Listen to this article

Tawny owl

From Wikipedia, the free encyclopedia
  (Redirected from Strix aluco)
Jump to navigation Jump to search
"Brown owl" redirects here. For other uses, see Brown owl (disambiguation).

Tawny owl
Strix aluco 3 (Martin Mecnarowski).jpg
Grey morph individual
Hooting song, UK
Scientific classification edit
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Strigiformes
Family: Strigidae
Genus: Strix
Species:
S. aluco
Binomial name
Strix aluco
Strix aluco distribution map.png
Synonyms

Strix stridula Linnaeus, 1758

The tawny owl or brown owl (Strix aluco) is a stocky, medium-sized owl commonly found in woodlands across much of Eurasia and North Africa. Its underparts are pale with dark streaks, and the upperparts are either brown or grey. Several of the eleven recognised subspecies have both variants. The nest is typically in a tree hole where it can protect its eggs and young against potential predators. This owl is non-migratory and highly territorial. Many young birds starve if they cannot find a vacant territory once parental care ceases.

This nocturnal bird of prey hunts mainly rodents, usually by dropping from a perch to seize its prey, which it swallows whole; in more urban areas its diet includes a higher proportion of birds. Vision and hearing adaptations and silent flight aid its night hunting. The tawny owl is capable of catching smaller owls, but is itself vulnerable to the eagle owl or northern goshawk.

Although many people believe this owl has exceptional night vision, its retina is no more sensitive than a human's and its asymmetrically placed ears are key to its hunting by giving it excellent directional hearing. Its nocturnal habits and eerie, easily imitated call, have led to a mythical association of the tawny owl with bad luck and death. In addition, the common onomatopoeia for an owl hooting is derived from the calls of this species; the complete sound is actually a duet between a male and a female.[2][3]

Description[edit]

A composite image of the western subspecies S. a. sylvatica, for identification.

The tawny owl is a robust bird, 37–46 cm (15–18 in) in length, with an 81–105 cm (32–41 in) wingspan. Weight can range from 385 to 800 g (0.849 to 1.764 lb).[4][5] Its large rounded head lacks ear tufts, and the facial disc surrounding the dark brown eyes is usually rather plain. The nominate race has two morphs which differ in their plumage colour, one form having rufous brown upperparts and the other greyish brown, although intermediates also occur. The underparts of both morphs are whitish and streaked with brown.[6] Feathers are moulted gradually between June and December.[7] This species is sexually dimorphic; the female is much larger than the male, 5% longer and more than 25% heavier.[8]

The tawny owl flies with long glides on rounded wings, less undulating and with fewer wingbeats than other Eurasian owls, and typically at a greater height. The flight of the tawny owl is rather heavy and slow, particularly at takeoff.[9] As with most owls, its flight is silent because of its feathers' soft, furry upper surfaces and a fringe on the leading edge of the outer primaries.[10] Its size, squat shape and broad wings distinguish it from other owls found within its range; great grey, eagle and Ural owls are similar in shape, but much larger.[9]

An owl's eyes are placed at the front of the head and have a field overlap of 50–70%, giving it better binocular vision than diurnal birds of prey (overlap 30–50%).[11] The tawny owl's retina has about 56,000 light-sensitive rod cells per square millimetre (36 million per square inch); although earlier claims that it could see in the infrared part of the spectrum have been dismissed,[12] it is still often said to have eyesight 10 to 100 times better than humans in low-light conditions. However, the experimental basis for this claim is probably inaccurate by at least a factor of 10.[13] The owl's actual visual acuity is only slightly greater than that of humans, and any increased sensitivity is due to optical factors rather than to greater retinal sensitivity; both humans and owl have reached the limit of resolution for the retinas of terrestrial vertebrates.[13]

Adaptations to night vision include the large size of the eye, its tubular shape, large numbers of closely packed retinal rods, and an absence of cone cells, since rod cells have superior light sensitivity. There are few coloured oil drops, which would reduce the light intensity.[14] Unlike diurnal birds of prey, owls normally have only one fovea, and that is poorly developed except in daytime hunters like the short-eared owl.[11]

Hearing is important for a nocturnal bird of prey, and as with other owls, the tawny owl's two ear openings differ in structure and are asymmetrically placed to improve directional hearing. A passage through the skull links the eardrums, and small differences in the time of arrival of a sound at each ear enables its source to be pinpointed. The left ear opening is higher on the head than the larger right ear and tilts downward, improving sensitivity to sounds from below.[11] Both ear openings are hidden under the facial disk feathers, which are structurally specialized to be transparent to sound, and are supported by a movable fold of skin (the pre-aural flap).[15]

An owl's retina has a single fovea.[16]

The internal structure of the ear, which has large numbers of auditory neurons, gives an improved ability to detect low-frequency sounds at a distance, which could include rustling made by prey moving in vegetation.[15] The tawny owl's hearing is ten times better than a human's,[15] and it can hunt using this sense alone in the dark of a woodland on an overcast night, but the patter of raindrops makes it difficult to detect faint sounds, and prolonged wet weather can lead to starvation if the owl cannot hunt effectively.[11]

