The western barn owl (''Tyto alba'') is usually considered a subspecies group and together with the
American barn owl
The American barn owl (''Tyto furcata'') is usually considered a subspecies group and together with the western barn owl group, the eastern barn owl group, and sometimes the Andaman masked owl, make up the barn owl, cosmopolitan in range. The ba ...
group, the
eastern barn owl
The eastern barn owl (''Tyto javanica'') is usually considered a subspecies group and together with the American barn owl group, the western barn owl group, and sometimes the Andaman masked owl make up the barn owl. The cosmopolitan barn owl is ...
group, and sometimes the
Andaman masked owl
The Andaman masked owl (''Tyto deroepstorffi'') is a barn owl endemic to the southern Andaman Islands, an archipelago between India and Myanmar, in the Bay of Bengal.Bruce, M.D., Christie, D.A., Kirwan, G.M. & Marks, J.S. (2017). Common Barn-ow ...
make up the
barn owl
The barn owl (''Tyto alba'') is the most widely distributed species of owl in the world and one of the most widespread of all species of birds, being found almost everywhere except for the polar and desert regions, Asia north of the Himalaya ...
. The cosmopolitan barn owl is recognized by most taxonomic authorities. A few (including the
International Ornithologists' Union
The International Ornithologists' Union, formerly known as the International Ornithological Committee, is a group of about 200 international ornithologists, and is responsible for the International Ornithological Congress and other international ...
) separate them
Taxonomy
The western barn owl was
formally described in 1769 by the Austrian naturalist
Giovanni Antonio Scopoli
Giovanni Antonio Scopoli (sometimes Latinisation of names, Latinized as Johannes Antonius Scopolius) (3 June 1723 – 8 May 1788) was an Italian physician and natural history, naturalist. His biographer Otto Guglia named him the "first anational ...
under the
binomial name
In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...
''Strix alba''. The
type locality is the
Friuli
Friuli ( fur, Friûl, sl, Furlanija, german: Friaul) is an area of Northeast Italy with its own particular cultural and historical identity containing 1,000,000 Friulians. It comprises the major part of the autonomous region Friuli Venezia Giulia ...
area of northeast Italy. The specific epithet is from
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
''albus'' meaning "white". This owl is now placed in the
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
''
Tyto
''Tyto'' is a genus of birds consisting of true barn owls, grass owls and masked owls that collectively make up all the species within the subfamily Tytoninae of the barn owl family, Tytonidae.
Taxonomy
The genus ''Tyto'' was introduced in 1828 ...
'' that was introduced in 1828 by the Swedish naturalist
Gustaf Johan Billberg
Gustaf Johan Billberg (14 June 1772, Karlskrona – 26 November 1844, Stockholm) was a Swedish botanist, zoologist and anatomist, although professionally and by training he was a lawyer and used science and biology as an avocation. The plant genu ...
.
Ten
subspecies
In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...
are recognised:
[
* ''T. a. alba'' (]Scopoli
Giovanni Antonio Scopoli (sometimes Latinized as Johannes Antonius Scopolius) (3 June 1723 – 8 May 1788) was an Italian physician and naturalist. His biographer Otto Guglia named him the "first anational European" and the "Linnaeus of the Au ...
, 1769) – northwest Africa, west, south Europe to the Balkans
* ''T. a. guttata'' ( Brehm, CL, 1831) – central Europe and east Balkans to the Ukraine
* ''T. a. ernesti'' ( Kleinschmidt, 1901 – Corsica and Sardinia
* ''T. a. erlangeri'' Sclater, WL, 1921 – Crete and Cyprus through the Middle East to south Iran
* ''T. a. schmitzi'' ( Hartert, E, 1900) – Madeira
)
, anthem = ( en, "Anthem of the Autonomous Region of Madeira")
, song_type = Regional anthem
, image_map=EU-Portugal_with_Madeira_circled.svg
, map_alt=Location of Madeira
, map_caption=Location of Madeira
, subdivision_type=Sovereign st ...
* ''T. a. gracilirostris'' (Hartert, E, 1905) – east Canary Islands
The Canary Islands (; es, Canarias, ), also known informally as the Canaries, are a Spanish autonomous community and archipelago in the Atlantic Ocean, in Macaronesia. At their closest point to the African mainland, they are west of Morocc ...
* ''T. a. detorta'' Hartert, E, 1913 – Cape Verde
, national_anthem = ()
, official_languages = Portuguese
, national_languages = Cape Verdean Creole
, capital = Praia
, coordinates =
, largest_city = capital
, demonym ...
