The lower breast and belly feathers are creamy-brown to tawny buff to off-white with a variable amount of fine dark wavy barring, on a tawny-buff ground colour.

Also, owls with white throat patches such as the Eurasian eagle-owl are more likely to be active in low-light conditions in the hours before and after sunrise and sunset rather than the darkest times in the middle of the night.

The boreal and barn owls, to extend these examples, lack obvious visual cues such as white throat patches (puffed up in displaying eagle-owls), again indicative of primary activity being in darker periods.

Nevertheless, the latter is still distinctively an ear-tufted Eurasian eagle-owl and lacks the pure white background colour and variable blackish spotting of the slightly smaller species (which has relatively tiny, vestigial ear tufts that have only been observed to have flared on rare occasions).

Fish owls are distinctively different looking, possessing more scraggy ear tufts that hang to the side rather than sit erect on top of the head, and generally have more uniform, brownish plumages without the contrasting darker streaking of an eagle-owl.

Based on an extensive fossil record and a central distribution of extant species on that continent, Bubo appears to have evolved into existence in Africa, although early radiations seem to branch from southern Asia, as well.

[76] Compared to golden eagles, though, they can visit cultivated land more regularly in hunting forays due to their nocturnal habits, which allow them to largely evade human activity.

[77] Although found in the largest numbers in areas sparsely populated by humans, farmland is sometimes inhabited, and they even have been observed living in park-like or other quiet settings within European cities.

European hares (Lepus europaeus), the often preferred prey species by biomass of the eagle-owls in their natural habitat, live only in rural areas of Finland, not in the city centre.

[100] The territorial song, which can be heard at great distance, is a deep resonant ooh-hu with emphasis on the first syllable for the male, and a more high-pitched and slightly more drawn-out uh-hu for the female.

[8] Annoyance at close quarters is expressed by bill-clicking and cat-like spitting, and a defensive posture involves lowering the head, ruffling the back feathers, fanning the tail and spreading the wings.

[27] The Eurasian eagle-owl rarely assumes the so-called "tall-thin position", which is when an owl adopts an upright stance with plumage closely compressed and may stand tightly beside a tree trunk.

[8] The Eurasian eagle-owl is a broad-winged species and engages in a strong, direct flight, usually consisting of shallow wing beats and long, surprisingly fast glides.

[103] There are additionally claimed cases from Russia of Eurasian eagle-owls moving south for the winter, as the icebound, infamously harsh climate there may be too severe even for these hardy birds and their prey.

Similarly, Eurasian eagle-owls living in the Tibetan highlands and Himalayas may in some anecdotal cases vacate their normal territories when winter hits and move south.

In both of those examples, these are old, unverified reports and there is no evidence whatsoever of consistent, annual migration by Eurasian eagle-owls and the birds may eke out a living on their normal territories even in the sparsest times.

The high prominence of singing perches allows their song to be heard at greater distances and lessens the need for potentially dangerous physical confrontations in the areas where territories may meet.

[27] The male selects breeding sites and advertises their potential to the female by flying to them and kneading out a small depression (if soil is present) and making staccato notes and clucking noises.

[8][19] While it may seem contrary to the species' highly territorial nature, there is one verified cases of polygamy in Germany, with a male apparently mating with two females, and cooperative brooding in Spain, with a third adult of undetermined sex helping a breeding pair care for the chicks.

[19][10] Occasionally if cornered both adults and nestlings will do an elaborate threat display, also rare in owls in general, in which the eagle-owls raise their wings into a semi-circle and puff up their feathers, followed by a snapping of their bills.

While variation based on climate is not unusual for different wide-ranging palearctic species, the higher clutch size of western Mediterranean eagle-owls is also probably driven by the presence of lagomorphs in the diet, which provide high nutritional value than most other regular prey.

In the Italian Alps, heavier rainfall during breeding decreased fledgling success because it inhibited the ability of the parents to hunt and potentially exposed nestlings to hypothermia.

[19][22] Until they are able to establish their own territories, young eagle-owls spend their lives as nomadic "floaters", and while they also call, select inconspicuous perch sites unlike breeding birds.

Insulation of pylons is thought to result in a stabilisation of the local population due to floaters taking up residence in unoccupied territories that formerly held deceased eagle-owls.

There, very few areas are not heavily modified by human civilisation, thus exposing the birds to the risk of collisions with deadly man-made objects (e.g. pylons) and a depletion of native prey numbers due to ongoing habitat degradation and urbanisation.

[140] Unanimously, biologists studying eagle-owl mortality and conservation factors have recommended to proceed with the proper insulation of electric wires and pylons in areas where the species is present.

[142] Large reintroduction programs were instituted in Germany after the eagle-owl was deemed extinct in the country as a breeding species by the 1960s, as a result of a long period of heavy persecution.

[119] Apparently, the German reintroductions have allowed eagle-owls to repopulate neighbouring parts of Europe, as the breeding populations now occurring in the Low Countries (the Netherlands, Belgium, and Luxembourg) are believed to be the result of influx from regions further to the east.

[110] The flooding of the land bridge between Britain and continental Europe may have been responsible for their extirpation as they only disperse over limited distances, although early human persecution presumably played a role as well.

Among the species considered at least vulnerable (up to critically endangered as in the mink and eel, both heavily overexploited by humans) to extinction known to be hunted by Eurasian eagle-owls are Russian desman (Desmana moschata)[148] Pyrenean desman (Galemys pyrenaicus),[149] barbastelle (Barbastella barbastellus),[150] European ground squirrel (Spermophilus citellus),[151] southwestern water vole (Arvicola sapidus),[152] European mink (Mustela lutreola),[153] marbled polecat (Vormela peregusna),[148] lesser white-fronted goose (Anser erythrops),[154] Egyptian vulture (Neophron percnopterus),[155] greater spotted eagle (Clanga clanga),[156] eastern imperial eagle (Aquila heliaca),[156] saker falcon (Falco cherrug),[157] houbara bustard (Chlamydotis undulata),[148] great bustard (Otis tarda),[154] spur-thighed tortoise (Testudo graeca),[158] Atlantic cod (Gadus morhua),[159] European eel (Anguilla anguilla)[159] and lumpfish (Cyclopterus lumpus).