B. (2009).  The other two slightly larger, tropical species possibly housed in a species complex with the long-eared owls were at one time considered to be part of the long-eared owls species.  During the period of courtship the male flies around and flaps its wing around, producing a clapping sound. Aschwanden, J., Birrer, S., & Jenni, L. (2005). Sekour, M., Baziz, B., Denys, C., Doumandji, S., Souttou, K., & Guezoul, O.  Ecological compensation areas (i.e.  A preference by long-eared owls for stands of conifers has been noted in many American studies. (2007). Leader, Z., Yom-Tov, Y., & Motro, U. Of the 51 fledged owls, 31 died in the study, 22 of which were due to mammal and bird predation, 6 due to starvation, 2 due to road collisions and 1 drowned in ditch. The genus name Asio is a type of eared owl, and otus also refers to a small, eared owl. Some normally young bird from central Europe migrate southwest at distances of up to more than 2,000 km (1,200 mi). In flight, tawny owls show well-fingered primaries (with five apparent emarginations) unlike the squared off wings of the long-eared owl. The print was engraved by Robert Havell in 1837.  Relatively large-sized prey, Indian gerbils (Tatera indica) and short-tailed bandicoot rats (Nesokia indica), was reported for wintering long-eared owls in Iran estimated to average 163 g (5.7 oz) and 155 g (5.5 oz), respectively, constituted a good portion of the prey (72.9% of biomass) and taken in almost even numbers with smaller Gerbillus species. Tian, L., Zhou, X., Shi, Y., Guo, Y., & Bao, W. (2015).  In Regional Park of Decima-Malafede, birds were 31.1% of the diet, 13.7% of which were unidentified passerines, while European goldfinches and European greenfinch accounted for a further 7.1% and 4.6% of the prey items.  Another regularly featured vole in the diet in America is the prairie vole (Microtus ochrogaster), but few other voles seem to be taken other than opportunistically excluding Oregon where the gray-tailed vole (Microtus canicaudus) and Townsend's vole (Microtus townsendii) locally led the foods. Bertolino, S., Ghiberti, E., & Perrone, A. In both western Russia and further east in western Siberia, the short-eared tended to take more tundra voles in addition to common voles, while long-eared owls focused more exclusively on common voles.  The highest densities may come from central Europe.  In the Sonian Forest, Belgium, 38.3% of 355 prey items were birds, mostly of various passerine species. In Europe, the mean estimated prey size overall was 32.2 g (1.14 oz). While diets are poorly researched in detail in Canada, in the northern tier states of Massachusetts, Michigan, Minnesota, Ohio, New York, Wisconsin and northern Oregon voles were easily the main prey for long-eared owls.  Once prey is spotted, the long-eared owl's flight suddenly stalls, then they quickly drop with talons spread to pounce on prey that is perceived, or especially, that comes out into the open. The tail may measure 121.5 to 161 mm (4.78 to 6.34 in) in males and 143.5 to 165 mm (5.65 to 6.50 in) in females, with 1408 owls averaging 146.3 mm (5.76 in).  Habitat may be perhaps even more key than prey numbers to the selection of hunting grounds. Cheveau, M., Drapeau, P., Imbeau, L., & Bergeron, Y. (2009).  Breeding success in this species is largely correlated with prey populations and predation risks.  As with many owls, all ages may produce hissing sounds and bill snapping when they feel threatened, especially in the context of nesting.  When flying by day, long-eared owls are often mobbed by diurnal birds such as corvids and other birds of prey. Capizzi, D., & Luigi Canou, P. V. (1998). During the display flight, the male may make as many as 20 claps. Females typically take on the duty of inspecting potential nesting sites and duets with its mate; perched on a chosen nest, she sings to contact the male, later vocal activity is confined to weak calls only heard at short range. Out of 86 prey studies in the continent, in about 69% voles made up more than half of the prey.  Much study has gone into contrasting the ecology of long-eared owls against other owls and also occasionally diurnal birds of prey, especially in terms of differences in dietary habits and habitat preferences.  However, the feeding niche tends to be much wider and more opportunistic in screech owls, which often feed on a diversity of invertebrates (mainly insects but also crayfish) and alternate prey (a higher balance of birds and frogs, for instance) and so are unlikely to competitively limit rodent numbers to the detriment of long-eared owls.  The reason for roosting in aggregations seems to be at least in part to mitigate predation risks. In the north, it is scarce to absent in areas of the deep boreal forest and the treeless northern areas such as around large wetland bogs or lower tundra, where the short-eared owl tends to supplant them. In …  More often than visually finding their prey, it is thought that long-eared owls most often audibly detect the rustling of their intended food.  West Nile virus and Salmonella has been the recorded source of mortality for some long-eared owls.  A study in Idaho determined that long-eared owls were locally extremely monogamous, with no extra-pair fertilizations were detected in 59 nestlings from 12 nests.  In the Venice area, of 642 prey items examined and a total prey mass of 15,038 g (33.153 lb), birds made up 38.47% by number and 41% of the biomass.  Many long-eared owls are also killed by road traffic. Long-eared Owls are sometimes considered resident throughout their breeding range, but it is likely that most birds do migrate, especially those in the northern part of their range. Roost height in the New Jersey study was at 3 to 15 m (9.8 to 49.2 ft) or occasionally higher. Tulis, F., Baláž, M., Obuch, J., & Šotnár, K. (2015).  Some biologists feel that long-eared owls tendency to avoid richer prey concentrations in favor of opener habitats and spatial usage, especially while migrating and wintering, is partial dictated by the detection of eagle-owl (and perhaps goshawk) activity, so therefore the eagle-owl has a serious influence on the long-eared owl's life history.