In the vicinity of Umbria in Italy, 47.8% of 874 prey items were invertebrates, particularly keelback slugs and roundback slugs, which together made up 28.6% of the prey items followed among invertebrates by Melolonthinae subfamily of scarab beetles at about 7% of the prey. (1993).  A female territorial call is somewhat like the male's but is hoarser, less clear and somewhat higher in pitch, transcribed as cher oooOOooo followed by chro cher-oooOOooo cooEEooooo.  Also around 12 days, the nestlings produce their first pellets, though they are often of a rather liquid consistency. Sánchez-Zapata, J.  Cambridgeshire produced an average of 0.3 for all territories in fragmented woods and 0.89 for all territories in continuous woods. Żmihorski, M., Gryz, J., Krauze-Gryz, D., Olczyk, A., & Osojca, G. (2011).  Unlike their larger, more powerful cousin, the Ural owl, the tawny owl is not infrequently vicim to predation by larger raptors. , Song posts are often only 250 to 300 m (820 to 980 ft) from their roost sites.  The tawny owl is also found throughout England and Scotland, but is not present in some of less well wooded areas of northern Scotland.  Caterpillars may too be taken from trees. Debén, S., Fernández, J. Á., Aboal, J. R., & Carballeira, A. The most important avian foods to English tawny owls were the house sparrow (at 27% and 52% in Wythenshawe and Holland Park), the common starling (Sturnus vulgaris) (at 33% in Wythenshawe) and the rock dove (at 22% in Holland Park). (2008). Neuhaus, W., Bretting, H., & Schweizer, B. Koning, F. J., Koning, H. J., & Baeyens, G. (2009).  A study within Spain recording only spontaneous vocalizations that only a low percentage of territories could be detected this way, about 12%, and that males spontaneously called about 2 to 4 times more frequently than females. This is part of their overall camouflage that allows them to easily blend into their surroundings.  Alternatively, this species may hunt from flight. Overskaug, K., Bolstad, J. P., Sunde, P., & ⵁien, I. J. This race is paler still than the nominate race with a large amount of dazzling white apparent on the sparsely marked underside, which tends to bare relatively few crossbars. , The species was first described by Carl Linnaeus in his landmark 1758 10th edition of Systema Naturae under its current scientific name.  In the UK it is on the RSPB Amber List of Concern. the Ural).  Among their known owl prey species are Eurasian scops owls (Otus scops), Eurasian pygmy owls, little owls (Athene noctua), long-eared owls and boreal owls (Aegolius funereus).  European pine martens are known to be a considerable threat of all aged tawny owls at nests from nestlings to brooding females, as are probably stone martens (Martes foina).  However, in much of mainland Europe and elsewhere, tawny owls potentially overlap with larger owls and, depending on habitat composition and prey accessibilities, may be considered more correctly a mesopredator. Freeman, S. N., Balmer, D. E., & Crick, H. Q.  The tawny owls has a comparable ear morphology to the Ural owl (Strix uralensis).  Undigested material coughed up often reveals different prey than pellets.  The mother owls are often tight sitters, one female sat motionless even as she was physically turned over, while another sat tight but flushed eventually after several human intrusions.  Although clutch sizes average smaller in Great Britain than in mainland Europe, they are more consistently laid there than the clutches of barn owls. The pellets are typically grey coloured and are found in groups under trees used for roosting or nesting.  A record in Bizkaia, Spain of a second successful clutch was produced, with pairs of owlets were recorded in February then another pair of owlets apparently hatched to the same pair was recorded in July of same year. Tawny Owl Strix aluco. (2000). Brooke, M. D. L., Hanley, S., & Laughlin, S. B.  In terms of peri-urbanisation, the long-eared and tawny owls are more or less equally adaptive to such areas. Heavier parents raised all offspring hatched to them, while lighter parents raised 33% of the offspring. In Danish owls, weights were lowest during brooding and fledgling stages and highest in winter, varying up to 12% and 10%, respectively, in males and females.  