Hooting song, Gloucestershire, England, 1978
'Kewick' calls, England, 1960s

The commonly heard female contact call is a shrill, kew-wick but the male has a quavering advertising song hoo...ho, ho, hoo-hoo-hoo-hoo. William Shakespeare used this owl's song in Love's Labour's Lost (Act 5, Scene 2) as "Then nightly sings the staring owl, Tu-whit; Tu-who, a merry note, While greasy Joan doth keel the pot", but this stereotypical call is actually a duet, with the female making the kew-wick sound, and the male responding hooo.[6] The call is 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.[17] A male's response to a broadcast song appears to be indicative of his health and vigour; owls with higher blood parasite loads use fewer high frequencies and a more limited range of frequencies in their responses to an apparent intruder.[18] The vocal activity of tawny owls depends on sex, annual cycle stage and weather, with males being more vocal than females year-round, with peak vocal activity during incubation and post-breeding.[19]

Geographical variation[edit]

Although both colour morphs occur in much of the European range, brown birds predominate in the more humid climate of western Europe, with the grey morph becoming more common further east; in the northernmost regions, all the owls are a cold-grey colour. Siberian and Central Asian subspecies have grey and white plumage, the North African race is dark grey-brown, and South and East Asian birds have barred, not striped, underparts, and fine lines around the facial disc. The Siberian and Scandinavian subspecies are 12% larger and 40% heavier, and have 13% longer wings than western European birds,[15] in accordance with Bergmann's rule which predicts that northern forms will typically be bigger than their southern counterparts.[20]

The plumage colour is genetically controlled, and studies in Finland and Italy indicate that grey-morph tawny owls have more reproductive success, better immune resistance, and fewer parasites than brown birds. Although this might suggest that eventually the brown morph could disappear, the owls show no colour preference when choosing a mate, so the selection pressure in favour of the grey morph is reduced. There are also environmental factors involved. The Italian study showed that brown-morph birds were found in denser woodland, and in Finland, Gloger's rule would suggest that paler birds would in any case predominate in the colder climate.[21][22]

Taxonomy[edit]

Main article: Taxonomy of the tawny owl

The species was first described by Linnaeus in his Systema naturae in 1758 under its current scientific name.[23] The binomial derives from Greek strix "owl" and Italian allocco, "tawny owl" (from Latin ulucus "screech-owl").[8]

Individual from France perched upon a human hand

The tawny owl is a member of the wood-owl genus Strix, part of the typical owl family Strigidae, which contains all species of owl other than the barn owls. Within its genus, the tawny owl's closest relatives are Hume's owl, Strix butleri, (formerly considered to be conspecific), the Himalayan owl, Strix nivicolum, (sometimes considered conspecific), its larger northern neighbour, the Ural owl, S. uralensis, and the North American barred owl, S. varia.[15] The Early–Middle Pleistocene Strix intermedia is sometimes considered a paleosubspecies of the tawny owl, which would make it that species' immediate ancestor.[24]

The tawny owl subspecies are often poorly differentiated, and may be at a flexible stage of subspecies formation with features related to the ambient temperature, the colour tone of the local habitat, and the size of available prey. Consequently, various authors have historically described between 10 and 15 subspecies.[15] The currently recognised subspecies are listed below.[25]

Subspecies Range Described by (parentheses indicate originally in a different genus)
S. a. aluco N & C Europe from Scandinavia to the Mediterranean and Black Sea Linnaeus, 1758
S. a. sylvatica W Europe including Great Britain Shaw, 1809
S. a. biddulphi NW India and Pakistan Scully, 1881
S. a. willkonskii Palestine to N Iran and the Caucasus (Menzbier, 1896)
S. a. mauritanica NW Africa from Morocco to Tunisia and Mauritania (Witherby, 1905)
S. a. sanctinicolai W Iran, NE Iraq (Zarudny, 1905)
S. a. harmsi Turkmenyia (Zarudny, 1911)
S. a. siberiae C Russia from Urals to W Siberia Dementiev, 1933
S. a. nivicola Nepal to SE china, South to N Myanmar (Burma) and Thailand
S. a. yamadae Taiwan
S. a. ma NE China and Korea

Distribution and habitat[edit]

Ancient deciduous woodland is a favoured habitat

The tawny owl has a distribution stretching discontinuously across temperate Eurasia from Great Britain and the Iberian Peninsula eastwards to western Siberia. The subspecies S. a. mauritanica extends the range into northwest Africa. This essentially non-migratory owl is absent from Ireland (probably because of competition from the long-eared owl), and only a rare vagrant to the Balearic and Canary Islands.[9]

This species is found in deciduous and mixed forests, and sometimes mature conifer plantations, preferring locations with access to water. Cemeteries, gardens and parks have allowed it to spread into urban areas, including central London. Although tawny owls occur in urban environments, especially those with natural forests and wooded habitat patches, they are less likely to occur at sites with high noise levels at night.[26] The tawny owl is mainly a lowland bird in the colder parts of its range, but breeds to 550 metres (1,800 ft) in Scotland, 1,600 m (5,200 ft) in the Alps, 2,350 m (7,710 ft) in Turkey,[9] and up to 2,800 m (9,200 ft) in Myanmar.[15]