Islands
* ''T. a. poensis'' (Fraser Fraser may refer to:
Places Antarctica
* Fraser Point, South Orkney Islands
Australia
* Fraser, Australian Capital Territory, a suburb in the Canberra district of Belconnen
* Division of Fraser (Australian Capital Territory), a former federal ele ...
, 1843) – Africa south of the Sahara, island of Bioko
Bioko (; historically Fernando Po; bvb, Ëtulá Ëria) is an island off the west coast of Africa and the northernmost part of Equatorial Guinea. Its population was 335,048 at the 2015 census and it covers an area of . The island is located of ...
(Gulf of Guinea) (includes ''affinis'')
* ''T. a. thomensis'' ( Hartlaub, 1852) – island of São Tomé
São Tomé is the capital and largest city of the Central African island country of São Tomé and Príncipe. Its name is Portuguese for " Saint Thomas". Founded in the 15th century, it is one of Africa's oldest colonial cities.
History
Álva ...
(Gulf of Guinea)
* ''T. a. hypermetra'' Grote, 1928 – Comoros
The Comoros,, ' officially the Union of the Comoros,; ar, الاتحاد القمري ' is an independent country made up of three islands in southeastern Africa, located at the northern end of the Mozambique Channel in the Indian Ocean. It ...
and Madagascar
Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...
Distribution
Its range includes all of Europe (except Fennoscandia and Malta), and most of Africa apart from the Sahara.
In continental Europe the distance travelled is greater, commonly somewhere between but exceptionally , with ringed birds from the Netherlands ending up in Spain and in Ukraine. Movements in the African continent include from Senegambia to Sierra Leone and up to within South Africa.
Behaviour and ecology
Like most owls, the barn owl is nocturnal
Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite.
Nocturnal creatures generally have highly developed sens ...
, relying on its acute sense of hearing when hunting in complete darkness. It often becomes active shortly before dusk and can sometimes be seen during the day when relocating from one roosting site to another. In Britain, it sometimes hunts by day. This practice may depend on whether the owl is mobbed
''Mobbed'' is an American hidden camera reality television show based on the use of flash mobs as part of the spectacle for the delivery of an important personal message. The show, created by Howie Mandel, Darryl Trell, and Howard Kitrosser, aire ...
by other birds if it emerges in daylight. However, in Britain, some birds continue to hunt by day even when mobbed by such birds as magpies
Magpies are birds of the Corvidae family. Like other members of their family, they are widely considered to be intelligent creatures. The Eurasian magpie, for instance, is thought to rank among the world's most intelligent creatures, and is one ...
, rooks
Rook (''Corvus frugilegus'') is a bird of the corvid family. Rook or rooks may also refer to:
Games
*Rook (chess), a piece in chess
*Rook (card game), a trick-taking card game
Military
*Sukhoi Su-25 or Rook, a close air support aircraft
* USS ...
and black-headed gull
The black-headed gull (''Chroicocephalus ridibundus'') is a small gull that breeds in much of the Palearctic including Europe and also in coastal eastern Canada. Most of the population is migratory and winters further south, but some birds res ...
s, such diurnal activity possibly occurring when the previous night has been wet making hunting difficult. By contrast, in southern Europe and the tropics, the birds seem to be almost exclusively nocturnal, with the few birds that hunt by day being severely mobbed.
Barn owls are not particularly territorial
A territory is an area of land, sea, or space, particularly belonging or connected to a country, person, or animal.
In international politics, a territory is usually either the total area from which a state may extract power resources or a ...
but have a home range inside which they forage. For males in Scotland this has a radius of about from the nest site and an average size of about 300 hectares. Female home ranges largely coincide with that of their mates. Outside the breeding season, males and females usually roost separately, each one having about three favoured sites in which to conceal themselves by day, and which are also visited for short periods during the night. Roosting sites include holes in trees, fissures in cliffs, disused buildings, chimneys and haysheds and are often small in comparison to nesting sites. As the breeding season approaches, the birds move back to the vicinity of the chosen nest to roost.[Taylor (2004) pp. 96–107]
The barn owl is a bird of open country such as farmland
Agricultural land is typically land ''devoted to'' agriculture, the systematic and controlled use of other forms of lifeparticularly the rearing of livestock and production of cropsto produce food for humans. It is generally synonymous with bot ...
or grassland
A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur natur ...
with some interspersed woodland, usually at altitudes below but occasionally as high as in the tropics
The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in
the Southern Hemisphere at S. The tropics are also referred to ...
