Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Datasheet

Tyto alba
(Barn owl)

Toolbox

Datasheet

Tyto alba (Barn owl)

Summary

  • Last modified
  • 18 November 2019
  • Datasheet Type(s)
  • Invasive Species
  • Natural Enemy
  • Host Animal
  • Preferred Scientific Name
  • Tyto alba
  • Preferred Common Name
  • Barn owl
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Metazoa
  •     Phylum: Chordata
  •       Subphylum: Vertebrata
  •         Class: Aves
  • Summary of Invasiveness
  • T. alba was introduced to the Hawaiian Islands and Seychelles Islands to control invasive rat populations; it has also been introduced to St. Helena. It is known to prey on or compete with native birds in Hawai...

Don't need the entire report?

Generate a print friendly version containing only the sections you need.

Generate report

Pictures

Top of page
PictureTitleCaptionCopyright
Tyto alba (Barn owl); perched on a fence-post. Copp Rd, Kula, Maui, Hawaii, USA. June 21, 2007.
TitleAdult perched
CaptionTyto alba (Barn owl); perched on a fence-post. Copp Rd, Kula, Maui, Hawaii, USA. June 21, 2007.
Copyright©Forest Starr & Kim Starr - CC BY 4.0
Tyto alba (Barn owl); perched on a fence-post. Copp Rd, Kula, Maui, Hawaii, USA. June 21, 2007.
Adult perchedTyto alba (Barn owl); perched on a fence-post. Copp Rd, Kula, Maui, Hawaii, USA. June 21, 2007.©Forest Starr & Kim Starr - CC BY 4.0
Adult Barn Owl, (Tyto alba). Sonoran Desert Museum, Arizona, USA.
TitleAdult
CaptionAdult Barn Owl, (Tyto alba). Sonoran Desert Museum, Arizona, USA.
Copyright©Joy Viola/Northeastern University/Bugwood.org - CC BY-NC 3.0 US
Adult Barn Owl, (Tyto alba). Sonoran Desert Museum, Arizona, USA.
AdultAdult Barn Owl, (Tyto alba). Sonoran Desert Museum, Arizona, USA. ©Joy Viola/Northeastern University/Bugwood.org - CC BY-NC 3.0 US
Adult Barn Owl, (Tyto alba). Sonoran Desert Museum, Arizona, USA.
TitleAdult
CaptionAdult Barn Owl, (Tyto alba). Sonoran Desert Museum, Arizona, USA.
Copyright©Joy Viola/Northeastern University/Bugwood.org - CC BY-NC 3.0 US
Adult Barn Owl, (Tyto alba). Sonoran Desert Museum, Arizona, USA.
AdultAdult Barn Owl, (Tyto alba). Sonoran Desert Museum, Arizona, USA.©Joy Viola/Northeastern University/Bugwood.org - CC BY-NC 3.0 US

Identity

Top of page

Preferred Scientific Name

  • Tyto alba Scopoli 1769

Preferred Common Name

  • Barn owl

Other Scientific Names

  • Tyto perlata Ridgeway, 1914

International Common Names

  • English: Common Barn owl
  • Spanish: Lechuza Común
  • French: Effraie des clochers

Local Common Names

  • Germany: Schleiereule
  • UK: Demon Owl; Ghost Owl; Lesser Masked owl; Monkey-faced Owl; Night owl; White owl

Summary of Invasiveness

Top of page

T. alba was introduced to the Hawaiian Islands and Seychelles Islands to control invasive rat populations; it has also been introduced to St. Helena. It is known to prey on or compete with native birds in Hawaii and the Seychelles; in the Seychelles it nearly exterminated a local race of the White Tern (Gygis alba candida) before control measures were taken. As a native species, it is widely distributed around the world, and is itself a species of conservation concern in parts of its range, being listed as a Species of European Conservation Concern (Eaton et al., 2009) and as endangered in seven U.S. states, a species of concern in seven states, and threatened in three additional states (Marti et al., 2005).

Taxonomic Tree

Top of page
  • Domain: Eukaryota
  •     Kingdom: Metazoa
  •         Phylum: Chordata
  •             Subphylum: Vertebrata
  •                 Class: Aves
  •                     Order: Strigiformes
  •                         Family: Tytonidae
  •                             Genus: Tyto
  •                                 Species: Tyto alba

Notes on Taxonomy and Nomenclature

Top of page

There are between 28 and 35 recognized subspecies (the exact number is disputed), and 46 races, although differences between subspecies are understudied and several distinct species may lie within T. alba (Bruce 1999, Dickinson 2003). There are considerable distinctions between subspecies including feather coloration, wing, tail, and leg length; these are thought to be due to adaptation to the local environment.

Description

Top of page

T. alba is a medium-sized owl measuring 29-44 cm (variation within each subspecies is less than that across the species as a whole).  Body mass is highly variable between locations, with most ranging from 187-475 g (387- >600 g in Surinam and Malaysia and 400-700 g in North America) (Bruce, 1999).  The wing chord measures 80-95 cm (Mullarney et al., 1999).  Females are generally larger in all measurements except wing chord and tail length, and typically darker than males (Bruce, 1999; Marti et al., 2005).  Taylor (1993) recognized flecking under wings as a reliable marker for sexing T. alba alba: flecking indicated females and absence of flecks indicated males, but accuracy for other subspecies is unknown.

There is considerable plumage variation among subspecies and races (Bruce, 1999).  T. alba lacks the ear tufts common among owls and has a prominent heart-shaped face.  The iris is dark and the eyes small for Strigiformes (Bunn et al., 1982; Marti et al., 2005).  The wing feathers are rounded with 10 primaries, 15 secondaries, and 12 rectrices.  The legs are long and feathered, and the underparts buff with spotting on the wings and breast, although subspecies with primarily seabird diets may have lighter underparts and island subspecies may be darker (Bruce, 1999; Marti et al., 2005).

The young are altricial at hatching, and nidicolous.  They have bare skin on the neck, back, and belly, and thin whitish down on the tarsus, toes, and upperparts with an ivory bill.  Second natal down growth occurs at approximately 14 days (Marti et al., 2005).  The plumage of fledglings is similar to that of adults with more flecking, and may undergo a first prealternate molt prior to reaching adult basic plumage (Taylor, 1993).  Body mass exceeds that of adults during the growth stages and weight is lost prior to flight at 52-56 days, with full-fledging up to eight weeks after flight capability (Ehrlich et al., 1988; Marti et al., 2005).

Distribution

Top of page

T. alba is frequently cited as amongst the most cosmopolitan of owl species, with subspecies regionally distributed (Bruce, 1999; Marti, 2005; Konig and Weick, 2010). It is found on all continents except Antarctica. Its range is limited by severe cold due to an inability to store sufficient energy reserves (Marti, 2005). Vagrants are seen in northern regions of Canada, Europe and Russia, and one once reached the sub-Antarctic island of South Georgia (Bruce, 1999).

