owl Threat Posture
Eurasian Eagle Owl Call
Eagle owls are solitary creatures, fiercely protecting their territory from predators, yet, they respect the territory of other owls and will only the overlap the boundaries when food is in short supply.
Whenever possible, the bird prefers to remain in the same territory, only moving when they either forced out or the food supply becomes sparse.
The Eurasian is a particularly vocal creature, using a range of clucks and hoots which represent different moods. They will use specific vocals when entering or leaving territories, or to attract a mate.
A territorial call consists of a deep "oohu-oohu-oohu" which is repeated approximately every ten seconds. The female's call is noticeably higher pitched. When threatened the bird may emit a " ka ka kau", grunt and also hiss.
Eurasian Eagle Owl Courtship and Reproduction
Eurasian Eagle Owls will use a low frequency gutteral hoot to attract a potential mate, and both the male and female of the species will reach sexual reproductive maturity between the ages of one and three years. The breeding season only occurs once a year and pairs will normally form during early fall. Once a mate has been selected, the partnership is lifelong, although not necessarily monogamous. The newly formed couple will then begin nesting in the latter part of January and early part of February.
It is quite common for the owls to occupy the abandoned nests of other large birds, and prefer rock crevices, caves, and sheltered cliff ledges in which to do so.
The breeding season lasts from December to April and the rate of breeding will increase or decrease in direct correlation to the availability of food. In light of this, the female can lay anything between one and four white eggs, depending on the quality of their environment.
Eggs are incubated by the mother for approximately 30 to 36 days, whilst her partner will protect from predators and supply food. The newly hatched infants are covered with a buff coloured down.
As with many other birds, owlets are imprinted by the first creature they see, known as genetic imprinting. When hatched in captivity without owls for parents, the owlets will intimate a human, in other words, they will believe that they are human. After hatching, the male will continue to provide his mate with food for up to two weeks, whilst the female protects the young from any threats.
At approximately three weeks of age the owlets are able to feed independently, and at around five weeks of age the chicks are able to walk around the nesting area. By approximately the eighth week, the chicks will learn to fly, but only for short distances.
Around September to November the young owls will leave the nest. The lifespan of the Eurasian Eagle Owl varies considerably depending upon whether it is kept in captivity, or in the wild. In it's natural habitat life expectancy is around 20 years, in stark contrast to captive owls who can live for up to sixty years.
Risk of predation is very low for adult Eurasians, who have no natural enemies.
Eurasian Eagle Owl Habitat, Range and Subspecies
The Eurasian is a hardy creature, and occupies a diverse range of habitats and extreme temperatures; from deserts to riverbeds; from mountain ranges to flat, open grasslands. Nevertheless, they prefer wooded areas and rocky landscapes, but can adapt exceedingly well.
The European Eagle Owl can be found across Europe to Russia and the Pacific, through Pakistan across to Korea and China and across Iran.
The size of subspecies decreases North to South and East to West of the range. Similarly, the owl's coloring becomes paler as we move from north to south in the Middle East and Asia Minor, and also as we move eastwards in the northern parts of the range to western Siberia.
In contrast, the birds plumage becomes progressively darker as we move towards the Pacific.
Distribution of the Eurasian Eagle Owl
Subspecies by Range
B.b.bubu - central and northern Europe.
B.b hispanus- Iberian Peninsula.
B.b. ruthenus - Russia from the east of Moscow to Urals.
B.b interpoistus - From the Ukraine and then south to Syria.
B.b. Sibericu- Western Siberia from the Urals to the River Ob.
B.b.yenisseensis- Central Siberia from the River Ob to Lake Baikal.
B.b.jakutensis- From Lake Baikal, Northeaster Siberia to the Pacific.
B.b.ussuriensis- From Southeastern Siberia through to Northern China.
B.b.turcomanus- From the region of Volga through to Kazachstan and western Mongolia.
B.b.omissus- Found in Turkey.
B.b.nikolskii- Found in Southern and central Iran through to Pakistan.
B.b.hemachalana- Can be found in Tien Shan, Tibet, the Himalayas and Pamirs.
B.b.kiautschensis- Found in Korea and China.
B.b.swinhoei- Can be found in Southeastern China.
What Does Endangered Really Mean?
What does endangered really mean? When an animal or plant species becomes endangered there are consequences for us. Read What does endangered mean? What is an endangered animal and does it matter? for more information.
Eagle Owls in Britain
During the last century the Eurasian was very much in decline, due to human persecution, road traffic accidents, power lines, barbed wire, toxic mercury seed dressings and pesticide use. Myxomatosis and rabbit haemorrhagic disease have significantly reduced rabbit populations in some regions, which has also had detrimental effects on the Eurasian population.
However in Europe, the owl has made some recovery in terms of population. Which in part is due to improved and increased protection under the Convention on the Conservation of European Wildlife and Natural Habitats, and the EC Birds Directive. Increased food supply; growing populations of rats and rodents due to tip proliferation and widespread restocking programs are also, in part, responsible for the Eurasian's recovery. As such, the owl's survival is not considered to be threatened. Nevertheless, the population still remains below former levels.
Until recently, it was believed that the Eagle Owl was all but absent from the UK, and had not occurred here naturally since the last Ice Age more than 10,000 years ago. That is, until the European Eagle was discovered in the Forest of Bowland Wells, Lancashire, Northern England.
Whilst many ornithologists were delighted by the news, the owl's presence on the Island has caused some controversy.
As a top predator, there are some concerns that the Eurasian may have a significant impact on the Island's fauna. Particularly at risk some would argue, are Britain's Hen Harrier population. The remains of several Hen Harriers have been found where the Eurasian is nesting, and with fewer than 20 pairs throughout the country, this has caused concern.
Those who are encouraged by the presence of the Eurasian in the UK, argue that Hen Harriers and Eagle Owls coexist in parts of Europe without threatening the others survival.
In contrast, those who are concerned about the possible impacts of the Eurasian on Britain's wildlife, argue that there is no evidence that the Eurasian is naturally occurring here, and the birds are thought to have been previously kept in captivity.
If evidence is found that the Eurasian is naturally occurring in Britain, the birds will be given full protection under the law. If the opposite is found to be the case, and the owl's presence has been proven to have a detrimental effect on the country's fauna, it is possible that the birds may be culled.
At the time of writing, the Eurasian is being monitored and attempts will be made, over a period of time, to establish whether the regions wildlife has been adversely affected by the presence of the owl. The Eurasian is safe, for now.
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