. This owl prefers to hunt along the edges of woods or in rough grass strips adjoining pasture. It has an effortless wavering flight as it quarters the ground, alert to the sounds made by potential prey. Like most owls, the barn owl flies silently; tiny serrations on the leading edges of its flight feather
Flight feathers (''Pennae volatus'') are the long, stiff, asymmetrically shaped, but symmetrically paired pennaceous feathers on the wings or tail of a bird; those on the wings are called remiges (), singular remex (), while those on the tail ...
s and a hairlike fringe to the trailing edges help to break up the flow of air over the wings, thereby reducing turbulence
In fluid dynamics, turbulence or turbulent flow is fluid motion characterized by chaotic changes in pressure and flow velocity. It is in contrast to a laminar flow, which occurs when a fluid flows in parallel layers, with no disruption between ...
and the noise that accompanies it. Hairlike extensions to the barbule
Feathers are epidermal growths that form a distinctive outer covering, or plumage, on both avian (bird) and some non-avian dinosaurs and other archosaurs. They are the most complex integumentary structures found in vertebrates and a premier ...
s of its feathers, which give the plumage a soft feel, also minimise noise produced during wingbeats.[Taylor (2004) pp. 47–61] The behaviour and ecological preferences may differ slightly even among neighbouring subspecies, as shown in the case of the European ''T. a. guttata'' and ''T. a. alba'' that probably evolved, respectively, in allopatric
Allopatric speciation () – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model – is a mode of speciation that occurs when biological populations become geographically isolated from ...
glacial refugia A glacial refugium (''plural refugia'') is a geographic region which made possible the survival of flora and fauna in times of ice ages and allowed for post-glacial re-colonization. Different types of glacial refugia can be distinguished, namely nu ...
in southeastern Europe, and in Iberia
The Iberian Peninsula (),
**
* Aragonese and Occitan: ''Peninsula Iberica''
**
**
* french: Péninsule Ibérique
* mwl, Península Eibérica
* eu, Iberiar penintsula also known as Iberia, is a peninsula in southwestern Europe, defi ...
or southern France.[Ehrlich et al. (1994) pp. 250–254]
Diet and feeding
The diet of the barn owl has been much studied; the items consumed can be ascertained from identifying the prey fragments in the pellets of indigestible matter that the bird regurgitates. Studies of diet have been made in most parts of the bird's range, and in moist temperate areas over 90% of the prey tends to be small mammals, whereas in hot, dry, unproductive areas, the proportion is lower, and a great variety of other creatures are eaten depending on local abundance. Most prey is terrestrial but bat
Bats are mammals of the order Chiroptera.''cheir'', "hand" and πτερόν''pteron'', "wing". With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more agile in flight than most bi ...
s and birds are also taken, as well as lizard
Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia alt ...
s, amphibian
Amphibians are tetrapod, four-limbed and ectothermic vertebrates of the Class (biology), class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terres ...
s and insect
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...
s. Even when they are plentiful and other prey scarce, earthworm
An earthworm is a terrestrial invertebrate that belongs to the phylum Annelida. They exhibit a tube-within-a-tube body plan; they are externally segmented with corresponding internal segmentation; and they usually have setae on all segments. Th ...
s do not seem to be consumed.[Taylor (2004) pp. 29–46]
In most of Europe, vole
Voles are small rodents that are relatives of lemmings and hamsters, but with a stouter body; a longer, hairy tail; a slightly rounder head; smaller eyes and ears; and differently formed molars (high-crowned with angular cusps instead of low-c ...
s predominate in the diet and shrew
Shrews (family Soricidae) are small mole-like mammals classified in the order Eulipotyphla. True shrews are not to be confused with treeshrews, otter shrews, elephant shrews, West Indies shrews, or marsupial shrews, which belong to different fa ...
s are the second most common food choice. Mice and rats form the main foodstuffs in the Mediterranean region. Barn owls are usually more specialist feeders in productive areas and generalists in drier areas.[ On the Cape Verde Islands, geckos are the mainstay of the diet, supplemented by birds such as ]plover
Plovers ( , ) are a widely distributed group of wading birds belonging to the subfamily Charadriinae.
Description
There are about 66 species in the subfamily, most of them called "plover" or "dotterel". The closely related lapwing subfa ...
s, godwit
The godwits are a group of large, long-billed, long-legged and strongly migratory waders of the bird genus ''Limosa''. Their long bills allow them to probe deeply in the sand for aquatic worms and molluscs. In their winter range, they floc ...
s, turnstone
Turnstones are two bird species that comprise the genus ''Arenaria'' in the family Scolopacidae. They are closely related to calidrid sandpipers and might be considered members of the tribe Calidriini.