The tawny owl has a geographical range of at least 10 million km2 (3.8 million mi2) and a large population including an estimated 970,000–2,000,000 individuals in Europe alone. Population trends have not been quantified, but there is evidence of an overall increase. This owl is not believed to meet the IUCN Red List criterion of declining more than 30% in ten years or three generations and is therefore evaluated as being of least concern.[1] In the UK it is on the RSPB Amber List of Concern.[27] This species has expanded its range in Belgium, the Netherlands, Norway and Ukraine, and populations are stable or increasing in most European countries. Declines have occurred in Finland, Estonia, Italy and Albania.[9]

Behaviour[edit]

Breeding[edit]

Main article: Breeding biology of the tawny owl
Tawny owls are quite nocturnal
Young leave the nest before fledging
Strix aluco sylvatica - MHNT

Tawny owls pair off from the age of one year, and stay together in a usually monogamous relationship for life. An established pair's territory is defended year-round and maintained with little, if any, boundary change from year to year. The pair sit in cover on a branch close to a tree trunk during the day, and usually roost separately from July to October.[9] Roosting owls may be discovered and "mobbed" by small birds during the day, but they normally ignore the disturbance.[15]

The tawny owl typically nests in a hole in a tree, but will also use old European magpie nests, squirrel drey or holes in buildings, and readily takes to nest boxes. It nests from February onwards in the south of its range, but rarely before mid-March in Scandinavia.[9] The glossy white eggs are 48 mm × 39 mm (1.9 in × 1.5 in) in size and weigh 39.0 g (1.38 oz) of which 7% is shell. The typical clutch of two or three eggs is incubated by the female alone for 30 days to hatching, and the altricial, downy chicks fledge in a further 35–39 days.[8] The young usually leave the nest up to ten days before fledging, and hide on nearby branches.[9]

This species is fearless in defence of its nest and young, and, like other Strix owls, strikes for the intruder's head with its sharp talons. Because its flight is silent, it may not be detected until it is too late to avoid the danger. Dogs, cats and humans may be assaulted, sometimes without provocation.[15] Perhaps the best-known victim of the tawny owl's fierce attack was the renowned bird photographer Eric Hosking, who lost his left eye when struck by a bird he was attempting to photograph near its nest in 1937. He later called his autobiography An Eye for a Bird.[28]

The parents care for young birds for two or three months after they fledge, but from August to November the juveniles disperse to find a territory of their own to occupy. If they fail to find a vacant territory, they usually starve.[9] The juvenile survival rate is unknown, but the annual survival rate for adults is 76.8%. The typical lifespan is five years,[8] but an age of over 18 years has been recorded for a wild tawny owl, and of over 27 years for a captive bird.[15]

Predators of the tawny owl include large birds such as Ural owls, eagle owls, northern goshawks, golden eagles, and common buzzards. Pine martens may raid nests, especially where artificial nest boxes make the owls easy to find, and several instances have been recorded of Eurasian jackdaws building nests on top of a brooding female tawny owl leading to the death of the adult and chicks.[15] A Danish study showed that predation by mammals, especially red foxes, was an important cause of mortality in newly fledged young, with 36% dying between fledging and independence. The mortality risk increased with fledging date from 14% in April to more than 58% in June, and increasing predation of late broods may be an important selective agent for early breeding in this species.[29]

This species is increasingly affected by avian malaria, the incidence of which has tripled in the last 70 years, in parallel with increasing global temperatures. An increase of one degree Celsius produces a two- to three-fold increase in the rate of malaria. In 2010, the incidence in British tawny owls was 60%, compared to 2–3% in 1996.[30]

Feeding[edit]

Main article: Dietary biology of the tawny owl
Bank vole is a common prey

The tawny owl hunts almost entirely at night, watching from a perch before dropping or gliding silently down to its victim, but very occasionally it will hunt in daylight when it has young to feed. This species takes a wide range of prey, mainly woodland rodents, but also other mammals up to the size of a young rabbit, and birds, earthworms and beetles. In urban areas, birds make up a larger proportion of the diet, and species as unlikely as mallard and kittiwake have been killed and eaten.[9]

Prey is typically swallowed whole, with indigestible parts regurgitated as pellets. These are medium-sized and grey, consisting mainly of rodent fur and often with bones protruding, and are found in groups under trees used for roosting or nesting.[10]

Less powerful woodland owls such as the little owl and the long-eared owl cannot usually co-exist with the stronger tawny owls, which may take them as food items, and are found in different habitats; in Ireland the absence of the tawny owl allowed the long-eared owl to become the dominant owl. Similarly, where the tawny owl has moved into built-up areas, it tends to displace barn owls from their traditional nesting sites in buildings.[15]

Parasitism and bacterial infections[edit]

