Eurasian Eagle-owl

The Eurasian eagle-owl is largely nocturnal in activity, as are most owl species, with its activity focused in the first few hours after sunset and the last few hours before sunrise. In the northern stretches of its range, partial diurnal behaviour has been recorded, including active hunting in broad daylight during the late afternoon. In such areas, full nightfall is essentially non-existent at the peak of summer, so eagle-owls must presumably hunt and actively brood at the nest during daylight. The Eurasian eagle-owl has a number of vocalizations that are used at different times. It will usually select obvious topographic features such as rocky pinnacles, stark ridges and mountain peaks to use as regular song posts. These are dotted along the outer edges of the eagle-owl's territory and they are visited often but only for a few minutes at a time. Vocal activity is almost entirely confined to the colder months from late fall through winter, with vocal activity in October through December mainly having territorial purposes and from January to February being primarily oriented towards courtship and mating purposes. 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. It is not uncommon for a pair to perform an antiphonal duet. The widely used name in Germany as well as some other sections of Europe for this species is uhu due to its song. At 250–350 Hz, the Eurasian eagle-owls territorial song or call is deeper, farther-carrying and is often considering "more impressive" than the territorial songs of the great horned owl or even that of the slightly larger Blakiston's fish owl, although the horned owl’s call averages slightly longer in duration. Other calls include a rather faint, laughter-like OO-OO-oo and a harsh kveck-kveck. Intruding eagle-owls and other potential dangers may be met with a "terrifying", extremely loud hooo. Raucous barks not unlike those of ural owls or long-eared owls have been recorded but are deeper and more powerful than those species’ barks. 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. 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. Among others, the long-eared owl is among the most often reported to sit with this pose. The great horned owl has been more regularly recorded using the tall-thin, if not as consistently as some Strix and Asio owls, and it is commonly thought to aid camouflage if encountering a threatening or novel animal or sound. 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. It has, unusually for an owl, also been known to soar on updrafts on rare occasions. The latter method of flight has led them to be mistaken for Buteos, which are smaller and quite differently proportioned. Usually when seen flying during the day, it is due to being disturbed by humans or mobbing crows. Eurasian eagle-owls are highly sedentary, normally maintaining a single territory throughout their adult lives. Even those near the northern limits of their range, where winters are harsh and likely to bear little in food, the eagle-owl does not leave its native range. There are cases from Russia of Eurasian eagle-owls moving south for the winter, as the icebound, infamously harsh climate there is too severe even for these hardy birds and their prey. Similarly, Eurasian eagle-owls living in the Tibetan highlands and Himalayas may in some cases vacate their normal territories when winter hits and move south. Even in those two examples, there is no evidence 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.

While the eagle-owl remains reasonably numerous in some parts of its habitat where nature is still relatively little disturbed by human activity, such as the sparsely populated regions of Russia and Scandinavia, concern has been expressed about the future of the Eurasian eagle-owl in western and central Europe. 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. In Spain, long-term governmental protection of the Eurasian eagle-owl seems to have no positive effect on reducing the persecution of eagle-owls. Therefore, Spanish conservationists have recommended to boost education and stewardship programs in order to protect eagle-owls from direct killing by local residents. 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. As this measure is labour-intensive and therefore rather expensive, few efforts have actually been made to insulate pylons in areas with few fiscal resources devoted to conservation such as rural Spain. In Sweden, a mitigation project was launched in order to insulate transformers that are frequently damaged by eagle-owl electrocution. 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. The largest reintroduction there occurred from the 1970s to the 1990s in the Eifel region, near the border with Belgium and Luxembourg. The success of this measure, consisting in more than a thousand eagle-owls being reintroduced at an average cost of $1,500 US dollars per bird, is a subject of controversy. It appears that those eagle-owls reintroduced in the Eifel region which are able to breed successfully, enjoy a nesting success comparable with wild eagle-owls from elsewhere in Europe. On the other hand, mortality levels in the Eifel region appear to remain quite high due to anthropogenic factors. There are also concerns about a lack of genetic diversity of the species in this part of Germany. Apparently, the German reintroductions have allowed eagle-owls to repopulate neighbouring parts of Europe, as the breeding populations now occurring in the Low Countries (Netherlands, Belgium and Luxembourg) are believed to be the result of influx from regions further to the east. Smaller reintroductions have been done elsewhere and the current breeding population in Sweden is believed to be primarily the result of a series of reintroductions. Conversely to numerous threats and declines incurred by Eurasian eagle-owls, areas where human-dependent non-native prey species such as brown rats (Rattus norvegicus) and rock pigeons (Columba livia) have flourished, have given the eagle-owls a primary food source and allowed them occupy regions where they were once marginalized or absent.