The genus ''Arenaria'' was introduced by t ...
s, weavers
Weaver or Weavers may refer to:
Activities
* A person who engages in weaving fabric
Animals
* Various birds of the family Ploceidae
* Crevice weaver spider family
* Orb-weaver spider family
* Weever (or weever-fish)
Arts and entertainment
...
and pratincole
The pratincoles or greywaders are a group of birds which together with the coursers make up the family Glareolidae. They have short legs, very long pointed wings and long forked tails.
Description
Their most unusual feature for birds classed a ...
s, and on a rocky islet off the coast of California, a clutch of four young were being reared on a diet of Leach's storm petrel
Leach's storm petrel or Leach's petrel (''Hydrobates leucorhous'') is a small seabird of the tubenose order. It is named after the British zoologist William Elford Leach. The scientific name is derived from Ancient Greek. ''Hydrobates'' is from ...
(''Oceanodroma leucorhoa''). In Ireland, the accidental introduction of the bank vole
The bank vole (''Myodes glareolus'') is a small vole with red-brown fur and some grey patches, with a tail about half as long as its body. A rodent, it lives in woodland areas and is around in length. The bank vole is found in much of Europe an ...
in the 1950s led to a major shift in the barn owl's diet: where their ranges overlap, the vole is now by far the largest prey item. Locally superabundant rodent species in the weight class of several grams per individual usually make up the single largest proportion of prey.[ The barn owl hunts by flying slowly, quartering the ground and hovering over spots that may conceal prey. It may also use branches, fence posts or other lookouts to scan its surroundings, and this is the main means of prey location.:) The bird has long, broad wings, enabling it to manoeuvre and turn abruptly. Its legs and toes are long and slender which improves its ability to forage among dense foliage or beneath the snow and gives it a wide spread of talons when attacking prey.][ Studies have shown that an individual barn owl may eat one or more voles (or their equivalent) per night, equivalent to about twenty-three percent of the bird's bodyweight. Excess food is often cached at roosting sites and can be used when food is scarce.][Taylor (2004) pp. 91–95]
Small prey is usually torn into chunks and eaten completely including bones and fur, while prey larger than about 100 g (4 oz), such as baby rabbit
Rabbits, also known as bunnies or bunny rabbits, are small mammals in the family Leporidae (which also contains the hares) of the order Lagomorpha (which also contains the pikas). ''Oryctolagus cuniculus'' includes the European rabbit speci ...
s, ''Cryptomys
''Cryptomys'' is the genus of mole-rats, endemic to Africa. Most of the species formerly placed in this genus were moved to the genus ''Fukomys
''Fukomys'' is a genus described in 2006 of common blesmol, mole-rats, containing several species ...
'' blesmol
The blesmols, also known as mole-rats, or African mole-rats, are burrowing rodents of the family Bathyergidae. They represent a distinct evolution of a subterranean life among rodents much like the pocket gophers of North America, the tuco-tuc ...
s, or ''Otomys
African vlei rats (''Otomys''), also known as groove-toothed rats, live in many areas of sub-Saharan Africa. Most species live in marshlands, grasslands, and similar habitats and feed on the vegetation of such areas, occasionally supplementing ...
'' vlei rats, is usually dismembered and the inedible parts discarded. Contrary to what is sometimes assumed, the barn owl does not eat domestic animals on any sort of regular basis. Regionally, non-rodent foods are used as per availability. On bird-rich islands, a barn owl might include some fifteen to twenty percent of birds in its diet, while in grassland it will gorge itself on swarming termite
Termites are small insects that live in colonies and have distinct castes (eusocial) and feed on wood or other dead plant matter. Termites comprise the infraorder Isoptera, or alternatively the epifamily Termitoidae, within the order Blattode ...
s, or on Orthoptera
Orthoptera () is an order of insects that comprises the grasshoppers, locusts, and crickets, including closely related insects, such as the bush crickets or katydids and wētā. The order is subdivided into two suborders: Caelifera – grassho ...
such as Copiphorinae katydid
Insects in the family Tettigoniidae are commonly called katydids (especially in North America), or bush crickets. They have previously been known as "long-horned grasshoppers". More than 8,000 species are known. Part of the suborder Ensifera, t ...
s, Jerusalem cricket
Jerusalem crickets (or potato bugs) are a group of large, flightless insects in the genera ''Ammopelmatus'' and ''Stenopelmatus'', together comprising the tribe Stenopelmatini. The former genus is native to the western United States and parts ...
s (Stenopelmatidae) or true cricket
Cricket is a bat-and-ball game played between two teams of eleven players on a field at the centre of which is a pitch with a wicket at each end, each comprising two bails balanced on three stumps. The batting side scores runs by striki ...
s (Gryllidae). Bats and even frog
A frog is any member of a diverse and largely Carnivore, carnivorous group of short-bodied, tailless amphibians composing the order (biology), order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-f ...
s, lizards and snakes may make a minor but significant contribution to the diet; small Soricomorpha
Soricomorpha (from Greek "shrew-form") is a formerly used taxon within the class of mammals. In the past it formed a significant group within the former order Insectivora. However, Insectivora was shown to be polyphyletic and various new orders w ...
like ''Suncus
''Suncus'' is a genus of shrews in the family Soricidae.