Helminths are also fairly common and may compromise the condition of many owls, if rarely the cause of direct fatalities.[31] Parasites commonly recorded in tawny owls including Leucocytozoon, Haemoproteus, Toxoplasma, Trypanosoma, Centrorhynchus and Tetrameres, with different species of Leucocytozoon present in about 95% of 32 individuals in Great Britain and 57% of study specimens in Italy.[9][32][33][34] Haemoptroteus was the prevalent parasites in France and also quite prominent in birds from Turkey.[35][36] The first records of Trichinella were recorded recently in Europe as well as the similarly rare Eimeria.[37][38] Blood parasitism was more common in England when food supplies were lowered.[39][40] In some cases, parasites are contracted directly from their prey.[41] It was estimated that about 25% of free-living adults in England had some variety of ocular lesions, which may lead to cases of bacterial infections and conjunctiva.[42] Concentrations of Enterobacteriaceae, which can be fatal to humans, are sometimes found in nest boxes.[43]

Conservation[edit]

The tawny owl is a common bird, especially in central Europe.[44][45] A mid-1990s estimate of the European population was 400,000-800,000 pairs.[9] The tawny owl has a geographical range of at least 10 million km2 (3.8 million mi2) and a large population including an estimated 970,000–2,000,000 individuals in Europe alone with more extensive surveys two decades later.[1][46] Population trends have not been quantified, but there is evidence of an overall increase. This owl is not believed to meet the IUCN Red List criterion of declining more than 30% in ten years or three generations and is therefore evaluated as being of least concern.[1][46] Globally, the population may be estimated anywhere from 1 million to nearly 3 million individuals.[1] 50% of European numbers were in the nations of Germany, France, Poland, Italy and Russia.[9][46] In the UK it is on the RSPB Amber List of Concern.[47] In Great Britain, estimated number there in the 1970s ran up to 100,000 pairs whereas more recent estimate suggest much fewer, at about 20,000 pairs.[46] Although estimates are variable, close study has shown a population reduction of fairly nebulous cause in Britain of around 11% from 1968-1972 to 1988-1991 or of an estimated 6% from 1970 to 2010, utilizing two different surveying methods.[48][49][50] Relative to the loss of other British woodland birds, which has been pronounced, the tawny owl reductions may be considered small to moderate. Among myriad and complex causes for all forest birds in Britain, for the tawny owl it is mentioned that competition for nest sites with introduced eastern gray squirrels (Sciurus carolinensis) may be responsible for some of the reductions.[51] The French population of tawny owls is very large and increased in estimated numbers from 10,000-100,000 in the early 1970s to 50,000-150,000 estimated in the 1990s.[9] 5 digit numbers are estimated in many European countries, including Germany, Italy, Poland, Norway, Sweden, Spain, Greece, Croatia, European Russia and Belarus.[9] It is thought that declines may have occurred in Finland, Estonia, Albania and even Italy.[52] The estimated number of breeding pairs within Denmark using different calculation methods was very variable with different estimates from 4800 to 7400 to 20,500.[53] A large number were estimated in Turkey, perhaps up to an estimated 25,000 pairs, with Syria estimated up to 50 pairs and 250 pairs roughly in Israel.[1][9] While tawny owls may commonly use nest boxes, these are not considered necessary given the general stability of the population.[44] Increased populations pose a risk to smaller owls in areas of sympatry and may hamper conservation efforts of such species.[44]

Besides natural causes such as predation and starvation, collision with vehicles, power lines, any other kind of wire collision and other manmade objects is a regular cause of tawny owl mortality.[9][54] Occasionally, the species is exposed to assorted forms of human persecution (from egg-collecting to shootings and poisonings) but it is not nearly as extensively persecuted as larger birds like golden eagles, goshawks and eagle owls. However, earlier in the 20th century, as many as 12% of birds recovered in Scandinavia were dead from various forms of persecution.[15][55][56] Although they are fairly adaptable to urbanization, there are limits to the tawny owls adaptability, especially due to declines in woodland quality, prey access and human-sourced mortality sources, one of the worst of which is collision with vehicles.[9][57] Of 112 tawny owls re-released in the wild from England's East Winch Wildlife Centre, 17% were subsequently recovered (about half of which were dead), with the most diagnosed cause of mishap being road accidents.[58] Of 57 tawny owls released in Somerset and Hampshire, 28% were recovered dead.[59] However, tawny owls, perhaps due to their liking of wooded rather open areas, are relatively less vulnerable to automobile deaths than some other owls, i.e. of hundreds dead owls on roadsides in Italy, only 4.5% were tawnys, while 41% were little owls and 39% barn owls, while in Germany, 7.4% were tawnys, against 53% barn owls and 28.4% little owls.[60] Variable levels of occular damage, with comparable levels of ocular trauma to humans who are victims of car collisions, were detected in 50 tawny owls in England recovered after surviving car collisions.[61] Damage to the occular area was recorded in 128 of 216 free-living tawnys in southwest England, and in 60.5% of 147 admitted birds the injury were due to road accidents.[62] In the forest of Burgundy, road-based deaths were the main cause of mortality that could be diagnosed.[63] Roadkills of tawny owls were fairly frequent in Portugal, but were not usually in prime habitat and often occurred near the borders of existing territories.[64] However, density was reduced by road development in Portuguese owls, largely due to the fragmentation of habitat, disturbance and noise pollution that may effect intraspecific communication and hunting and increase mortality may come with major roads for owls.[65] Similarly, in Germany, despite the general adaptability to development in tawny owls, locally the noise pollution and increased fragmentation of woods was found to be reducing tawny owl populations.[66] An unclear number of tawny owls may be killed by heavy metal contamination via bioaccumulation as well as via pesticide use.[44][67] Lead levels were difficult to estimate in Spanish owls due to the large number of feathers needed to estimate them, while dead Spanish owls had middling, variable levels of mercury concentrations.[68][69][70] In eggs from Norway, polyfluoroalkyl compounds were studied, in sum toxicological implications were low and several times lower than would be implied by the diversity of compounds found in the eggs.[71] British birds appear to be effected by second-generation anticoagulants, with about 20% of 192 birds showing detectable residues of these. The number is lower than other raptors analysed here such as common kestrel, barn owl, common buzzard and red kite and the number of tawnys did not perceptibly decline due to this.[72] In Sweden and perhaps Germany, the level of PFAS and mercury were fairly low, comparable to common kestrel and much lower than the levels in ospreys (Pandion haliaetus).[73][74]