Distribution Table

Top of page

The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Last updated: 10 Jan 2020
Continent/Country/Region Distribution Last Reported Origin First Reported Invasive Reference Notes

Africa

AlgeriaPresentNativeBruce (1999)
AngolaPresentNativeBruce (1999)
BeninPresentNativeBirdLife International (2012)
BotswanaPresentNativeBruce (1999)
Burkina FasoPresentNativeBruce (1999)
BurundiPresentNativeBruce (1999)
Cabo VerdePresentNativeBirdLife International (2012)
CameroonPresentNativeBruce (1999)
Central African RepublicPresentNativeBruce (1999)
ChadPresentNativeBruce (1999)
ComorosPresentNativeKonig and Weick (2010)
Congo, Democratic Republic of thePresentNativeBruce (1999)
Congo, Republic of thePresentNativeBruce (1999)
Côte d'IvoirePresentNativeBruce (1999)
EgyptPresentNativeBruce (1999)
Equatorial GuineaPresentNativeBruce (1999)
EritreaPresent, Few occurrences2008NativeAsh and Atkins (2010)Two sightings reported since last publication of T. alba distribution in 1957
EswatiniPresentNativeBruce (1999)
EthiopiaPresent, Widespread2010NativeAsh and Atkins (2010)Primarily found throughout the Rift Valley
GabonPresentNativeBruce (1999)
GambiaPresentNativeBruce (1999)
GhanaPresentNativeBruce (1999)
GuineaPresentNativeBruce (1999)
Guinea-BissauPresentNativeBruce (1999)
KenyaPresentNativeBruce (1999)
LesothoPresentNativeBruce (1999)
LiberiaPresentNativeBruce (1999)
LibyaPresentNativeBruce (1999)
MadagascarPresentNativeBruce (1999)
MalawiPresentNativeBruce (1999)
MaliPresentNativeBruce (1999)
MauritaniaPresentNativeBruce (1999)
MayottePresentNativeBruce (1999)
MoroccoPresentNativeBruce (1999)
MozambiquePresentNativeBruce (1999)
NamibiaPresentNativeBruce (1999)
NigerPresentNativeBruce (1999)
NigeriaPresentNativeBruce (1999)
Saint HelenaPresentIntroducedLong (1981)Successfully introduced, population unknown
SeychellesPresent, LocalizedIntroduced1951InvasiveLong (1981); Lever (2010)Present on a number of granite islands
Sierra LeonePresentNativeBruce (1999)
SomaliaPresentNativeBruce (1999)
South AfricaPresentNativeBruce (1999)
SudanPresentNativeBruce (1999)
TanzaniaPresentNativeBruce (1999)
-Zanzibar IslandPresentNativeBruce (1999)
TogoPresentNativeBruce (1999)
TunisiaPresentNativeBruce (1999)
UgandaPresentNativeBruce (1999)
ZambiaPresentNativeBruce (1999)
ZimbabwePresent, Few occurrencesNativeBruce (1999)

Antarctica

South Georgia and the South Sandwich IslandsPresent, Few occurrencesNativeBruce (1999)

Asia

BahrainPresentNativeBruce (1999)
BangladeshPresentNativeBirdLife International (2012)
CambodiaPresentNativeBruce (1999)
ChinaPresentNativeBruce (1999)
-SichuanPresentNativeBirdLife International (2012)
-YunnanPresentNativeBruce (1999)
GeorgiaPresentNativeBirdLife International (2012)
IndiaPresent, WidespreadNativeKonig and Weick (2010)
-Andaman and Nicobar IslandsPresentNativeKonig and Weick (2010)
-Andhra PradeshPresentNativeKonig and Weick (2010)
-Arunachal PradeshPresentNativeKonig and Weick (2010)
-AssamPresentNativeKonig and Weick (2010)
-BiharPresentNativeKonig and Weick (2010)
-ChandigarhPresentNativeKonig and Weick (2010)
-ChhattisgarhPresentNativeKonig and Weick (2010)
-Dadra and Nagar HaveliPresentNativeKonig and Weick (2010)
-Daman and DiuPresentNativeKonig and Weick (2010)
-DelhiPresentNativeKonig and Weick (2010)
-GoaPresentNativeKonig and Weick (2010)
-GujaratPresentNativeKonig and Weick (2010)
-HaryanaPresentNativeKonig and Weick (2010)
-Himachal PradeshPresentNativeKonig and Weick (2010)
-Jammu and KashmirPresentNativeKonig and Weick (2010)
-JharkhandPresentNativeKonig and Weick (2010)
-KarnatakaPresentNativeKonig and Weick (2010)
-KeralaPresentNativeKonig and Weick (2010)
-LakshadweepPresentNativeKonig and Weick (2010)
-Madhya PradeshPresentNativeKonig and Weick (2010)
-MaharashtraPresentNativeKonig and Weick (2010)
-ManipurPresentNativeKonig and Weick (2010)
-MeghalayaPresentNativeKonig and Weick (2010)
-MizoramPresentNativeKonig and Weick (2010)
-NagalandPresentNativeKonig and Weick (2010)
-OdishaPresentNativeKonig and Weick (2010)
-PunjabPresentNativeKonig and Weick (2010)
-RajasthanPresentNativeKonig and Weick (2010)
-SikkimPresentNativeKonig and Weick (2010)
-Tamil NaduPresentNativeKonig and Weick (2010)
-TripuraPresentNativeKonig and Weick (2010)
-Uttar PradeshPresentNativeKonig and Weick (2010)
-UttarakhandPresentNativeKonig and Weick (2010)
-West BengalPresentNativeKonig and Weick (2010)
IndonesiaPresent, WidespreadNativeBruce (1999)
-JavaPresentNativeKonig and Weick (2010)
-Lesser Sunda IslandsPresentNativeBruce (1999);
-SumatraPresentNativeKonig and Weick (2010)
IranPresentNativeKonig and Weick (2010)
IraqPresentNativeKonig and Weick (2010)
IsraelPresentNativeBirdLife International (2012)
LaosPresentNativeKonig and Weick (2010)
MalaysiaPresent, Few occurrences2002NativeWells (2007)
-Peninsular MalaysiaPresent, Few occurrences2002NativeWells (2007)
MyanmarPresentNativeKonig and Weick (2010)
NepalPresentNativeBirdLife International (2012)
OmanPresentNativeAvibase (2012)
PakistanPresentNativeKonig and Weick (2010)
QatarPresentNativeAvibase (2012)
Saudi ArabiaPresentNativeKonig and Weick (2010)
SingaporePresentNativeAvibase (2012)
Sri LankaPresentNativeKonig and Weick (2010)
SyriaPresentNativeBruce (1999)
ThailandPresent, Few occurrences2002NativeWells (2007)
TurkeyPresent, Widespread2010NativeKirwan (2010)Uncommon despite widespread distribution. One report in East Anatolia
United Arab EmiratesPresent, Few occurrencesNativePederson and Aspinall (2011)
VietnamPresentNativeKonig and Weick (2010)
YemenPresentNativeBruce (1999)