Classification
*Genus ''Suncus''
** Taita shrew, ''Suncus aequatorius''
** Black shrew, ''Suncus ater''
** Day's shrew, ''Suncus dayi''
** Etruscan shrew, ''Suncus etruscus''
** Sri Lan ...
'' shrews may be a secondary prey of major importance.
The barn owl has acute hearing, with ears placed asymmetrically. This improves detection of sound position and distance and the bird does not require sight to hunt. The facial disc plays a part in this process, as is shown by the fact that with the ruff feathers removed, the bird can still locate the source in azimuth
An azimuth (; from ar, اَلسُّمُوت, as-sumūt, the directions) is an angular measurement in a spherical coordinate system. More specifically, it is the horizontal angle from a cardinal direction, most commonly north.
Mathematicall ...
but fails to do so in elevation
The elevation of a geographic location is its height above or below a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface (see Geodetic datum § Vert ...
. Hunting nocturnally or crepuscular
In zoology, a crepuscular animal is one that is active primarily during the twilight period, being matutinal, vespertine, or both. This is distinguished from diurnal and nocturnal behavior, where an animal is active during the hours of daylig ...
ly, this bird can target its prey and dive to the ground, penetrating its talons through snow, grass or brush to seize small creatures with deadly accuracy. Compared to other owls of similar size, the barn owl has a much higher metabolic rate
Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...
, requiring relatively more food. Weight for weight, barn owls consume more rodents—often regarded as pests by humans—than possibly any other creature. This makes the barn owl one of the most economically valuable wildlife animals for agriculture. Farmers often find these owls more effective than poison in keeping down rodent pests, and they can encourage barn owl habitation by providing nest sites.
Breeding
Barn owls living in tropical regions can breed at any time of year, but some seasonality in nesting is still evident. Where there are distinct wet and dry seasons, egg-laying usually takes place during the dry season, with increased rodent prey becoming available to the birds as the vegetation dies off. In arid regions, breeding may be irregular and may happen in wet periods, triggered by temporary increases in the populations of small mammals. In temperate climate
In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout t ...
s, nesting seasons become more distinct and there are some seasons of the year when no egg-laying takes place. In Europe, most nesting takes place between March and June when temperatures are increasing. The actual dates of egg-laying vary by year and by location, being correlated with the amount of prey-rich foraging habitat around the nest site and often with the phase of the rodent abundance cycle.[Taylor (2004) pp. 121–135] An increase in rodent populations will usually stimulate the local barn owls to begin nesting; thus, even in the cooler parts of its range, two broods are often raised in a good year.
Females are ready to breed at 10 to 11 months of age, although males sometimes wait until the following year. Western barn owls are usually monogamous
Monogamy ( ) is a form of Dyad (sociology), dyadic Intimate relationship, relationship in which an individual has only one Significant other, partner during their lifetime. Alternately, only one partner at any one time (Monogamy#Serial monogamy, ...
, sticking to one partner for life unless one of the pair dies. During the non-breeding season they may roost separately, but as the breeding season approaches they return to their established nesting site, showing considerable site fidelity. In colder climates, in harsh weather and where winter food supplies may be scarce, they may roost in farm buildings and in barns between hay bales, but they then run the risk that their selected nesting hole may be taken over by some other, earlier-nesting species. Single males may establish feeding territories, patrolling the hunting areas, occasionally stopping to hover, and perching on lofty eminences where they screech to attract a mate. Where a female has lost her mate but maintained her breeding site, she usually seems to manage to attract a new spouse.[Shawyer (1994) pp. 67–87]
Once a pair-bond has been formed, the male will make short flights at dusk around the nesting and roosting sites and then longer circuits to establish a home range. When he is later joined by the female, there is much chasing, turning and twisting in flight, and frequent screeches, the male's being high-pitched and tremulous and the female's lower and harsher. At later stages of courtship, the male emerges at dusk, climbs high into the sky and then swoops back to the vicinity of the female at speed. He then sets off to forage. The female meanwhile sits in an eminent position and preens, returning to the nest a minute or two before the male arrives with food for her. Such feeding behaviour of the female by the male is common, helps build the pair-bond and increases the female's fitness before egg-laying commences.[
]
Western barn owls are cavity nesters. They choose holes in trees, fissures in cliff faces, the large nests of other birds such as the hamerkop
The hamerkop (''Scopus umbretta'') is a medium-sized wading bird. It is the only living species in the genus ''Scopus'' and the family Scopidae. The species and family was long thought to sit with the Ciconiiformes but is now placed with the Pe ...