In culture[edit]

Grey individual, probably subspecies S. a. aluco

The tawny owl, like its relatives, has often been seen as an omen of bad luck; William Shakespeare used it as such in Julius Caesar (Act 1 Scene 3): "And yesterday the bird of night did sit/ Even at noon-day upon the market-place/ Hooting and shrieking." John Ruskin is quoted as saying "Whatever wise people may say of them, I at least have found the owl's cry always prophetic of mischief to me".[75]

Wordsworth described the technique for calling an owl in his poem There was a Boy.[76]

And there, with fingers interwoven, both hands
Pressed closely palm to palm and to his mouth
Uplifted, he, as through an instrument,
Blew mimic hootings to the silent owls,
That they might answer him.—And they would shout
Across the watery vale, and shout again,
Responsive to his call,—with quivering peals,
And long halloos, and screams, and echoes loud
Redoubled and redoubled; concourse wild
Of jocund din!

References[edit]

  1. ^ a b c d e f BirdLife International (2016). "Strix aluco". IUCN Red List of Threatened Species. 2016: e.T22725469A86871093. doi:10.2305/IUCN.UK.2016-3.RLTS.T22725469A86871093.en. Retrieved 19 November 2021.
  2. ^ "Tawny owl | The Wildlife Trusts". www.wildlifetrusts.org. Retrieved 2021-06-24.
  3. ^ "Tawny owl guide: how to identify, diet and where to see". Discover Wildlife. Retrieved 2021-06-24.
  4. ^ CRC Handbook of Avian Body Masses by John B. Dunning Jr. (Editor). CRC Press (1992), ISBN 978-0-8493-4258-5.
  5. ^ Eurasian Tawny Owl – Strix aluco. The Owl Pages
  6. ^ a b Mullarney, Killian; Svensson, Lars; Zetterstrom, Dan; Grant, Peter J. (1999). Collins Bird Guide. London: HarperCollins. p. 206. ISBN 978-0-00-219728-1.
  7. ^ RSPB Handbook of British Birds (2014). ISBN 978-1-4729-0647-2.
  8. ^ a b c d "Tawny Owl Strix aluco [Linnaeus, 1758]". BirdFacts. British Trust for Ornithology (BTO). Retrieved 31 May 2008.
  9. ^ a b c d e f g h i j k l m n o p q r Snow, David (1998). Perrins, Christopher M. (ed.). The Birds of the Western Palearctic concise edition (two volumes). Oxford: Oxford University Press. pp. 907–910. ISBN 978-0-19-854099-1.
  10. ^ a b Brown, Roy; Ferguson, John; Lawrence, Michael; Lees, David (1987). Tracks and Signs of the Birds of Britain and Europe (Helm Identification Guides). Christopher Helm. p. 86. ISBN 978-0-7470-0201-7.
  11. ^ a b c d Burton, Robert (1985). Bird Behaviour. London: Granada Publishing. pp. 44–48. ISBN 978-0-246-12440-1.
  12. ^ Hecht, Selig; Pirenne, Maurice Henri (1940). "The sensibility of the nocturnal long-eared owl in the spectrum". Journal of General Physiology. 23 (6): 709–717. doi:10.1085/jgp.23.6.709. PMC 2237955. PMID 19873186.
  13. ^ a b Martin, Graham R. (August 1977). "Absolute visual threshold and scotopic spectral sensitivity in the tawny owl Strix aluco". Nature. 268 (5621): 636–638. Bibcode:1977Natur.268..636M. doi:10.1038/268636a0. PMID 895859. S2CID 4184444.
  14. ^ Sinclair, Sandra (1985). How Animals See: Other Visions of Our World. Beckenham, Kent: Croom Helm. pp. 88–100. ISBN 978-0-7099-3336-6.
  15. ^ a b c d e f g h i j k l m Voous, Karel H.; Cameron, Ad (illustrator) (1988). Owls of the Northern Hemisphere. London, Collins. pp. 209–219. ISBN 978-0-00-219493-8.
  16. ^ Based on Güntürkün, Onur, "Structure and functions of the eye" in Sturkie, P. D. (1998). Sturkie's Avian Physiology. 5th Edition. Academic Press, San Diego. pp. 1–18. ISBN 978-0-12-747605-6.
  17. ^ Redpath, S. M. (1994). "Censusing Tawny Owls Strix aluco by the use of imitation calls". Bird Study. 41 (3): 192–198. doi:10.1080/00063659409477219.
  18. ^ Redpath, Stephen M.; Appleby, Bridget M.; Petty, Steve J. (2000). "Do male hoots betray parasite loads in Tawny Owls?". Journal of Avian Biology. 31 (4): 457–462. doi:10.1034/j.1600-048X.2000.310404.x.
