Species Fact Profile: Eurasian Eagle Owl (Bubo bubo)

                                                                     Eurasian Eagle Owl

Bubo bubo (Linnaeus, 1758)

Range: Europe and Asia below the Arctic Circle, as far south as the Persian Gulf and extreme North Africa.  Does not occur in Southeast Asia or the Indian Subcontinent

Habitat: Woodland, Tundra, Desert, Grassland, Scrub - favors rocky areas with cliffs and ravines, as well as open country for hunting

Diet: Primarily small mammals such as rodents, rabbits, and hedgehogs, but will take prey the size of foxes and deer fawns.  Will also eat birds (including smaller owls) as well as reptiles, amphibians, fish, and large invertebrates

Social Grouping: Primarily solitary, but will pair up during courtship.  Territorial, home ranges overlapping only slightly

Reproduction: Monogamous, may be for life.  Nest in January or February.  Nest in crevices, caves, or on the ground at the base of trees, may use abandoned nests from other birds.  Lay 1-4 eggs per season, depending on availability of food.  Female incubates the eggs for 31-36 days while the male hunts for both partners.  Chicks are capable of feeding themselves at 3 weeks, can walk at 5 weeks and can make short flights at 2 months.  Driven from nest in the fall.  Sexually mature at 2 years old.

Lifespan: Estimated 20 Years in Wild, up to 60 Years in Human Care

Conservation Status: IUCN Least Concern, CITES Appendices II and III

• Generally considered to be the world’s largest owl species.  Females are larger than the males.  Measure 58-71 centimeters long with a wingspan of 1.5-2 meters, and weigh 1600-4200 grams.  Their average size tends to decrease from North to South and from East to West, with the largest birds in the northeastern portion of the range
• Sexes look alike.  Primarily brown-black or tawny-buff in color with prominent ear tufts (6.4-8.7 centimeters long) and a facial disk heavily marked with black, gray, and white.  Upper parts are darker than the lower parts.  The throat is white, and there is some black streaking on the lower body.  Eyes are a very pronounced orange (good identifier – the eyes are yellow in most other eagle owls, such as the great horned owl)
• Hunt through a combination of excellent sight and hearing, the later facilitated by the fact that their wings make almost no noise when flapping, allowing the owl to hear better.  Hearing isn’t as sophisticated as it is in some other owls, suggesting sight may be the most important
• Mostly nocturnal, but in times of scarcity they will hunt during the day to find more prey.  Otherwise, days are spent inactive, roosting in trees
• Eggs and owlets are vulnerable to nest raiders (especially in cases where the birds nest on the ground), but adults have no significant predators.  Nests are especially vulnerable in times of scarcity, when both parents may have to leave the nest to find sufficient food.  There have been documented cases of eagles kill eagle owls
• Over a dozen recognized subspecies.  The nominate is the European eagle owl, found over most of Europe from Scandinavia to the Balkans.  Other subspecies include the Iberian (B. b. hispanus), the South China (B. b. swinhoei), and the Ussuri (B. b. ussuriensis) in Siberia.  
• Sensitive to habitat disturbance, especially when nesting, and will abandon nest if approached too closely (outdoor activities such as skiing and mountaineering can disrupt breeding).  At the same time, they will forage in cultivated lands more often than other large raptors, since their nocturnal lifestyle allows them to do so while avoiding humans
• Sometimes persecuted directly either through shooting or poisoning (in the later case, the owls may be deliberate or accidental targets of the poison), also killed through car collisions and collisions with power lines (electrocution is the most important cause of mortality) or barbed wire fencing.  Additional threat is collection of eggs by poachers
• Underwent significant decline in southern Europe in the 1960s due to the crash of rabbit populations caused by myxomatosis
• Reintroduction programs underway in parts of northern and western Europe, including the United Kingdom, where the species had long been considered extinct.  Population is also benefiting from proliferation or rodents and other prey species associated with human activity (such as rats and pigeons) in some areas
• Eurasian eagle owls pose local conservation challenges due to their predation of some endangered species, such as Russian desman, houbara bustard, and European mink