(''Scopus umbretta'') and old buildings such as farm sheds and church towers. Buildings are preferred to trees in wetter climates in the British Isles and provide better protection for fledglings from inclement weather. No nesting material is used as such but, as the female sits incubating the eggs, she draws in the dry furry material of which her regurgitated pellets are composed, so that by the time the chicks are hatched, they are surrounded by a carpet of shredded pellets. Oftentimes other birds such as jackdaw
Jackdaws are two species of bird in the genus ''Coloeus'' closely related to, but generally smaller than, the crows and ravens (''Corvus''). ''Coloeus'' is sometimes treated as a subgenus of ''Corvus'', including by the IUCN.Madge & Burn (1994) ...
s (''Corvus monedula'') nest in the same hollow tree or building and seem to live harmoniously with the owls.[Taylor (2004) pp. 136–148]
Before commencing laying, the female spends much time near the nest and is entirely provisioned by the male. Meanwhile, the male roosts nearby and may cache
Cache, caching, or caché may refer to:
Places United States
* Cache, Idaho, an unincorporated community
* Cache, Illinois, an unincorporated community
* Cache, Oklahoma, a city in Comanche County
* Cache, Utah, Cache County, Utah
* Cache County ...
any prey that is surplus to their requirements. When the female has reached peak weight, the male provides a ritual presentation of food and copulation occurs at the nest. The female lays eggs on alternate days and the clutch size averages about five eggs (range two to nine). The eggs are chalky white, somewhat elliptical and about the size of bantam's eggs, and incubation begins as soon as the first egg is laid. While she is sitting on the nest, the male is constantly bringing more provisions and they may pile up beside the female. The incubation period is about thirty days, hatching takes place over a prolonged period and the youngest chick may be several weeks younger than its oldest sibling. In years with plentiful supplies of food, there may be a hatching success rate of about 75%. The male continues to copulate with the female when he brings food which makes the newly hatched chicks vulnerable to injury.[
]
The chicks are at first covered with greyish-white down and develop rapidly. Within a week they can hold their heads up and shuffle around in the nest. The female tears up the food brought by the male and distributes it to the chicks. Initially these make a "chittering" sound but this soon changes into a food-demanding "snore". By two weeks old they are already half their adult weight and look naked as the amount of down is insufficient to cover their growing bodies. By three weeks old, quills are starting to push through the skin and the chicks stand, making snoring noises with wings raised and tail stumps waggling, begging for food items which are now given whole. The male is the main provider of food until all the chicks are at least four weeks old at which time the female begins to leave the nest and starts to roost elsewhere. By the sixth week the chicks are as big as the adults but have slimmed down somewhat by the ninth week when they are fully fledge
Fledging is the stage in a flying animal's life between hatching or birth and becoming capable of flight.
This term is most frequently applied to birds, but is also used for bats. For altricial birds, those that spend more time in vulnerable c ...
d and start leaving the nest briefly themselves. They are still dependent on the parent birds until about thirteen weeks and receive training from the female in finding, and eventually catching, prey.[
In temperate areas, the male owl moults rather later in the year than the female, at a time when there is an abundance of food, the female has recommenced hunting and the demands of the chicks are lessening. Unmated males without family responsibilities often start losing feathers earlier in the year. The moult follows a similar prolonged pattern to that of the female and the first sign that the male is moulting is often when a tail feather has been dropped at the roost. A consequence of moulting is the loss of thermal insulation.
]
Predators and parasites
The Eurasian eagle-owl
The Eurasian eagle-owl (''Bubo bubo'') is a species of eagle-owl that resides in much of Palearctic, Eurasia. It is also called the Uhu and it is occasionally abbreviated to just the eagle-owl in Europe. It is one of the largest species of owl, ...