Europe

AlbaniaPresentNativeBruce (1999)
AndorraPresentNativeBruce (1999)
AustriaPresentNativeBruce (1999)
BelarusPresentNativeBruce (1999)
BelgiumPresentNativeBruce (1999)
Bosnia and HerzegovinaPresentNativeBruce (1999)
BulgariaPresentNativeGolemanski et al. (2011); Bruce (1999)
CroatiaPresentNativeBruce (1999)
CyprusPresentNativeBruce (1999)
CzechiaPresentNativeBruce (1999)
CzechoslovakiaPresentNativeBruce (1999)
Federal Republic of YugoslaviaPresentNativeBruce (1999)
DenmarkPresentNativeBruce (1999)
EstoniaPresent, Few occurrencesIUCN (2012)Vagrant
FinlandPresent, Few occurrencesIUCN (2012)Vagrant
FrancePresentNativeBruce (1999)
-CorsicaPresentNativeBruce (1999)
GermanyPresentNativeBruce (1999)
GibraltarPresentNativeBruce (1999)
GreecePresentNativeBruce (1999)
HungaryPresentNativeBruce (1999)
IrelandPresent, Widespread2004NativeParkin and Knox (2009)May be declining; nest box efforts underway showing success in recruiting breeding individuals
ItalyPresentNativeBruce (1999)
LatviaPresentNativeBruce (1999)
LiechtensteinPresentNativeBruce (1999)
LithuaniaPresentNativeBruce (1999)
LuxembourgPresentNativeBruce (1999)
MaltaPresentNativeBruce (1999)
MoldovaPresentNativeBruce (1999)
MonacoPresentNativeBruce (1999)
MontenegroPresentNativeBruce (1999)
NetherlandsPresentNativeBruce (1999)
North MacedoniaPresentNativeBruce (1999)
NorwayPresent, Few occurrencesIUCN (2012)Vagrant
PolandPresentNativeBruce (1999)
PortugalPresentNativeBruce (1999)
-MadeiraPresentNativeBruce (1999)
RomaniaPresentNativeBruce (1999)
RussiaPresentNativeBirdLife International (2012)
San MarinoPresentNativeBruce (1999)
SerbiaPresentNativeBruce (1999)
Serbia and MontenegroPresentNativeBruce (1999)
SlovakiaPresentNativeBruce (1999)
SloveniaPresentNativeBruce (1999)
SpainPresentNativeBruce (1999)
-Balearic IslandsPresentNativeBruce (1999)
-Canary IslandsPresent, LocalizedNativeBruce (1999)
Svalbard and Jan MayenPresent, Few occurrencesBruce (1999)Vagrant
SwitzerlandPresentNativeBruce (1999)
UkrainePresentNativeBruce (1999)
United KingdomPresent, WidespreadNativeParkin and Knox (2009)May be declining; nest box efforts underway showing success in recruiting breeding individuals
-Channel IslandsPresentNativeBruce (1999)

North America

BahamasPresentNativeLong (1981); Marti et al. (2005)Colonized historically
BelizePresentNativeBruce (1999)
BermudaPresentNativeBruce (1999)
CanadaPresent, Localized1997NativeBruce (1999)
-British ColumbiaPresent, Few occurrences1997NativeCampbell et al. (1997)Present in southern portion of province in low numbers
-OntarioPresent, Few occurrences1997NativeCampbell et al. (1997)Present in southern portion of province in low numbers
-YukonPresent, Few occurrencesSinclair et al. (2003)Not reported in species list
Cayman IslandsPresentNativeBruce (1999)
Costa RicaPresentNativeBruce (1999)
CubaPresentNativeBruce (1999)
CuraçaoPresentNativeBruce (1999)
El SalvadorPresentNativeBruce (1999)
GuatemalaPresentNativeBruce (1999)
HondurasPresentNativeBruce (1999)
JamaicaPresentNativeBruce (1999)
MexicoPresent, WidespreadNativeBruce (1999)
Netherlands AntillesPresentNativeBruce (1999)
NicaraguaPresentNativeBruce (1999)
PanamaPresentNativeBruce (1999)
Trinidad and TobagoPresentNativeBruce (1999)
United StatesPresent, WidespreadNativeMarti et al. (2005)
-AlabamaPresentNativeMarti et al. (2005)
-ArizonaPresentNativeMarti et al. (2005)
-ArkansasPresentNativeMarti et al. (2005)
-CaliforniaPresent, WidespreadNativeMarti et al. (2005)
-ColoradoPresentNativeMarti et al. (2005)
-ConnecticutPresent, Few occurrencesNativeMarti et al. (2005)Endangered at the state level
-DelawarePresentNativeMarti et al. (2005)
-District of ColumbiaPresentNativeMarti et al. (2005)
-FloridaPresentNativeMarti et al. (2005)
-GeorgiaPresentNativeMarti et al. (2005)
-HawaiiPresent, Widespread2012Introduced1958Klavitter (2009)
-IdahoPresent, Few occurrencesNativeMarti et al. (2005)
-IllinoisPresent, Few occurrencesNativeMarti et al. (2005)Endangered at the state level
-IndianaPresent, Few occurrencesNativeMarti et al. (2005)
-IowaPresent, LocalizedNativeMarti et al. (2005)Endangered at the state level
-KansasPresentNativeMarti et al. (2005)
-KentuckyPresentNativeMarti et al. (2005)
-LouisianaPresentNativeMarti et al. (2005)
-MainePresent, Few occurrencesNativeMarti et al. (2005)
-MarylandPresentNativeMarti et al. (2005)
-MassachusettsPresent, LocalizedNativeMarti et al. (2005)Species of special concern
-MichiganPresent, Few occurrencesNativeMarti et al. (2005)Endangered at the state level
-MinnesotaPresent, Few occurrencesNativeMarti et al. (2005)Species of special concern
-MississippiPresentNativeMarti et al. (2005)
-MissouriPresent, Few occurrencesNativeMarti et al. (2005)Endangered at the state level
-NebraskaPresentNativeMarti et al. (2005)Species of special concern
-NevadaPresentNativeMarti et al. (2005)
-New HampshirePresent, Few occurrencesNativeMarti et al. (2005)
-New JerseyPresentNativeMarti et al. (2005)Species of special concern
-New MexicoPresentNativeMarti et al. (2005)
-New YorkPresent, LocalizedNativeMarti et al. (2005)Species of special concern
-North CarolinaPresentNativeMarti et al. (2005)
-North DakotaPresent, Few occurrencesNativeMarti et al. (2005)Species of special concern
-OhioPresent, Few occurrencesNativeMarti et al. (2005)Endangered at the state level
-OklahomaPresent, LocalizedNativeMarti et al. (2005)
-OregonPresent, LocalizedNativeMarti et al. (2005)Threatened at the state level
-PennsylvaniaPresent, Few occurrencesNativeMarti et al. (2005)Species at risk
-Rhode IslandPresentNativeMarti et al. (2005)
-South CarolinaPresentNativeMarti et al. (2005)
-South DakotaPresent, Few occurrencesNativeMarti et al. (2005)Species of special concern
-TennesseePresentNativeMarti et al. (2005)Species at risk
-TexasPresentNativeMarti et al. (2005)
-UtahPresent, Few occurrencesNativeMarti et al. (2005)
-VermontPresent, Few occurrencesNativeMarti et al. (2005)
-VirginiaPresentNativeMarti et al. (2005)
-WashingtonPresent, LocalizedNativeMarti et al. (2005)
-West VirginiaPresentNativeMarti et al. (2005)
-WisconsinPresent, Few occurrencesNativeMarti et al. (2005)Endangered at the state level
-WyomingPresent, Few occurrencesNativeMarti et al. (2005)