The calls of tawny owls are easily imitated by blowing into cupped hands through slightly parted thumbs, and a study in Cambridgeshire found that this mimicry produced a response from the owl within 30 minutes in 94% of trials.  They can appear to be a heavy flier but are capable of surprising maneuverability within woods, flying with utter silence.  In England, it was estimated that there was 6-11 times lower survival rate for tawny owls that were ragiotagged than for those that were not based on estimates, the theory as to why it lower survival is that the additional weight burden of the radio-tags themselves may have inhibited capture of food and also made juveniles more vulnerable to goshawks.  The diameter of the eye reaches about 16 to 23 mm (0.63 to 0.91 in), against 11 mm (0.43 in) in the long-eared owl, while the tawny's axial length reaches 29 to 35.7 mm (1.14 to 1.41 in). Irrespective of nest type, young Tawnies usually leave the nest for good at around 3-4 weeks of age, a phase known as ‘branching’. The tawny owl’s head is also slightly larger. , In the largest known European diet studies, rodents usually are predominant. , Helminths are also fairly common and may compromise the condition of many owls, if rarely the cause of direct fatalities. 73.7% of the studied French broods produced fledglings. The tawny owl is an opportunistic and generalized predator. the Kampinos Forest) outside the urbanized areas of Warsaw, other prey such as rodents and frogs were favored instead.  While in Bohemia, the clutch size varied remarkably little by year, in western Switzerland it could go from 2.52 to 3.63 in different years and Finnish data indicates it can vary from 3.1 to 4.2 in low and peak vole years. & Marks, J.S. Egg dimensions were found to average 46.7 mm × 39.1 mm (1.84 in × 1.54 in) in Britain, 47.6 mm × 39.2 mm (1.87 in × 1.54 in) in central Europe, 46.6 mm × 38.5 mm (1.83 in × 1.52 in) in Sweden (Makatsch 1976) and 47.5 mm × 39.2 mm (1.87 in × 1.54 in) in Russia.  The hunting owl often extends its wings to balance and control prey upon impact. The tawny owl is a member of the genus Strix, that is also the origin of the family's name under Linnaean taxonomy. In the Belgian data, of 195 young hatched, 94% fledged and 6% died in nest as a result of starvation, with an average number of fledglings 2.06, varying from 0 to 3.25 on average in different years based on vole numbers. After another gap, the range resumes in northeasternmost Afghanistan, northern Pakistan, eastern Tajikistan and north India (mostly western Jammu and Kashmir).  In the German area of Swabian Jura clutches may start to be laid as early as mid-February if food is favorable. , Plumage coloring in this species can be very variable. Marchesi, L., Sergio, F., & Pedrini, P. (2006). Grey, brown and rufous morphs exist, as well as intermediate birds.  Although moderately hardy during sub-freezing winters, severe winters can be dangerous in areas such as the Russian part of their range.  In Sahel, Algeria, invertebrates in total slightly outnumbered mammals, but lagged slightly behind birds in number. Usually, the often fairly drowsy owls are unable to counterattack or kill their wary tormentors and may at times depart and try to seek out another roost.  Another species even more recently found to be distinct from tawny owls is the little-known Himalayan owl (Strix nivicolum).  Natural holes in trees are often the most frequently used nesting site, followed closely in recent decades many artificial nest boxes, preferably those with a 15 cm × 20 cm (5.9 in × 7.9 in) entrance or larger. Both countries have healthy recovered populations of eagle-owls, so tawny owls appear to locally restrict their vocal activity and tend to occur on the fringes or outside active eagle-owl ranges.  While most bats encountered (and hunted) are fairly small-bodied, tawny owls may hunt bats of all sizes available, from the roughly 4 g (0.14 oz) common pipistrelle (Pipistrellus pipistrellus) to the 59 g (2.1 oz) greater noctule (Nyctalus lasiopterus) in Europe and to the 140 g (4.9 oz) Egyptian fruit bat (Rousettus aegyptiacus) outside of Europe.