(''B. bubo'') are noted predators of barn owls. In Africa, the principle predators of barn owls are Verreaux's eagle-owl
Verreaux's eagle-owl (''Bubo lacteus''), also commonly known as the milky eagle owl or giant eagle owl, is a member of the family Strigidae. This species is widespread in sub-Saharan Africa. A member of the genus ''Bubo'', it is the largest Afri ...
s and Cape eagle-owl
The Cape eagle-owl (''Bubo capensis'') is a species of owl in the family Strigidae. It is one of several large species of the eagle-owl genus ''Bubo''.
Range
Its range is limited to the southernmost regions of southern Africa as well as parts ...
s.[Steyn, P. (1983). ''Birds of prey of southern Africa: Their identification and life histories''. Croom Helm, Beckenham (UK). 1983.] In Europe, although less dangerous than the eagle owl, the chief diurnal predators are the northern goshawk
The northern goshawk (; ''Accipiter gentilis'') is a species of medium-large bird of prey, raptor in the Family (biology), family Accipitridae, a family which also includes other extant diurnal raptors, such as eagles, buzzards and harrier (bird) ...
(''Accipiter gentilis'') and the common buzzard
The common buzzard (''Buteo buteo'') is a medium-to-large bird of prey which has a large range. A member of the genus ''Buteo'', it is a member of the family Accipitridae. The species lives in most of Europe and extends its breeding range across ...
(''Buteo buteo''). About a dozen other large diurnal raptors and owls have also been reported as predators of barn owls, ranging from the scarcely larger tawny owl
The tawny owl (''Strix aluco''), also called the brown owl, is commonly found in woodlands across Europe to western Siberia, and has seven recognized subspecies. It is a stocky, medium-sized owl, whose underparts are pale with dark streaks, an ...
to the golden eagle
The golden eagle (''Aquila chrysaetos'') is a bird of prey living in the Northern Hemisphere. It is the most widely distributed species of eagle. Like all eagles, it belongs to the family Accipitridae. They are one of the best-known bird of p ...
.[Voous, K.H. 1988. ''Owls of the Northern Hemisphere''. The MIT Press, 0262220350.] The goshawk and the eagle owl are on the increase because of the greater protection these birds now receive.[
When disturbed at its roosting site, an angry barn owl lowers its head and sways it from side to side, or the head may be lowered and stretched forward and the wings drooped while the bird emits hisses and makes snapping noises with its beak. A defensive attitude involves lying flat on the ground or crouching with wings spread out.][Witherby (1943) pp. 343–347]
Lifespan
Unusually for such a medium-sized carnivorous
A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other sof ...
animal, the barn owl exhibits ''r''-selection, producing large number of offspring with a high growth rate, many of which have a relatively low probability of surviving to adulthood. While wild barn owls are thus decidedly short-lived, the actual longevity
The word " longevity" is sometimes used as a synonym for "life expectancy" in demography. However, the term ''longevity'' is sometimes meant to refer only to especially long-lived members of a population, whereas ''life expectancy'' is always d ...
of the species is much higher – captive individuals may reach twenty years of age or more. But occasionally, a wild bird reaches an advanced age. A Dutch owl was noted to have reached an age of seventeen years, ten months. Another captive barn owl, in England, lived to be over twenty-five years old. Taking into account such extremely long-lived individuals, the average lifespan of the barn owl is about four years, and statistically two-thirds to three-quarters of all adults survive from one year to the next. However, the mortality
Mortality is the state of being mortal, or susceptible to death; the opposite of immortality.
Mortality may also refer to:
* Fish mortality, a parameter used in fisheries population dynamics to account for the loss of fish in a fish stock throug ...
is not evenly distributed throughout the bird's life, and only one young in three manages to live to its first breeding attempt.[
The most significant cause of death in temperate areas is likely to be starvation, particularly over the autumn and winter period when first year birds are still perfecting their hunting skills. In northern and upland areas, there is some correlation between mortality in older birds and adverse weather, deep-lying snow and prolonged low temperatures. Collision with road vehicles is another cause of mortality, and may result when birds forage on mown verges. Some of these birds are in poor condition and may have been less able to evade oncoming vehicles than fit individuals would have been. Historically, many deaths were caused by the use of ]pesticide
Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and lampri ...
s, and this may still be the case in some parts of the world. Collisions with power-lines kill some birds and shooting accounts for others, especially in Mediterranean regions.[Taylor (2004) pp. 203–215]
Subspecies
Status and conservation
Barn owls are relatively common throughout most of their range and not considered globally threatened. However, locally severe declines from organochlorine
An organochloride, organochlorine compound, chlorocarbon, or chlorinated hydrocarbon is an organic compound containing at least one covalent bond, covalently bonded atom of chlorine. The chloroalkane class (alkanes with one or more hydrogens subst ...