Oceania

American SamoaPresentNativeBruce (1999)
AustraliaPresentNativeLong (1981); Bruce (1999)Colonized in 1910
-New South WalesPresentNativeBruce (1999)
-Northern TerritoryPresentNativeBruce (1999)
-QueenslandPresentNativeBruce (1999)
-South AustraliaPresentNativeBruce (1999)
-TasmaniaPresentNativeBruce (1999)
-VictoriaPresentNativeBruce (1999)
-Western AustraliaPresentNativeBruce (1999)
FijiPresentNativeBruce (1999)
New CaledoniaPresentNativeBruce (1999)
New ZealandPresent, Few occurrencesHyde et al. (2013); Hyde et al. (2009)One breeding pair in recent years; means of arrival uncertain.
NiuePresentNativeBirdLife International (2012)
Papua New GuineaPresentNativeBruce (1999)
SamoaPresentNativeBruce (1999)
Solomon IslandsPresentNativeBruce (1999)
Timor-LestePresentNativeBruce (1999)
TongaPresentNativeBruce (1999)
VanuatuPresent, LocalizedNativeBruce (1999)

South America

ArgentinaPresentNativeBruce (1999)
BoliviaPresentNativeBruce (1999)
BrazilPresentNativeBruce (1999)
-AcrePresentNativeBruce (1999)
-AlagoasPresentNativeBruce (1999)
-AmapaPresentNativeBruce (1999)
-AmazonasPresentNativeBruce (1999)
-BahiaPresentNativeBruce (1999)
-CearaPresentNativeBruce (1999)
-Espirito SantoPresentNativeBruce (1999)
-Fernando de NoronhaPresentNativeBruce (1999)
-GoiasPresentNativeBruce (1999)
-MaranhaoPresentNativeBruce (1999)
-Mato GrossoPresentNativeBruce (1999)
-Mato Grosso do SulPresentNativeBruce (1999)
-Minas GeraisPresentNativeBruce (1999)
-ParaPresentNativeBruce (1999)
-ParaibaPresentNativeBruce (1999)
-ParanaPresentNativeBruce (1999)
-PernambucoPresentNativeBruce (1999)
-PiauiPresentNativeBruce (1999)
-Rio de JaneiroPresentNativeBruce (1999)
-Rio Grande do NortePresentNativeBruce (1999)
-Rio Grande do SulPresentNativeBruce (1999)
-RondoniaPresentNativeBruce (1999)
-RoraimaPresentNativeBruce (1999)
-Santa CatarinaPresentNativeBruce (1999)
-Sao PauloPresentNativeBruce (1999)
-SergipePresentNativeBruce (1999)
-TocantinsPresentNativeBruce (1999)
ChilePresentNativeBruce (1999)
ColombiaPresentNativeBruce (1999)
EcuadorPresentNativeBruce (1999)
Falkland IslandsPresent, Few occurrencesNativeBruce (1999)
French GuianaPresentNativeBruce (1999)
GuyanaPresentNativeBruce (1999)
ParaguayPresentNativeBruce (1999)
PeruPresentNativeBruce (1999)
SurinamePresentNativeBruce (1999)
UruguayPresentNativeBruce (1999)
VenezuelaPresentNativeBruce (1999)

History of Introduction and Spread

Top of page

T. alba was introduced to the Hawaiian Islands, USA, to control rats and mice causing damage to sugarcane plantations. During 1958-1963 the Hawaii Commissioners of Agriculture released 86 individuals from California and Texas. Although not an effective biocontrol agent, itbecame widespread throughout the state by 1966 (Foster, 2009).

T. alba was introduced to Mahé Island of the Seychelles in 1951-1952 with 27 individuals brought from South Africa. They were introduced to control the Black Rat (Rattus rattus), but failed to control rat populations. Except for an unsuccessful introduction on Isle Platt in 1949, T. alba established and spread throughout the islands and became abundant due to high availability of native seabird chicks (Lever, 2010).

T. alba was also introduced to Saint Helena Island in the South Atlantic around 1937 and is established there (Long, 1981), but little information is available regarding impacts and current population on the island.

The species was unsuccessfully introduced to New Zealand in 1899 and Lord Howe Island (Australia) during 1922-1950, in both cases for control of introduced, invasive rats (Long, 1981).

Introductions

Top of page
Introduced toIntroduced fromYearReasonIntroduced byEstablished in wild throughReferencesNotes
Natural reproductionContinuous restocking
Hawaii USA 1958-1963 Biological control (pathway cause) Yes Klavitter (2009); Pitt and Witmer (2007) Widespread across state; population size unknown
Saint Helena   Yes Long (1981)
Seychelles South Africa 1951-1952 Biological control (pathway cause) Yes Lever (2010); Long (1981) Control efforts have reduced population size on several islands

Risk of Introduction

Top of page

Intentional introduction is the only documented form of introduction; unintentional introduction is unlikely to occur, given the large size of this raptor (although according to Hyde et al. (2013), some individuals are known or suspected to have reached New Zealand as stowaways on aircraft or ships). T. alba is among the most cosmopolitan raptor species, and occurs throughout much of the world.  Extensive literature examining the impacts of T. alba on native species and its limited ability to control small mammal populations make future introduction of this species very unlikely.

Habitat

Top of page

T. alba is a generalist species residing in nearly all climes worldwide except the Sahara Desert, heavily forested or mountainous areas, and locations with mean winter temperatures significantly below 0°C (Bruce, 1999).  It prefers grasslands, deserts, marshlands and wetlands, agricultural areas, other open lowland areas and human-modified landscapes (Bruce, 1999; Marti et al., 2005).

