Animal Diversity Web

Ge­o­graphic Range

Strix vir­gata is widely dis­trib­uted through­out the Nearc­tic and Neotrop­ics, from north­ern Mex­ico to Brazil and Ar­gentina. ("Hand­book of the Birds of the World. Vol. 5. Barn-owls to Hum­ming­birds", 1999)

• Biogeographic Regions
• nearctic
• neotropical

Habi­tat

In­hab­it­ing el­e­va­tions be­tween sea level and 2500 me­ters, mot­tled owls are often quite abun­dant within their range. Their habi­tats are ex­ten­sive and di­verse; they can live in a wide va­ri­ety of for­est and thicket edge, trop­i­cal rain­for­est, dry thorn for­est, trop­i­cal low­land for­est, pine-oak wood­land, and humid ever­green jun­gle. They can also live in areas with scat­tered trees, often close to towns and vil­lages. ("Hand­book of the Birds of the World. Vol. 5. Barn-owls to Hum­ming­birds", 1999)

• Habitat Regions
• terrestrial

• Terrestrial Biomes
• forest
• rainforest

• Range elevation

  0 to 2500 m

  0.00 to 8202.10 ft

Phys­i­cal De­scrip­tion

Strix vir­gata in­di­vid­u­als are medium-sized owls with brown eyes. They are mostly dark ex­cept for light brown fa­cial mark­ings. Mot­tled owls have yel­low-grey to blue-grey bills and their toes are grey­ish-yel­low. Their dor­sal mark­ings are much less no­tice­able than the ver­ti­cal streaks on their chest and throat. They look larger than they are be­cause of their thick feath­ers. ("Hand­book of the Birds of the World. Vol. 5. Barn-owls to Hum­ming­birds", 1999; "A Dic­tio­nary of Birds", 1985)

In owls, fe­males are gen­er­ally larger than the males. This evo­lu­tion of a re­versed size di­mor­phism has been ex­plained in many dif­fer­ent ways. Re­searchers mea­sure body mass dur­ing the breed­ing sea­son, wing length, tail length, bill length, tarsal length, and foot span. Fe­male mot­tled owls weighed sig­nif­i­cantly more than males and have sig­nif­i­cantly longer wing chords. Strix vir­gata has the most not­i­ca­ble di­mor­phism yet doc­u­mented among owls. (; Ger­hardt and Ger­hardt, 1987)

• Other Physical Features
• endothermic
• homoiothermic
• bilateral symmetry

• Sexual Dimorphism
• female larger

• Range mass

  175 to 320 g

  6.17 to 11.28 oz

• Range length

  355 to 280 mm

  13.98 to 11.02 in

Re­pro­duc­tion

Mot­tled owls are monog­a­mous, nei­ther fe­male nor male have any in­volve­ment with other nest­ing birds be­sides their mate. (Ger­hardt, et al., 1994; "A Dic­tio­nary of Birds", 1985)

• Mating System
• monogamous

Strix vir­gata have smaller clutches than eco­log­i­cally sim­i­lar or closely re­lated species. This species usu­ally lays 1 to 2 eggs be­tween Feb­ru­ary and May. Mot­tled owls usu­ally nest in holes of trees, tops of bro­ken off palm and oc­ca­sion­ally in empty nests of other birds. (; Ger­hardt and Ger­hardt, 1987)

• Key Reproductive Features
• iteroparous
• seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• fertilization
• oviparous

• Breeding interval

  Mottled owls breed once yearly.

• Breeding season

  The breeding season occurs between February and May.

• Range eggs per season

  1 to 2

Fe­males in­cu­bate eggs while males find food and bring it back to the nest. Both males and fe­males care for the young. (Ger­hardt, et al., 1994; "A Dic­tio­nary of Birds", 1985)

• Parental Investment
• pre-hatching/birth
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • male
  • protecting
    • female
• pre-independence
  • provisioning
    • male
  • protecting
    • female

Lifes­pan/Longevity

There is no in­for­ma­tion avail­able re­gard­ing the lifes­pan of this species.

Be­hav­ior

Mot­tled owls are soli­tary and strictly noc­tur­nal. They roost in dense fo­liage by day and may be mobbed by small birds if de­tected. These owls spend their wak­ing hours hunt­ing, preen­ing, yawn­ing, stretch­ing, and comb­ing their heads with their claws. ("Hand­book of the Birds of the World. Vol. 5. Barn-owls to Hum­ming­birds", 1999)

• Key Behaviors
• arboreal
• flies
• glides
• nocturnal
• motile
• solitary
• territorial

Home Range

The home range of male S. vir­gata is 2.8 hectares. (Ger­hardt, et al., 1994)

Com­mu­ni­ca­tion and Per­cep­tion

This species uses an array of vo­cal­iza­tions, such as hoots, whis­tles, screeches, screams, purrs, snorts, chit­ters, and hisses. When a mot­tled owl hoots, it is often ter­ri­to­r­ial and as­so­ci­ated with court­ing. The males have a lower pitched hoot than fe­males. When faced with a threat, owls pro­duce click­ing noises with their tongues. As part of a mat­ing dis­play, owls have the abil­ity to clap their wings in flight. (Ger­hardt, 1991)

Mot­tled owls pro­duce an array of calls. Their ter­ri­to­r­ial call con­sists of a se­ries of deep hoots, sound­ing like "bru bru" and "bu bu bu" or cowooa­woo or keeooweeyo. They also have a whis­tled screech. Mot­tled owls have been ob­served to have an en­larged voice box which al­lows them to pro­duce low-pitched notes for their size. (Ger­hardt, 1991)

Owls have keen hear­ing and vi­sion in low-light sit­u­a­tions. They lack color vi­sion.