  19. ^ Zuberogoitia, I.; Burgos, G.; González‐Oreja, J.A.; Morant, J.; Martínez, J.E.; Albizua, J.Z. (2019). "Factors affecting spontaneous vocal activity of Tawny Owls Strix aluco and implications for surveying large areas". Ibis. 161 (3): 495–503. doi:10.1111/ibi.12684.
  20. ^ Bergmann, Carl (1847). "Über die Verhältnisse der Wärmeökonomie der Thiere zu ihrer Grösse". Göttinger Studien (in German). 3 (1): 595–708.
  21. ^ Brommer, Jon E.; Kari, Ahola; Karstinen, Teuvo (2005). "The colour of fitness: plumage coloration and lifetime reproductive success in the tawny owl". Proceedings of the Royal Society of London B: Biological Sciences. 272 (1566): 935–940. doi:10.1098/rspb.2005.3052. PMC 1564093. PMID 16024349.
  22. ^ Galeotti, Paolo; Sacchi, Roberto (2003). "Differential parasitaemia in the SNOWY OWLS ®(Strix aluco): effects of colour morph and habitat". Journal of Zoology. 261: 91–99. doi:10.1017/S0952836903003960.
  23. ^ Linnaeus, C (1758). Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata (in Latin). Holmiae. (Laurentii Salvii). p. 93. S. capite laevi, corpore ferrugineo, iridíbus atris, remi-gibus primoribus serratís.
  24. ^ (in German) Jánossy D. (1972) "Die mittelpleistozäne Vogelfauna der Stránská skála". In: Musil R. (ed.): "Stránská skála I." Anthropos (Brno) 20: 35–64.
  25. ^ "Tawny Owl Strix aluco". Owl Information. World Owl Trust. Archived from the original on 13 June 2008. Retrieved 7 November 2017.
  26. ^ Fröhlich, A.; Ciach, M. (2018). "Noise pollution and decreased size of wooded areas reduces the probability of occurrence of Tawny Owl Strix aluco". Ibis. 160 (3): 634–646. doi:10.1111/ibi.12554.
  27. ^ "RSPB Red Amber & Green List". RSPB Red Amber & Green Lists Explained. Royal Society for the Protection of Birds. Retrieved 10 December 2017.
  28. ^ Hosking, Eric; Lane, Frank W. (1972). An Eye for a Bird: The Autobiography of a Bird Photographer. London, Hutchinson & Co. p. 20. ISBN 978-0-09-104460-2.
  29. ^ Sunde, Peter (September 2005). "Predators control post-fledging mortality in tawny owls, Strix aluco". Oikos. 110 (3): 461–472. doi:10.1111/j.0030-1299.2005.14069.x.
  30. ^ GaramszegI, László Z. (2011). "Climate change increases the risk of malaria in birds". Global Change Biology. 17 (5): 1751–1759. Bibcode:2011GCBio..17.1751G. doi:10.1111/j.1365-2486.2010.02346.x.
  31. ^ Ewald, J. A., & Crompton, D. W. T. (1993). Centrorhynchus aluconis (Acanthocephala) and other helminth species in tawny owls (Strix aluco) in Great Britain. The Journal of parasitology, 952-954.
  32. ^ Couper, D., & Gibbons, L. M. (2010). Tetrameres species parasites in tawny owls (Strix aluco).
  33. ^ Aubert, D., Terrier, M. E., Dumètre, A., Barrat, J., & Villena, I. (2008). Prevalence of Toxoplasma gondii in raptors from France. Journal of wildlife diseases, 44(1), 172-173.
  34. ^ Baylis, H. A. (1939). XXXVIII.—Further records of parasitic worms from British vertebrates. Journal of Natural History, 4(23), 473-498.
  35. ^ Karadjian, G., Puech, M. P., Duval, L., Chavatte, J. M., Snounou, G., & Landau, I. (2013). Haemoproteus syrnii in Strix aluco from France: morphology, stages of sporogony in a hippoboscid fly, molecular characterization and discussion on the identification of Haemoproteus species. Parasite, 20.
  36. ^ Yildirim, A., Aysul, N., Bayramli, G., Inci, A., Eren, H., Aypak, S., Duzlu, O., Ciloglu, A. & Onder, Z. (2013). Detection and molecular characterization of a Haemoproteus lineage in a Tawny Owl (Strix aluco) in Turkey. Vet J Ankara Univ, 69, 179-183.
  37. ^ Hurnikova, Z., Hrčková, G., Ågren, E., Komorová, P., Forsman, J., Chovancová, B., & Letková, V. (2014). First finding of Trichinella pseudospiralis in two Tawny Owls (Strix aluco) from Sweden. Helminthologia, 51(3), 190-197.
  38. ^ Kolářová, I. (1982). First record of Eimeria strigis Kutzer, 1963 from tawny owl Strix aluco L. in Czechoslovakia. Folia Parasitologica, 29(4).
  39. ^ Appleby, B. M., Anwar, M. A., & Petty, S. J. (1999). Short‐term and long‐term effects of food supply on parasite burdens in Tawny Owls, Strix aluco. Functional Ecology, 13(3), 315-321.
