---
title: "What the sources say about the Tawny Owl | AnimalTracks.wiki"
description: "47 claims from the Tawny Owl profile, each beside the words of the source that backs it."
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canonical: "https://animaltracks.wiki/animals/tawny-owl/sources/"
---

# What the sources say about the Tawny Owl (*Strix aluco*)

> 47 claims from the Tawny Owl profile, each beside the words of the source that backs it. A "..." marks a cut in a quote and [brackets] an insertion.

Profile: [Tawny Owl](https://animaltracks.wiki/animals/tawny-owl/)

## Strix aluco (tawny owl). Animal Diversity Web, University of Michigan.

https://animaldiversity.org/accounts/Strix_aluco/

| The page says | The source says |
| :--- | :--- |
| lopsided ears | Their two ear openings have different structures and are located asymmetrically on the head for directional hearing (note: 'lopsided' for 'located asymmetrically') |
| Mature broadleaf woodland with old, hole-bearing trees, parks and large gardens, and some conifer forest | Tawny owls live in open, deciduous, or mixed forest or woodland, agricultural areas with trees, parks, cemeteries, and large gardens ... While sometimes found in mature conifer forests as well, they prefer mature broadleaf trees, such as ancient oaks with large holes for nesting. |
| across the Palearctic from Iberia to China and Korea | Strix aluco can be found across the Palearctic Region from the Iberian Peninsula to as far east as China and Korea |
| Mostly woodland rodents, plus other small mammals, amphibians, beetles, worms, and birds | Tawny owls prey on a variety of animals, ranging from mostly woodland rodents to other small mammals, amphibians, birds, beetles, and worms. |
| Asymmetrical ear openings that let it locate a sound from the tiny difference in when it reaches each ear | Their two ear openings have different structures and are located asymmetrically on the head for directional hearing ... These owls can use the minute differences in the time of arrival of sound at each ear to locate the source. |
| A Hunter That Finds Prey By Ear | These owls can use the minute differences in the time of arrival of sound at each ear to locate the source. (note: heading; the owl uses sound to locate its source) |
| A tawny owl hunts mostly between dusk and dawn, and for a night hunter, hearing is crucial | Hearing is a crucial sense for a nocturnal hunter. ... Tawny owls hunt primarily between dusk and dawn. |
| Its eyes sit at the front of its head with a 50 to 70 percent overlap between their fields, which gives it more binocular vision than birds that hunt by day | Tawny owl eyes are at the front of the head, with a field overlap of 50 to 70%. This overlap enables greater binocular vision than birds that hunt during the day. |
| Its two ear openings are built differently and set asymmetrically on the head, and the left one tilts downward to catch sounds from below | Their two ear openings have different structures and are located asymmetrically on the head for directional hearing ... The left ear tilts downward to catch sounds coming from below. |
| The owl locates a sound from the tiny difference in when it reaches each ear | These owls can use the minute differences in the time of arrival of sound at each ear to locate the source. |
| It perches and watches, then glides down silently to catch its prey on the ground, covering it with its wings and killing it with its feet and claws | They perch and watch for prey, then use silent gliding flight to catch their victim on the ground, extending the wings to cover the prey and killing it with feet and claws. |
| Rain is its weak spot: the noise of rainfall easily interferes with its hearing, and prolonged rain can leave it unable to hunt and starving | this acute hearing can be easily interfered with by the sound of rainfall. Prolonged rain can bring about an inability to hunt and inevitable starvation. |
| It averages 38 centimeters long with a 99-centimeter wingspan | Average length 38 cm ... Average wingspan 99 cm |
| Its range runs across the Palearctic, from the Iberian Peninsula east to China and Korea and south to Iran and the Himalayas | Strix aluco can be found across the Palearctic Region from the Iberian Peninsula to as far east as China and Korea and south to Iran and the Himalayan mountain range. |