• Communication Channels
• visual
• acoustic

• Perception Channels
• visual
• tactile
• acoustic
• chemical

Food Habits

Strix vir­gata in­di­vid­u­als feed on a di­verse diet in­clud­ing large in­sects such as bee­tles, grasshop­pers, and cock­roaches. They also feed on small mam­mals, birds, snakes, lizards, sala­man­ders, and frogs. They are con­sid­ered op­por­tunis­tic feed­ers as they may be at­tracted to ar­ti­fi­cial lights. Mot­tled owls pri­mar­ily hunt from perches which can be found along a for­est edge. ("Hand­book of the Birds of the World. Vol. 5. Barn-owls to Hum­ming­birds", 1999)

Mot­tled owls have keen vi­sion, hear­ing, and ma­neu­ver­able flight, con­tribut­ing to their suc­cess as preda­tors. Al­though they lack color vi­sion, these owls can ro­tate their heads to see in dif­fer­ent di­rec­tions. These owls also have sen­si­tive ears that allow them to pin­point sound sources in total dark­ness. Still, their ranges of hear­ing are not wide and con­tain deaf spots. Their wing feath­ers have adapted to dampen sound dur­ing flight, so they can ap­proach their prey with­out being heard.

• Primary Diet
• carnivore
  • eats terrestrial vertebrates
  • insectivore

• Animal Foods
• birds
• mammals
• amphibians
• reptiles
• insects

Pre­da­tion

Owls are at the top of the food web. They have no major preda­tors. ("The Owl Pages: In­for­ma­tion about Owls", 2005; "Owl Facts", 2004)

Ecosys­tem Roles

This species is a gen­er­al­ist preda­tor, and po­ten­tially im­pacts many prey pop­u­la­tions. ("Hand­book of the Birds of the World. Vol. 5. Barn-owls to Hum­ming­birds", 1999)

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Mot­tled owls have been stud­ied by sci­en­tists and re­search has been pub­lished on their breed­ing be­hav­ior. They also help con­trol some ro­dent and in­sect pest pop­u­la­tions. ("The Food Habits of Sym­patric Ci­c­caba Owls in North­ern Guatemala.", 1994; Buchanan, 1971; Ger­hardt, 1991; Ger­hardt, et al., 1994; Wylie , 1976)

• Positive Impacts
• research and education
• controls pest population

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

There are no known ad­verse af­fects of Strix vir­gata on hu­mans.

Con­ser­va­tion Sta­tus

This wide­spread species is not glob­ally threat­ened. Strix vir­gata are con­sid­ered com­mon in many habi­tats and can be seen largely in pro­tected areas. ("Hand­book of the Birds of the World. Vol. 5. Barn-owls to Hum­ming­birds", 1999)

• IUCN Red List

  No special status
  More information

• IUCN Red List

  No special status
  More information

• US Migratory Bird Act

  No special status

• US Federal List

  No special status

• CITES

  Appendix II

Con­trib­u­tors

Matthew Wund (ed­i­tor), Uni­ver­sity of Michi­gan-Ann Arbor.

Jess Fet­ter (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor, Phil Myers (ed­i­tor), Mu­seum of Zo­ol­ogy, Uni­ver­sity of Michi­gan-Ann Arbor.

Ref­er­ences

The British Or­nithol­o­gists' Union. 1985. A Dic­tio­nary of Birds. South Dakota: Buteo Books.

1999. Hand­book of the Birds of the World. Vol. 5. Barn-owls to Hum­ming­birds. Barcelona: Lynx Edi­cions.

Birds of Prey Foun­da­tion. 2004. "Owl Facts" (On-line). Ac­cessed March 28, 2003 at http://​www.​birds-of-prey.​org/​educate/​owls.​htm.

1994. The Food Habits of Sym­patric Ci­c­caba Owls in North­ern Guatemala.. Jour­nal of Field Or­nithol­ogy, 65: 258-264.

Owl Pages. 2005. "The Owl Pages: In­for­ma­tion about Owls" (On-line). Ac­cessed Sep­tem­ber 22, 2004 at http://​www.​owlpages.​com/​species/​strix/​virgata/​Default.​htm.

Buchanan, M. 1971. The Mot­tled Owl Ci­c­caba Vir­gata in Trinidad.. Ibis, 113: 105-106.

Ger­hardt, , D. Ger­hardt. 1987. Size, Di­mor­spism, and Re­lated Char­ac­ter­is­tics of Ci­c­caba Owls From Guatemala. 2nd Owl Sym­po­sium: 190-196. Ac­cessed Sep­tem­ber 22, 2004 at http://​www.​ncrs.​fs.​fed.​us/​pubs/​gtr/​other/​gtr-nc190/​GERHARD.​PDF#​xml.

Ger­hardt, R. 1991. Re­sponse of Mot­tled Owls to Broad­cast of Con­spe­cific Call.. Jour­nal of Field Or­nithol­ogy, 62: 239-244.

Ger­hardt, R., D. Ger­hardt, C. Flat­ten. 1994. Breed­ing Bi­ol­ogy and Home Range of Two Ci­c­caba Owls. Wil­son Bul­letin, 106: 629-639.

Wylie , S. 1976. Breed­ing the Mot­tled Owl at the St. Louis Zoo. The Avi­cul­tural Mag­a­zine, 82: 64-65.