  40. ^ McInnes, F. J., Crompton, D. W. T., & Ewald, J. A. (1994). The Distribution of Centrorhynchus aluconis (Acanthocephala) and Porrocaecum spirale (Nematoda) in Tawny Owls (Strix aluco) from Great Britain. Journal of Raptor Research, 28(1), 34-38.
  41. ^ Tadros, W., & Laarman, J. J. (1980, January). The Tawny Owl, Strix aluco, as final host of a new species of Sarcocystis with Mus musculus as intermediate. In Tropical and Geographical Medicine (Vol. 32, No. 4, pp. 364-364). C/O Royal Tropical Inst, Kit Press, Mauritskade 63, 1092 Ad Amsterdam, Netherlands: Tropical Geographical Medicine.
  42. ^ Cousquer, G. O., Cooper, J. E., & Cobb, M. A. (2010). Conjunctival flora in tawny owls (Strix aluco).
  43. ^ Grzywaczewski, G., Kowalczyk-Pecka, D., Cios, S., Bojar, W., Jankuszew, A., Bojar, H., & Kolejko, M. (2017). Tawny owl Strix aluco as a potential transmitter of Enterobacteriaceae epidemiologically relevant for forest service workers, nature protection service and ornithologists. Annals of Agricultural and Environmental Medicine, 24(1), 62-65.
  44. ^ a b c d König, Claus; Weick, Friedhelm (2008). Owls of the World (2nd ed.). London: Christopher Helm. ISBN 9781408108840.
  45. ^ Weick, Friedhelm (2007). Owls (Strigiformes): Annotated and Illustrated Checklist. Springer. ISBN 978-3-540-39567-6.
  46. ^ a b c d Petty, S. J., & Saurola, P. (1997). Strix aluco: Tawny Owl. The EBCC atlas of European breeding birds: their distribution and abundance. London: Poyser.
  47. ^ "RSPB Red Amber & Green List". RSPB Red Amber & Green Lists Explained. Royal Society for the Protection of Birds. Retrieved 10 December 2017.
  48. ^ Freeman, S. N., Balmer, D. E., & Crick, H. Q. (2006). On the censusing of Tawny Owl Strix aluco. Bird Census News, 19(2), 58-62.
  49. ^ Worthington-Hill, J., & Conway, G. (2017). Tawny Owl Strix aluco response to call-broadcasting and implications for survey design. Bird Study, 64(2), 205-210.
  50. ^ Percival, S. M. (1990). Population Trends in British Barn Owls, Tyto Alba, and Tawny Owls Strix Aluco, in Relation to Environmental Change. British Trust for Ornithology.
  51. ^ Fuller, R. J., Noble, D. G., Smith, K. W., & Vanhinsbergh, D. (2005). Recent declines in populations of woodland birds in Britain. British Birds, 98, 116-143.
  52. ^ Snow, David (1998). Perrins, Christopher M. (ed.). The Birds of the Western Palearctic concise edition (two volumes). Oxford: Oxford University Press. pp. 907–910. ISBN 978-0-19-854099-1.
  53. ^ Jensen, R. A., Sunde, P., & Nachman, G. (2012). Predicting the distribution of Tawny Owl (Strix aluco) at the scale of individual territories in Denmark. Journal of ornithology, 153(3), 677-689.
  54. ^ Glue, D. (1973). Seasonal mortality in four small birds of prey. Ornis Scandinavica, 97-102.
  55. ^ McGhie, H. (1999). Persecution of birds of prey in north Scotland 1912-69 as evidenced by taxidermists' stuffing books. Scottish birds, 20(2), 98-110.
  56. ^ Glue, D. E. (1971). Ringing recovery circumstances of small birds of prey. Bird Study, 18(3), 137-146.
  57. ^ Marzluff, J. M. (2001). Worldwide urbanization and its effects on birds. In Avian ecology and conservation in an urbanizing world (pp. 19-47). Springer, Boston, MA.
  58. ^ Leighton, K., Chilvers, D., Charles, A., & Kelly, A. (2008). Post-release survival of hand-reared tawny owls (Strix aluco) based on radio-tracking and leg-band return data. Animal welfare, 17(3), 207-214.
  59. ^ Griffiths, R., Murn, C., & Clubb, R. (2010). Survivorship of rehabilitated juvenile Tawny Owls (Strix aluco) released without support food, a radio tracking study. Avian Biology Research, 3(1), 1-6.
  60. ^ Illner, H. (1992). Road deaths of Westphalian owls: methodological problems, influence of road type and possible effects of population levels. Pages 94-100 in C.A. Galbraith, I. Taylor, and S. Percival [EDS.], The ecology and conservation of European owls. Joint Nature Conservation Committee, Peterborough, U.K.