| Its diet is mostly woodland rodents, with other small mammals, amphibians, beetles and worms, and birds make up a bigger share of it in towns and cities | Tawny owls prey on a variety of animals, ranging from mostly woodland rodents to other small mammals, amphibians, birds, beetles, and worms. Birds represent a larger percentage of their diet in urban areas |
| A pair defends its territory year-round, with minor changes to the boundaries each year | The pair defend their territory year-round with minor changes to boundaries each year. |
| stakes it out with screeching calls, threats or fights in mid-flight | These owls are highly territorial and establish their territories with screeching calls, threatening behavior, or in fights mid-flight. |
| Territories run from about 0.12 to 1 square kilometer, smaller in dense woodland and larger where prey is scarce | Range territory size 0.12 to 1 km^2 ... Territory size of tawny owls depends on the habitat and availability of preferred prey. Territories can range from 30 acres in heavy woodland to 175 acres average in a beechwood forest with less vegetation. In Norway, where prey density is low, territories range about 255 acres. (note: 30-255 acres is roughly 0.12-1.03 km², matching ADW's own range figure) |
| Talons Aimed at the Eyes | Tawny owls defend their nest and young fiercely, even in the daytime, striking with sharp talons at the intruder's head and eyes. (note: blockquote lead) |
| A tawny owl defending its nest and young strikes with its talons at an intruder's head and eyes, and mothers guarding a brood attack even people and domestic animals | Tawny owls defend their nest and young fiercely, even in the daytime, striking with sharp talons at the intruder's head and eyes. ... Tawny owl mothers aggressively defending their broods, even against humans and domestic animals |
| Tawny owl plumage varies from rufous-brown to greyish-brown, with lighter grey-and-white birds in the northernmost parts of the range | These owls exhibit geographic variation in color. They can be rufous-brown; greyish-brown with the mottled plumage ... or lighter grey and white (in the northernmost parts of their distribution). |
| A sound reaches one of its ears a tiny fraction of a second before the other, and the owl uses that difference to work out where it came from | These owls can use the minute differences in the time of arrival of sound at each ear to locate the source. (note: paraphrase: one ear hearing the sound 'before' the other is what 'minute differences in the time of arrival of sound at each ear' means) |
| Its ears sit under the feathers of its facial disc, which let sound straight through, supported by a movable flap of skin | The ears are underneath the facial disk feathers, which are transparent to sound and supported by the movable pre-aural flap. |
| Rain is the catch: the noise of rainfall easily interferes with its hearing | this acute hearing can be easily interfered with by the sound of rainfall. |
| Yes, if someone comes too close to its nest or young, which it defends fiercely even in daylight | Tawny owls defend their nest and young fiercely, even in the daytime |
| Its flight is silent, so the first warning can be the strike itself | Their silent flight give them the ability to attack without notice. (note: the cause is the source's own: silent flight 'give[s] them the ability to attack without notice') |
| Owls from Siberia and Scandinavia are bigger than western European birds: about 12 percent larger and 40 percent heavier, with wings roughly 13 percent longer | Siberian and Scandinavian subspecies are 12% larger and 40% heavier than western European tawny owls, with 13% longer wings. |
| dangerLevel: Medium | Tawny owls defend their nest and young fiercely, even in the daytime, striking with sharp talons at the intruder's head and eyes. (note: Settles #732: it attacks people at the nest and can injure them, so not Low (effectively harmless); no source describes a death, so not Deadly.) |
| tags: carnivore | Tawny owls prey on a variety of animals, ranging from mostly woodland rodents to other small mammals, amphibians, birds, beetles, and worms. (note: Settles #732: replaces insectivore, since insects are a minor share of a mostly rodent diet.) |