(e.g., DDT
Dichlorodiphenyltrichloroethane, commonly known as DDT, is a colorless, tasteless, and almost odorless crystalline chemical compound, an organochloride. Originally developed as an insecticide, it became infamous for its environmental impacts. ...
) poisoning in the mid-20th century and rodenticide
Rodenticides are chemicals made and sold for the purpose of killing rodents. While commonly referred to as "rat poison", rodenticides are also used to kill mice, squirrels, woodchucks, chipmunks, porcupines, nutria, beavers, and voles. Despi ...
s in the late 20th century have affected some populations. Intensification of agricultural practices often means that the rough grassland that provides the best foraging habitat is lost.[Taylor (2004) pp. 242–261] While barn owls are prolific breeders and able to recover from short-term population decreases, they are not as common in some areas as they used to be. A 1995–1997 survey put their British population at between 3,000 and 5,000 breeding pairs, out of an average of about 150,000 pairs in the whole of Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...
. In the European Community
The European Economic Community (EEC) was a regional organization created by the Treaty of Rome of 1957,Today the largely rewritten treaty continues in force as the ''Treaty on the functioning of the European Union'', as renamed by the Lisbo ...
they are considered a Species of European Concern.[
]
In some areas, it may be an insufficiency of suitable nesting sites that is the factor limiting barn owl numbers. The provision of nest boxes under the eaves of buildings and in other locations can be very successful in increasing the local population.
The Canary barn owl is particularly at risk, and as late as 1975, hunting by fearful locals was limiting the population on Fuerteventura
Fuerteventura () is one of the Canary Islands, in the Atlantic Ocean, part of the North Africa region, and politically part of Spain. It is located away from the northwestern coast of Africa. The island was declared a biosphere reserve by UNES ...
where only a few dozen pairs remain. On Lanzarote
Lanzarote (, , ) is a Spanish island, the easternmost of the Canary Islands in the Atlantic Ocean. It is located approximately off the north coast of Africa and from the Iberian Peninsula. Covering , Lanzarote is the fourth-largest of the i ...
a somewhat larger number of these birds still seem to exist, but altogether this particular subspecies is precariously rare: Probably less than three hundred and perhaps fewer than two hundred individuals still remain. Similarly, the birds on the western Canary Islands
The Canary Islands (; es, Canarias, ), also known informally as the Canaries, are a Spanish autonomous community and archipelago in the Atlantic Ocean, in Macaronesia. At their closest point to the African mainland, they are west of Morocc ...
which are usually assigned to the nominate subspecies have declined much, and here wanton destruction seems still to be significant. On Tenerife they seem relatively numerous but on the other islands, the situation looks about as bleak as on Fuerteventura. Due to their assignment to the nominate subspecies, which is common in mainland Spain
, image_flag = Bandera de España.svg
, image_coat = Escudo de España (mazonado).svg
, national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond")
, national_anthem = (English: "Royal March")
, i ...
, the western Canary Islands population is not classified as threatened.
In the United Kingdom, the "Barn Owl Nest Box Scheme" is promoted by the World Owl Trust and has many participants in local areas such as Somerset
( en, All The People of Somerset)
, locator_map =
, coordinates =
, region = South West England
, established_date = Ancient
, established_by =
, preceded_by =
, origin =
, lord_lieutenant_office =Lord Lieutenant of Somerset
, lord_ ...
, where a webcam
A webcam is a video camera which is designed to record or stream to a computer or computer network. They are primarily used in videotelephony, livestreaming and social media, and security. Webcams can be built-in computer hardware or peripheral d ...
has been set up inside a nest box in which seven young were reared in 2014. In May 2012, it was revealed that farmers in Israel
Israel (; he, יִשְׂרָאֵל, ; ar, إِسْرَائِيل, ), officially the State of Israel ( he, מְדִינַת יִשְׂרָאֵל, label=none, translit=Medīnat Yīsrāʾēl; ), is a country in Western Asia. It is situated ...
and Jordan
Jordan ( ar, الأردن; tr. ' ), officially the Hashemite Kingdom of Jordan,; tr. ' is a country in Western Asia. It is situated at the crossroads of Asia, Africa, and Europe, within the Levant region, on the East Bank of the Jordan Rive ...
had, over a period of ten years, replaced pesticides with barn owls in a joint conservation venture called "Project Barn Owl".
References
Bibliography
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Further reading
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{{Authority control
Tyto, western barn owl
Falconry
Birds of Africa
Birds of Eurasia
Birds described in 1769, western barn owl
Taxa named by Giovanni Antonio Scopoli