Habitat List

Top of page
CategorySub-CategoryHabitatPresenceStatus
Multiple
Terrestrial
 
Terrestrial – ManagedCultivated / agricultural land Principal habitat Natural
Managed forests, plantations and orchards Principal habitat Natural
Managed grasslands (grazing systems) Principal habitat Natural
Disturbed areas Principal habitat Natural
Rail / roadsides Secondary/tolerated habitat Natural
Urban / peri-urban areas Secondary/tolerated habitat Natural
Buildings Secondary/tolerated habitat Natural
Terrestrial ‑ Natural / Semi-naturalNatural grasslands Principal habitat Natural
Riverbanks Principal habitat Natural
Wetlands Principal habitat Natural
Scrub / shrublands Secondary/tolerated habitat Natural
Deserts Principal habitat Natural
Littoral
Coastal areas Present, no further details Natural
Coastal dunes Present, no further details Natural
Salt marshes Present, no further details Natural

Biology and Ecology

Top of page

Genetics

T. alba has ninety-two diploid chromosomes (Belterman and Boer, 1984).

The number of subspecies is unresolved and several may constitute distinct species from T. alba.

Reproductive Biology

T. alba mates for life, although pairs roost separately until nesting begins (Ehrlich et al., 1982; Marti et al., 2005). It uses natural and manmade cavities for nesting, except for one report of nest burrowing in Colorado and New Mexico, USA (Millsap and Millsap, 1987; Bruce, 1999). The primary breeding season in the northern hemisphere occurs in March-July, although nests are documented throughout the year in various regions of North America. Flexible reproductive timing allows for adaptation to small mammal population fluctuations, and the timing of nesting likely occurs for the fledgling stage to correspond with peak numbers of prey (Marti et al., 2005). Two to three clutches may be laid during periods with large rodent populations (Konig and Weick, 2010). Clutch size is typically 4-7 eggs, but reportedly ranges from 2-16 during periods of reduced or greater prey abundance (Bruce, 1999). The incubation period, at least in the UK, is typically about 32 days and the fledging period 53-61 days (Robinson, 2013). Moulting follows breeding from July-September in the northern hemisphere (Marti et al., 2005).

Physiology and Phenology

There are no documented physiological differences in T. alba populations between native and introduced ranges. Females may abstain from nesting during periods of reduced prey abundance and during cold winters, and nestling reduction has been observed in experimental manipulations (Roulin et al., 1999; Marti et al., 2005). The species readily adapts to human environments and its common name originates from its frequent use of barns as roosting and nesting sites. High mortality caused by starvationis probably due to a high metabolism and inability to store sufficient fat reserves to persist through cold winters, which is uncommon among Tyto species (Marti et al., 2005).

Longevity

T. alba have a short lifespan of approximately 21 months owing to a variety of factors including cold temperatures and human-induced disturbance, with individuals eight years or more considered long-lived; the oldest in the wild was documented at 34 years of age (Marti et al., 2005; Lynch 2007). In the UK the typical lifespan is longer at about 4 years; the maximum recorded lifespan in the wild is 15 years (Robinson, 2013).

Activity Patterns

Migration by T. alba is known to occur primarily among juveniles and is dispersal-related. Adults are generally residents except at range limits, where they move to warmer climes for nesting and overwintering (Marti et al., 2005).

Population Size and Density

Population size is unknown and density varies greatly with habitat quality (Bruce, 1999; Marti et al., 2005). There is a general trend of decline in United States and across Europe, although no threat to the species is considered to exist given its widespread global distribution (BirdLife International, 2012). Active nest-box erection projects throughout the Midwest and Northeast USA provide additional nesting habitat and appear to be helping increase the population (Marti et al., 2005). Information regarding population size for individual subspecies is lacking.

Nutrition

A study conducted in Hawaii found non-native rodents present in 99.7% of pellets, birds in 15%, and insects in 1.3% (Snetsinger et al., 1994). Throughout the native range, the diet is highly variable and flexible and T. alba is not known to dramatically impact populations of threatened or endangered species (with one exception in the Seychelles -- see 'Impact: environmental' section). Voles are the predominant prey in North America and partially nocturnal small rodents are the primary prey worldwide. Small numbers of lagomorphs, mustelids, social-roosting and open-roosting passerines, seabirds, bats, and insects are taken as locally available (Long, 1981; Bruce, 1999; Bontzorlos et al., 2005; Marti et al., 2005; López-Ricardo and Borroto-Páez, 2012).

Note that the Natural Food Sources table refers only to species that have been recorded as prey items in the introduced range. A complete list for the whole range would include hundreds of species.

Environmental Requirements

T. alba is a cosmopolitan species limited by cold winters, with only vagrants reaching high northern and southern latitudes due to an inability to store sufficient fat stores for overwintering (Konig et al., 1999; Marti et al., 2005). The species generally occurs below 4000 m elevation (Bruce, 1999).

Natural Food Sources

Top of page
Food SourceFood Source DatasheetLife StageContribution to Total Food Intake (%)Details
Alauda arvensisAdult
Carpodacus mexicanusAdult
Gygis alba candidaAdult
Hemignathus virensAdult
Himatione sanguineaAdult
Leiothrix luteaAdult
Lonchura punctulataAdult
Mus musculusAdult
Myadestes obscurusAdult
Palmeria doleiAdult
Rattus exulansAdult
Rattus norvegicusAdult
Rattus rattusAdult

Climate

Top of page
ClimateStatusDescriptionRemark
A - Tropical/Megathermal climate Preferred Average temp. of coolest month > 18°C, > 1500mm precipitation annually
Am - Tropical monsoon climate Tolerated Tropical monsoon climate ( < 60mm precipitation driest month but > (100 - [total annual precipitation(mm}/25]))
As - Tropical savanna climate with dry summer Tolerated < 60mm precipitation driest month (in summer) and < (100 - [total annual precipitation{mm}/25])
Aw - Tropical wet and dry savanna climate Preferred < 60mm precipitation driest month (in winter) and < (100 - [total annual precipitation{mm}/25])
BS - Steppe climate Preferred > 430mm and < 860mm annual precipitation
BW - Desert climate Preferred < 430mm annual precipitation
C - Temperate/Mesothermal climate Preferred Average temp. of coldest month > 0°C and < 18°C, mean warmest month > 10°C
Cf - Warm temperate climate, wet all year Preferred Warm average temp. > 10°C, Cold average temp. > 0°C, wet all year
Cs - Warm temperate climate with dry summer Preferred Warm average temp. > 10°C, Cold average temp. > 0°C, dry summers
Cw - Warm temperate climate with dry winter Preferred Warm temperate climate with dry winter (Warm average temp. > 10°C, Cold average temp. > 0°C, dry winters)
D - Continental/Microthermal climate Preferred Continental/Microthermal climate (Average temp. of coldest month < 0°C, mean warmest month > 10°C)
Df - Continental climate, wet all year Tolerated Continental climate, wet all year (Warm average temp. > 10°C, coldest month < 0°C, wet all year)
Ds - Continental climate with dry summer Preferred Continental climate with dry summer (Warm average temp. > 10°C, coldest month < 0°C, dry summers)
Dw - Continental climate with dry winter Preferred Continental climate with dry winter (Warm average temp. > 10°C, coldest month < 0°C, dry winters)

Latitude/Altitude Ranges

Top of page
Latitude North (°N)Latitude South (°S)Altitude Lower (m)Altitude Upper (m)
58 55

Air Temperature

Top of page
Parameter Lower limit Upper limit
Mean annual temperature (ºC) 2 16
Mean maximum temperature of hottest month (ºC) 22 30
Mean minimum temperature of coldest month (ºC) -24 23

Natural enemies

Top of page
Natural enemyTypeLife stagesSpecificityReferencesBiological control inBiological control on
Bubo virginianus Predator Adults/Juveniles not specific

Notes on Natural Enemies

Top of page

Natural enemies do not appear to impact T. alba populations. Great Horned Owls (Bubo virginianus) have been reported to predate upon captive released T. alba in Iowa, USA, but there few reports of such predation in the wild (Ehresman, 1984; Marti et al., 2005). Adults are taken occasionally by a variety of large raptor species and nestlings are predated upon by snakes and stoats in North America (Marti et al., 2005). There is no reported predation by introduced or invasive species.