  61. ^ Williams, D. L., Villavincencio, C. G., & Wilson, S. (2006). Chronic ocular lesions in tawny owls (Strix aluco) injured by road traffic. Veterinary Record, 159(5), 148-153.
  62. ^ Cousquer, G. (2005). Ophthalmological findings in free-living tawny owls (Strix aluco) examined at a wildlife veterinary hospital. Veterinary record, 156(23), 734-739.
  63. ^ Baudvin, H., & Jouaire, S. (2003). Les causes de mortalité chez les chouettes hulottes adultes Strix aluco dans quelques forêts de Bourgogne. Alauda, 71(2), 221-226.
  64. ^ Santos, S. M., Lourenço, R., Mira, A., & Beja, P. (2013). Relative effects of road risk, habitat suitability, and connectivity on wildlife roadkills: the case of tawny owls (Strix aluco). PLoS One, 8(11), e79967.
  65. ^ Silva, C. C., Lourenço, R., Godinho, S., Gomes, E., Sabino-Marques, H., Medinas, D., Neves, M., Silva, C., Rabaca, J.E. & Mira, A. (2012). Major roads have a negative impact on the Tawny Owl Strix aluco and the Little Owl Athene noctua populations. Acta ornithologica, 47(1), 47-54.
  66. ^ Fröhlich, A., & Ciach, M. (2018). Noise pollution and decreased size of wooded areas reduces the probability of occurrence of Tawny Owl Strix aluco. Ibis, 160(3), 634-646.
  67. ^ Conrad, B. (1977) Die Giftbelastung der Vogelwelt Deutschlands. Vogelkundliche Bibliothek Vol. 5, Kilda-Verlag, Greven.
  68. ^ Debén, S., Fernández, J. Á., Aboal, J. R., & Carballeira, A. (2012). Evaluation of different contour feather types for biomonitoring lead exposure in Northern goshawk (Accipiter gentilis) and tawny owl (Strix aluco). Ecotoxicology and environmental safety, 85, 115-119.
  69. ^ Varela, Z., García-Seoane, R., Fernández, J. A., Carballeira, A., & Aboal, J. R. (2016). Study of temporal trends in mercury concentrations in the primary flight feathers of Strix aluco. Ecotoxicology and environmental safety, 130, 199-206.
  70. ^ Seoane, R. G., Río, Z. V., Ocaña, A. C., Escribano, J. Á. F., & Viñas, J. R. A. (2018). Selection of tawny owl (Strix aluco) flight feather shaft for biomonitoring As, Cd and Pb pollution. Environmental Science and Pollution Research, 25(14), 14271-14276.
  71. ^ Ahrens, L., Herzke, D., Huber, S., Bustnes, J. O., Bangjord, G., & Ebinghaus, R. (2011). Temporal trends and pattern of polyfluoroalkyl compounds in tawny owl (Strix aluco) eggs from Norway, 1986− 2009. Environmental science & technology, 45(19), 8090-8097.
  72. ^ Walker, L. A., Turk, A., Long, S. M., Wienburg, C. L., Best, J., & Shore, R. F. (2008). Second generation anticoagulant rodenticides in tawny owls (Strix aluco) from Great Britain. Science of the Total Environment, 392(1), 93-98.
  73. ^ Eriksson, U., Roos, A., Lind, Y., Hope, K., Ekblad, A., & Kärrman, A. (2016). Comparison of PFASs contamination in the freshwater and terrestrial environments by analysis of eggs from osprey (Pandion haliaetus), tawny owl (Strix aluco), and common kestrel (Falco tinnunculus). Environmental research, 149, 40-47.
  74. ^ Hahn, E., Hahn, K., & Stoeppler, M. (1993). Bird feathers as bioindicators in areas of the German environmental specimen bank-bioaccumulation of mercury in food chains and exogenous deposition of atmospheric pollution with lead and cadmium. Science of the Total Environment, 139, 259-270.
  75. ^ Armstrong, Edward A. (1958). The Folklore of Birds: An Enquiry into the Origin and Distribution of Some Magico-Religious Traditions. London: Collins. p. 114.
  76. ^ Wordsworth, William; Coleridge, Samuel Taylor (1800). Lyrical Ballads. London: Longman.

External links[edit]

Listen to this article (24 minutes)
Spoken Wikipedia icon
This audio file was created from a revision of this article dated 8 April 2009 (2009-04-08), and does not reflect subsequent edits.
(Audio help · More spoken articles)
Retrieved from "https://en.wikipedia.org/w/index.php?title=Tawny_owl&oldid=1056501350"