The Eagle Owl is a large and powerful bird, smaller than the Golden Eagle but larger than the Snowy Owl. It is sometimes titled the world’s largest owl, but so is the Blakiston’s Fish Owl, which is slightly bigger on average. The Eagle Owl has a wingspan of 138–200 cm (55–79 in) and measures 58–75 cm (23–30 in) long. Females weigh 1.75-4.2 kg (3.9-9.4 lbs) and males weigh 1.5-3.2 kg (3.3-7 lbs). In comparison, the Barn Owl weighs about 500 grams (1.1 lbs). It mainly feeds on small mammals in the 200-2,000 gram (0.44-4.4 lb) weight range, such as voles, rats, mice and hares. However, prey can be killed up to the size of foxes and young deer (up to 17 kg/37 lb), if taken by surprise. The other significant group of prey is other birds and almost any type of bird is potential prey. Common avian prey include corvids, grouse, woodpeckers, other raptors and, especially near coastal areas, ducks, seabirds and geese. Larger prey (over 3 kg/7 lb) is consumed on the ground which leaves the bird vulnerable (for example to foxes). It is said to be routinely able to swallow a hedgehog whole.
The call of the Eagle Owl is a deep resonant “ooh-hu” with emphasis on the first syllable for the male, and a more high-pitched uh-Hu for the female (in German and Hungarian, the name of this bird is “Uhu”, the Turkish name is “Puhu”, the Polish name is “Puchacz”, and the Dutch name is “Oehoe”). Each member of an Eagle Owl population can be identified by means of its vocalizations.
The size, ear tufts and orange eyes make this a distinctive species. It has a strong direct flight. The ear tufts of males are more upright than those of females.
The Eagle Owl is largely nocturnal and is found in mountains and forests with cliffs and rocky areas, usually nesting on cliff ledges. Laying generally begins in late winter, sometimes later. One clutch per year of 1-4 white eggs are laid, measuring 56-73mm x 44.2- 53mm (2.2- 2.9″ x 1.7- 2.1″) and weighing 75- 80g (2.6- 2.8oz). They are normally laid at 3 days intervals and are incubated by the female alone, starting from the first egg, for 31-36 days. During this time, she is fed at the nest by her mate. Once hatched, the young are brooded for about 2 weeks; the female stays with them at the nest for 4-5 weeks. For the first 2-3 weeks the male brings food to the nest or deposits it nearby, and the female feeds small pieces the young. At 3 weeks the chicks start to feed themselves and begin to swallow smaller items whole. At 5 weeks the young walk around the nesting area, and at 52 days are able to fly a few metres. They may leave ground nests as early as 22-25 days old, while elevated nests are left at an age of 5-7 weeks. Fledged young are cared for by both parents for about 20-24 weeks. They become independent between September and November in Europe, and leave the parents’ territory (or are driven out by them).
Eagle Owls have also been observed living in European cities. Since 2005, at least five couples have nested in Helsinki. The number is expected to increase due to the growth of the European rabbit population in Helsinki.
In June 2007, an Eagle Owl nicknamed ‘Bubi’ landed in the crowded Helsinki Olympic Stadium during the European Football Championship qualification match between Finland and Belgium. The match was interrupted for six minutes. After tiring of the match, following Jonathan Johansson’s opening goal for Finland, the bird left the scene. Finland’s national football team have had the nickname Huuhkajat (Finnish for Eurasian Eagle-owls) ever since. The owl was named “Helsinki Citizen of the Year” in December 2007.
I managed to find this video of a wild eagle owl flying and hunting, There are not many.