Means of Movement and Dispersal

Top of page

Natural Dispersal

T. alba historically colonized Bermuda, Australia, and Tasmania through flight and occurs as a vagrant to its latitudinal range limits (Long, 1981; Marti et al., 2005). Individuals are thought to have reached New Zealand in this way, although it is not certain that the recent records of nesting in New Zealand are a result of natural colonization (Hyde et al., 2013).

Accidental introduction

Some individuals are known or suspected to have reached New Zealand as stowaways on aircraft or ships (Hyde et al., 2013).

Intentional Introduction

T. alba was introduced as a biocontrol agent for invasive rodents on several islands of the Seychelles, throughout the Hawaiian Islands, on St. Helena, on Lord Howe Island (Australia), and in New Zealand (Long, 1981). It failed to establish on Lord Howe Island and New Zealand.

Pathway Causes

Top of page
CauseNotesLong DistanceLocalReferences
Biological controlTo reduce invasive rodent populations. Fewer than 100 individuals released on each occasion. Yes Bruce, 1999; Klavitter, 2009; Kowalsky et al., 2002; Long, 1981
HitchhikerOn ships and aircraft Yes Hyde et al., 2013
Self-propelledTo Bermuda, Australia and New Zealand Yes Hyde et al., 2009; Long, 1981; Marti et al., 2005

Impact Summary

Top of page
CategoryImpact
Cultural/amenity Positive
Economic/livelihood Positive
Environment (generally) Positive and negative

Environmental Impact

Top of page

Impact on Biodiversity

A local race of White Tern (Gygis alba candida) was nearly eliminated on Mahé Island, Seychelles, after introduction of T. alba as a biocontrol agent for invasive rodents. However, a successful reduction of the T. alba population has prevented further negative impacts (Lever, 2010). The species is known to take Magpie Robins (Copsychus sechellarum) (Long, 1981), and itcompetes with two native raptor species, the critically endangered Seychelles Scops owl (Otus insularis) and the vulnerable Seychelles Kestrel (Falco araea) (Lever, 2010).

Based on limited study, it appears that T. alba in Hawaii feeds primarily on rats and mice, but a small proportion of its diet may consist of native birds, with the proportion of birds in the diet greater than in Europe (Byrd and Telfer, 1980; Snetsinger et al., 1994; Kowalsky et al. 2002; Klavitter, 2009). There has been one reported incident of seabird take. The species is not known to consume the endangered Hawaiian Hoary bat, Lasiurus cinereus semotus (F. Bonnaccorso, Pacific Island Ecosystems Research Center, U.S. Geological Survey, Kilauea Field Station, Hawaii National Park, HI, USA, personal communication, 2012). The native Short-eared Owl or Pueo (Asio flammeus sandwichensis) is primarily diurnal and crepuscular; the extent to which T. alba competes with it for food and habitat is unknown (Riper and Scott, 2001; Pitt and Witmer, 2007).

Threatened Species

Top of page
Threatened SpeciesConservation StatusWhere ThreatenedMechanismReferencesNotes
Gygis alba candidaNo detailsSeychellesPredationLever, 2010; Long, 1981
Myadestes obscurusVU (IUCN red list: Vulnerable)HawaiiPredationSnetsinger et al., 1994
Palmeria dolei (crested honeycreeper)CR (IUCN red list: Critically endangered); USA ESA listing as endangered speciesHawaiiPredationBerlin and Vangelder, 1999

Risk and Impact Factors

Top of page Invasiveness
  • Proved invasive outside its native range
  • Has a broad native range
  • Abundant in its native range
  • Highly adaptable to different environments
  • Is a habitat generalist
  • Tolerant of shade
  • Capable of securing and ingesting a wide range of food
  • Highly mobile locally
  • Benefits from human association (i.e. it is a human commensal)
  • Has high reproductive potential
  • Has high genetic variability
Impact outcomes
  • Conflict
  • Reduced native biodiversity
  • Threat to/ loss of native species
Impact mechanisms
  • Interaction with other invasive species
  • Predation

Uses

Top of page

Economic Value

The economic value T. alba provides to agriculture through rodent predation is unquantified. Nevertheless, it may be of economic value by reducing rodent populations that cause damage to agricultural crops.

Uses List

Top of page

Environmental

  • Biological control

General

  • Sociocultural value

Detection and Inspection

Top of page

The distinctive flight pattern and appearance of T. alba allow for sufficient detectability despite its fairly cryptic and nocturnal behaviours. Survey methods used to detect other nocturnal owl species (e.g. voice, pellets) may be used to detect and monitor T. alba.

Similarities to Other Species/Conditions

Top of page

The sister species T. glaucops may be confused with T. alba in North America, but is distinguishable by plumage (Marti et al., 2005). There is little overlap in appearance among other Tyto species beyond North America.

Prevention and Control

Top of page

Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.

Prevention

T. alba is unlikely to be used for biological control in the future due to its failure to reduce invasive rodent populations at places of introduction. Prevention of introduction will require minimum effort, as more effective agents are now available for rodent control.

Control

The most effective treatment to remove T. alba from islands in the Seychelles was a bounty system employed the the Department of Agriculture. Other removal efforts included box traps, playback calls, mist net capture and hunting with air rifles. The species persists on most islands, although the population is considered controlled, and has been eradicated from Aride and Cousin islands (Fanchette, 2012).

Gaps in Knowledge/Research Needs

Top of page

There is scope for long-term monitoring of T. alba populations in areas of introduction, although given the localized nature of T. alba as an introduced species and previous successful efforts to reduce the Seychelles Islands population, extensive monitoring may not be warranted. Research may be needed to protect current populations and preserve subspecies diversity due to recent declines of the species across North America and Europe.

References

Top of page

Ash J; Atkins J, 2010. Birds of Ethiopia and Eritrea. London, UK: A & C Black, 463 pp.

Avibase, 2012. Avibase - the world bird database. http://avibase.bsc-eoc

Belterman RHR; Boer LEM De, 1984. A karyological study of 55 species of birds, including karyotypes of 39 species new to cytology. Genetica, 65(1):39-82.