## Tawny Owl. BTO BirdFacts, British Trust for Ornithology.

https://www.bto.org/understanding-birds/birdfacts/tawny-owl

| The page says | The source says |
| :--- | :--- |
| a 'too-whit-too-woo' that takes two birds to make | the familiar 'too-whit-too-woo' call which is actually made by two birds |
| Live adults weighed by British ringers average about 396 grams for males and 502 grams for females | Wing length and body weights are from live birds ... Female 502.2±58.6 g (400-600 g, N=179) Male 396±44.6 g (335-482 g, N=37) (note: 502 rounds BTO's 502.2 g female average; BTO's current ringing biometrics replace ADW's older 420/520 g averages) |
| British ringing records put a tawny owl's typical life expectancy at 4 years once it reaches breeding age, and the oldest ringed bird lived 23 years, 5 months and 27 days, a record set in 2016 | Typical life expectancy of bird reaching breeding age 4 years ... Maximum age from a ringed bird 23 years, 5 months, 27 days (set in 2016) |
| It lives in woodland throughout Britain, though not on the Northern Isles, the Outer Hebrides or treeless uplands, and it is absent from Ireland | Tawny Owls are resident in woodlands throughout Britain but absent from the Channel Islands and Ireland ... Within Britain they are absent from the Northern Isles, Outer Hebrides, some of the smaller Inner Hebridean islands, the Isles of Scilly and treeless upland areas elsewhere (note: 'some' qualifies the smaller Inner Hebridean islands, which the sentence leaves out; the islands and uplands it names are stated flatly) |
| Two Birds, One Hoot | which is actually made by two birds (note: heading) |
| The familiar "too-whit-too-woo" is made by two birds: the female calls the "too-whit" in answer to the male's hooting "too-woo." | It is the source of the familiar 'too-whit-too-woo' call which is actually made by two birds – the female is responsible for the 'too-whit' part when she answers to the male's hooting 'too-woo'. |
| the owl's 'too-whit-too-woo' takes two birds: one calls the 'too-whit' in answer to the other's hooting 'too-woo' | the familiar 'too-whit-too-woo' call which is actually made by two birds – the female is responsible for the 'too-whit' part when she answers to the male's hooting 'too-woo'. (note: vibe.reason, settled in #732 (was mood only).) |

## Tawny owl. RSPB, Royal Society for the Protection of Birds.

https://www.rspb.org.uk/birds-and-wildlife/tawny-owl

| The page says | The source says |
| :--- | :--- |
| Broad rounded wings | Broad rounded wings and a short tail |
| Built Like a Woodpigeon | The Tawny Owl is an owl the size of a Woodpigeon. (note: heading) |
| A tawny owl is about the size of a woodpigeon: a rounded body and head with no ear tufts, and a ring of dark feathers around its face surrounding its dark eyes | The Tawny Owl is an owl the size of a Woodpigeon. It has a rounded body and head, with a ring of dark feathers around its face surrounding the dark eyes. ... Rounded head with no ear tufts |

## Brommer, Ahola & Karstinen (2005). The colour of fitness: plumage coloration and lifetime reproductive success in the tawny owl. Proceedings of the Royal Society B: Biological Sciences.

https://doi.org/10.1098/rspb.2005.3052

| The page says | The source says |
| :--- | :--- |
| Grey or Brown: A Coat That Comes With Consequences | Grey-coloured male and female owls had a higher lifetime production of fledglings, and grey-coloured male (but not female) owls produced more recruits during their lifetime than brown individuals. (note: heading; the consequences are the fitness differences) |
| The colour is highly heritable, and a 26-year study of a population in southern Finland found it mattered for more than looks | a population of tawny owls (Strix aluco) in southern Finland, using 26 years of data ... Colour was a highly heritable trait and was under selection. |
| grey males and females produced more fledglings over their lifetimes than brown owls did, and grey males also produced more young that went on to join the breeding population | Grey-coloured male and female owls had a higher lifetime production of fledglings, and grey-coloured male (but not female) owls produced more recruits during their lifetime than brown individuals. (note: 'young that went on to join the breeding population' defines 'recruits') |
| The study found that selection worked through survival, not through fecundity | Selection on colour was mediated through viability selection and not through fecundity selection. (note: 'survival' for 'viability selection') |
| Plumage colour is highly heritable | Colour was a highly heritable trait |
| In a southern Finnish population followed for 26 years, owls scored from pale grey to reddish brown fell into two clusters, a grey morph and a brown morph, in both sexes | in southern Finland, using 26 years of data on individually marked male and female owls. Colour was scored on a semi-continuous scale from pale grey to reddish brown. Colour scoring was repeatable and showed a bimodal distribution (grey and brown morph) in both sexes. |
| The mix of colours stayed stable through the study, and the owls did not choose mates by colour | During the study period, colour composition was stable in the study population in both sexes. The sexes did not mate assortatively with respect to their colour. |

## Strix aluco. The IUCN Red List of Threatened Species 2024: e.T22725469A264546097.

https://doi.org/10.2305/iucn.uk.2024-2.rlts.t22725469a264546097.en

| The page says | The source says |
| :--- | :--- |
| Least Concern | Least Concern (note: IUCN category read through GBIF's copy of the Red List; iucnredlist.org refuses scripts) |