Berlin KE; Vangelder EM, 1999. Akohekohe (Palmeria dolei). The Birds of North America Online [ed. by Poole, A.]. Ithaca, New York, USA: Cornell Lab of Ornithology, unpaginated. http://bna.birds.cornell.edu/bna/species/400

BirdLife International, 2012. Tyto alba. In: IUCN Red List of Threatened Species, Version 2012.1. http://www.iucnredlist.org

Bontzorlos VA; Peris SJ; Vlachos CG, 2005. The diet of Barn owl in the agricultural landscapes of central Greece. Folia Zoologica, 54(1-2):99-110.

Bowler J; Betts M; Bullock I; Ramos JA, 2002. Trends in Seabird Numbers on Aride Island Nature Reserve, Seychelles 1988-2000. In: Waterbirds, 25(1). 26-38.

Brooks J, 1991. The enigmatic owl. American Birds, 45(3):382-387.

Bruce MD, 1999. Family Tytonidae (Barn-owls). In: Handbook of the birds of the world. Vol. 5: Barn-owls to Hummingbirds [ed. by Hoyo, J. del \Elliott, A. \Sargatal, J.]. Barcelona, Spain: Lynx Edicions, 34-75.

Bunn DS; Warburton AB; Wilson RDS, 1982. The Barn Owl. Vermillion, South Dakota, USA: Buteo Books, 264 pp.

Byrd GV; Telfer TC, 1980. Barn owls prey on birds in Hawaii. 'Elepaio, 41(1):35-36.

Campbell RW; Dawe NK; McTaggart-Cowan I, 1997. Birds of British Columbia Volume 2: nonpasserines: diurnal birds of prey through woodpeckers. Vancouver, BC, Canada: UBC Press, 635 pp.

Dickinson E, 2003. The Howard and Moore complete checklist of the birds of the world, 3rd edn. London, UK: Christopher Helm, 1039 pp.

Eaton MA; Brown AF; Noble DG; Musgrove AJ; Hearn RD; Aebischer NJ; Gibbons DW; Evans A; Gregory RD, 2009. The population status of birds in the United Kingdom, Channel Islands, and Isle of Man. British Birds, 102(6):296-341.

Ehresman BL, 1984. Common barn-owl restoration in Iowa. Wildlife Rehabilitation [Proceedings of the National Rehabilitation Symposium], 3:10-19.

Ehrlich PR; Dobkin DS; Wheye D, 1988. The birder's handbook: a field guide to the natural history of North American birds. New York, USA: Simon & Schuster Inc, 785 pp.

Fanchette R, 2012. Invasive alien species: threat to biodiversity and human well-being. Seychelles strategy. Paris, France: IUCN France, unpaginated. http://www.especes-envahissantes-outremer.fr/pdf/atelier_ocean_Indien_2012/Seychelles.pdf

Foster JT, 2009. The history and impact of introduced birds. In: Conservation biology of Hawaiian forest birds: Implications for island avifauna [ed. by Pratt, T. K. \Atkinson, C. T. \Banko, P. C. \Jacobi, J. D. \Woodworth, B. L.]. New Haven, Connecticut, USA: Yale University Press, 312-330.

Golemanski V; Stoev P; Dobrev D; Beron; P; Zhivkov M; Popov A; Popov V; Beschkov V; Deltshev C; Michev T; Spassov N, 2011. Red Data Book of the Republic of Bulgaria (digital edition): Volume 2 - Animals. Red Data Book of the Republic of Bulgaria (digital edition): Volume 2 - Animals. Sofia, Bulgaria: Bulgarian Academy of Sciences and Ministry of Environment and Water. http://e-ecodb.bas.bg/rdb/en/vol2/

Hyde NHS; Matthews K; Seaton R, 2013. Barn Owl. In: New Zealand Birds Online: the digital encyclopaedia of New Zealand birds [ed. by Miskelly, C. M.]. http://www.nzbirdsonline.org.nz/species/barn-owl

Hyde NHS; Matthews K; Thompson M; Gale R, 2009. First record of Barn owls (Tyto alba) breeding in the wild in New Zealand. Notornis, 56(4):169-175.

IUCN, 2012. IUCN Red List of Threatened Species. Version 2012.2. www.iucnredlist.org/

Kirwan G, 2010. Birds of Turkey. London, UK: A & C Black, 512 pp.

Klavitter JL, 2009. The ecology and conservation of Hawaiian raptors. In: Conservation biology of Hawaiian forest birds: implications for island avifauna [ed. by Pratt, T. K. \Atkinson, C. T. \Banko, P. C. \Jacobi, J. D. \Woodworth, B. L.]. New Haven, Connecticut, USA: Yale University Press, 293-311.

Konig C; Weick F, 2010. Owls of the world: second edition. London, UK: A & C Black, 529 pp.

Konig C; Weick F; Becking JH, 1999. Owls: a guide to the owls of the world. New Haven, Connecticut, USA: Yale University Press, 462 pp.

Kowalsky JR; Pratt TK; Simon JC, 2002. Prey taken by feral cats (Felis catus) and Barn Owls (Tyto alba) in Hanawi Natural Area Reserve, Maui, Hawaii. 'Elepaio, 62(5):127-130.

Lever C, 2010. Naturalised birds of the world. London, UK: A & C Black, 352 pp.

Long JL, 1981. Introduced birds of the world: the worldwide history, distribution and influence of birds introduced to new environments. New York, USA: Universe Books, 528 pp.

López-Ricardo Y; Borroto-Páez R, 2012. Feeding of the Barn Owl (Tyto alba furcata) in central Cuba: introduced and native prey (Alimentación de la Lechuza (Tyto alba furcata) en Cuba central: Presas introducidas y autóctonas). Havana, Cuba: University of Havana, 86 pp.

Lynch W, 2007. Owls of the United States and Canada: a complete guide to their biology and behavior. Baltimore, MD, USA: John Hopkins University Press, 242 pp.

Marti CD; Poole AF; Bevier LR, 2005. Barn Owl (Tyto alba). The birds of North America online [ed. by Poole, A.]. http://bna.birds.cornell.edu/bna/species/001

Mikkola H, 1983. Owls of Europe. Waterhouses, UK: T & AD Poyser, 397 pp.

Millsap BA; Millsap PA, 1987. Burrow nesting by common Barn-owls in North Central Colorado. Condor, 89(3):668-670.

Mullarney K; Svennson L; Zetterstrom D; Grant PJ, 1999. Collins bird guide, vol. 2. UK, HarperCollins Publishers Ltd: London, 392 pp.

Parkin D; Knox A, 2009. Status of birds in Britain and Ireland. London, UK: A & C Black, 440 pp.

Pederson T; Aspinall SJ, 2011. EBRC Annotated checklist of the birds of the United Arab Emirates. Abu Dhabi, United Arab Emirates: EAD, 91 pp.

Pitt WC; Witmer GW, 2007. Invasive predators: a synthesis of the past, present, and future. In: Predation in organisms - a distinct phenomenon [ed. by Elewa, A. M. T.]. Heidelberg, Germany: Springer Verlag, 265-293.

Riper C van; III; Scott JM, 2001. Limiting factors affecting Hawaiian native birds. Studies in Avian Biology 22, 22:221-233.

Robinson RA, 2013. BirdFacts: profiles of birds occurring in Britain & Ireland. Thetford, UK: British Trust for Ornithology. [BTO Research Report 407.] http://www.bto.org/birdfacts

Roulin A; Ducrest AL; Dijkstra C, 1999. Effect of brood size manipulations on parents and offspring in the Barn Owl Tyto alba. Ardea, 87(1):91-100.

Sinclair PH; Nixon WA; Eckert CD, 2003. Birds of the Yukon Territory. Vancouver, BC, Canada: UBC Press, 595 pp.

Snetsinger TJ; Fancy SG; Simon JC; Jacobi JD, 1994. Diets of owls and feral cats in Hawaii. 'Elepaio, 54(8):47-49.

Soewu DA, 2008. Wild animals in ethnozoological practices among the Yorubas of southwestern Nigeria and the implications for biodiversity conservation. African Journal of Agricultural Research, 3(6):421-427. http://www.academicjournals.org/ajar/PDF/pdf%202008/Jun/soewu.pdf

Stone CP; Anderson SJ, 1988. Introduced animals and Hawaii's natural area. In: Proceedings, Thirteenth Vertebrate Pest Conference, Monterey, California, 1-3 Mar. 1988. 134-140.

Taylor I, 1994. Barn Owls: predator-prey relationships and conservation. Cambridge, UK: Cambridge University Press, xvi + 304 pp.

Taylor IR, 1993. Age and sex determination of Barn owls Tyto alba alba. Ringing and Migration, 14(2):94-102.

Wells DR, 2007. The birds of the Thai-Malay Peninsula: passerines: Vol 2. London, UK: Christopher Helm.

Distribution References

Ash J, Atkins J, 2010. Birds of Ethiopia and Eritrea., London, UK: A & C Black. 463 pp.

Avibase, 2012. Avibase - the world bird database., http://avibase.bsc-eoc

BirdLife International, 2012. (Tyto alba). In: IUCN Red List of Threatened Species, Version 2012, http://www.iucnredlist.org

Bruce MD, 1999. Family Tytonidae (Barn-owls). In: Handbook of the birds of the world. Vol. 5: Barn-owls to Hummingbirds, 5 [ed. by Hoyo J del, Elliott A, Sargatal J]. Barcelona, Spain: Lynx Edicions. 34-75.

CABI, Undated. CABI Compendium: Status as determined by CABI editor. Wallingford, UK: CABI

Campbell RW, Dawe NK, McTaggart-Cowan I, 1997. Birds of British Columbia Volume 2: nonpasserines: diurnal birds of prey through woodpeckers., 2 Vancouver, BC, Canada: UBC Press. 635 pp.

Golemanski V, Stoev P, Dobrev D, Beron, P, Zhivkov M, Popov A, Popov V, Beschkov V, Deltshev C, Michev T, Spassov N, 2011. Red Data Book of the Republic of Bulgaria (digital edition): Animals. In: Red Data Book of the Republic of Bulgaria (digital edition): Animals, 2 Sofia, Bulgaria: Bulgarian Academy of Sciences and Ministry of Environment and Water. http://e-ecodb.bas.bg/rdb/en/vol2/

Hyde NHS, Matthews K, Seaton R, 2013. Barn Owl. In: New Zealand Birds Online: the digital encyclopaedia of New Zealand birds, [ed. by Miskelly CM]. http://www.nzbirdsonline.org.nz/species/barn-owl

Hyde NHS, Matthews K, Thompson M, Gale R, 2009. First record of Barn owls (Tyto alba) breeding in the wild in New Zealand. In: Notornis, 56 (4) 169-175.

IUCN, 2012. IUCN Red List of Threatened Species. Version 2012.2., http://www.iucnredlist.org/

Kirwan G, 2010. Birds of Turkey., London, UK: A & C Black. 512 pp.

Klavitter JL, 2009. The ecology and conservation of Hawaiian raptors. In: Conservation biology of Hawaiian forest birds: implications for island avifauna, [ed. by Pratt TK, Atkinson CT, Banko PC, Jacobi JD, Woodworth BL]. New Haven, Connecticut, USA: Yale University Press. 293-311.

Konig C, Weick F, 2010. Owls of the world: second edition., London, UK: A & C Black. 529 pp.

Lever C, 2010. Naturalised birds of the world., London, UK: A & C Black. 352 pp.

Long JL, 1981. Introduced birds of the world: the worldwide history, distribution and influence of birds introduced to new environments., New York, USA: Universe Books. 528 pp.

Marti CD, Poole AF, Bevier LR, 2005. Barn Owl (Tyto alba). In: The birds of North America online, [ed. by Pool A]. http://bna.birds.cornell.edu/bna/species/001

Parkin D, Knox A, 2009. Status of birds in Britain and Ireland., London, UK: A & C Black. 440 pp.

Pederson T, Aspinall SJ, 2011. EBRC Annotated checklist of the birds of the United Arab Emirates., Abu Dhabi, United Arab Emirates: EAD. 91 pp.

Sinclair PH, Nixon WA, Eckert CD, 2003. Birds of the Yukon Territory., Vancouver, BC, Canada: UBC Press. 595 pp.

Wells D R, 2007. The birds of the Thai-Malay Peninsula: passerines, Vol. 2. London, UK: Christopher Helm.

Links to Websites

Top of page
WebsiteURLComment
Birds of North America Onlinehttp://bna.birds.cornell.edu/bna
British Trust for Ornithologyhttp://www.bto.org/
GISD/IASPMR: Invasive Alien Species Pathway Management Resource and DAISIE European Invasive Alien Species Gatewayhttps://doi.org/10.5061/dryad.m93f6Data source for updated system data added to species habitat list.
Global register of Introduced and Invasive species (GRIIS)http://griis.org/Data source for updated system data added to species habitat list.
IUCN Red Listhttp://www.redlist.org
New Zealand Birds Onlinehttp://nzbirdsonline.org.nz/
The Owl Pageshttp://www.owlpages.com

Organizations

Top of page

Switzerland: International Union for Conservation of Nature (IUCN), IUCN Conservation Centre Rue Mauverney 28, 1196, Gland, www.iucn.org

UK: BirdLife International, Wellbrook Court Girton Road, Cambridge CB3 0NA, http://www.birdlife.org

UK: BTO (British Trust for Ornithology), The Nunnery, Thetford, Norfolk, IP24 2PU, http://www.bto.org/

Contributors

Top of page

18/09/2012: Original text by:

Christina Leopold, Hawaii Cooperative Studies Unit, PO Box 10029 Hilo, HI 96721, USA.

Distribution Maps

Top of page
You can pan and zoom the map
Save map