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Otus trichopsiswhiskered screech owl(Also: whiskered screech-owl)

By Jackson Lynch

Geographic Range

Otus trichopsis (whiskered screech-owl), is found from southeast Arizona and southwest New Mexico to northern Nicaragua, and it is found almost everywhere in between, provided there is suitable habitat. (Gehlbach and Gehlbach, 2000)

Habitat

Whiskered screech-owls are found in montane woodlands and forests as well as riparian canyon forests. They can be found at elevations between 1000 to 2900 m. (Gehlbach and Gehlbach, 2000)

  • Range elevation
    1000 to 2900 m
    3280.84 to 9514.44 ft

Physical Description

Whiskered screech-owls are small owls 17.5 to 18.9 cm long, weighing 85 to 98 g. They have prominent ear-tufts, yellow-olive bills, and feathered toes. They are usually grey with rusty tones (females are darker). A rufous morph and a brownish variant of grey occur, mostly in the Latin American portion of their range. Adults have distinct whisker-like extensions of facial disk feathers and a golden to orangish iris. (Gehlbach and Gehlbach, 2000)

  • Sexual Dimorphism
  • sexes colored or patterned differently
  • Range mass
    85 to 98 g
    3.00 to 3.45 oz
  • Range length
    17.5 to 18.9 cm
    6.89 to 7.44 in

Reproduction

Whiskered screech-owls are monogamous with pair bonds lasting at least one mating season. Copulation is preceeded by a female whistle which is accompanied by male telegraphic trill. There is no obvious courtship feeding. Each copulation lasts approximately five seconds. (Gehlbach and Gehlbach, 2000)

Breeding occurs in April and May. Females lay 2 to 4 eggs per clutch; eggs are incubated for 26 days, on average. Chicks fledge after 24 to 30 days. (Gehlbach and Gehlbach, 2000)

  • Breeding season
    April and May
  • Range eggs per season
    2 to 4
  • Average time to hatching
    26 days
  • Range fledging age
    24 to 30 days

Only female whiskered screech-owls incubate the eggs. Females stay on the eggs at all times except for brief recesses at dusk and before dawn. Males provision incubating females.

Young are semi-altricial with downy white feathers, bare pinkish skin, closed eyes, and an egg tooth. After twenty days their average mass is 75 grams. Males hunt and transfer food to females inside or outside the nest cavity while she is brooding. Females hunt when nestlings are one to two weeks old and are no longer brooded. Fledglings initially have weak flying skills and stay near the parents; they are closely attended by their parents in the first week. Fledglings begin to catch insects in two to three weeks but do poorly at first. They beg to parents and are fed for at least four weeks but probably longer. (Gehlbach and Gehlbach, 2000)

  • Parental Investment
  • no parental involvement
  • pre-hatching/birth
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • male
      • female
    • protecting
      • female
  • pre-independence
    • provisioning
      • male
      • female

Lifespan/Longevity

We do not have information on lifespan/longevity for this species at this time.

Behavior

Adults and fledglings walk and hop on the ground and also among tree branches. Whiskered screech-owls use rapid wing beats, brief glides, twists, and turns through trees in or below tree canopy. Adults are quite unaggressive unless aroused by unnatural stimuli such as decoys, persistant song imitations and tape playing (Marshall et al., 1991). Individuals may briefly chase neighbors, but mainly sing at or ignore them. Whiskered screech-owls are presumed to be asocial outside of breeding season.

Males defend more than one nest cavity. The size of the area defended around each cavity is related to tree density. Cavities that are not used as nest sites serve as roosts, food caches and replacement nest cavities. (Gehlbach and Gehlbach, 2000; Marshall, et al., 1991)

Home Range

We do not have information on home range for this species at this time.

Communication and Perception

Songs consist of multiple notes with intervals between notes. Intervals are normally less than twice the note duration and they have higher-frequency harmonics (Van der Weyden, 1975). Males also make a short trill that is three to fifteen notes and lasts 1.0 to 2.5 seconds (Jacot, 1931; Martin, 1974). The emphatic trill, a variant of the short trill, rises slightly to a louder third note then falls (Gehlbach and Gehlbach, 2000). (Gehlbach and Gehlbach, 2000; Jacot, 1931; Martin, 1974; Van der Weyden, 1975)

Food Habits

Whiskered screech-owls use a sit-and-wait strategy when hunting. They capture prey with their feet and bill. They find prey on foliage, tree trunks, leaf litter and the ground. Insects, including caterpillars, are their primary food, but their diet incorporates a variety of arthropods, lizards, snakes, birds, bats, shrews, and mice.

Whiskered screech-owls will cache food in unused nest cavities. (Gehlbach and Gehlbach, 2000)

  • Animal Foods
  • birds
  • mammals
  • reptiles
  • insects
  • terrestrial non-insect arthropods

Predation

Whiskered Screech-owl pairs bark at predators that come in the vicinity of their nest. The nest is vulnerable to gopher snakes (Pituophis melanoleucus), green rat snakes (Senticolis triaspis), coatis (genus Nasua) and raccoons (Procyon lotor). Spotted owls (Strix occidentalis) and Cooper's hawks (Accipiter cooperii) are known adult predators. (Gehlbach and Gehlbach, 2000)

Ecosystem Roles

Whiskered screech-owls have an impact on the prey they eat.

Economic Importance for Humans: Positive

We do not have information on economic importance for humans for this species at this time.

Economic Importance for Humans: Negative

There are no known adverse affects of whiskered screech-owls on humans.

Conservation Status

Whiskered screech-owls are threatened in New Mexico, because they are restricted to the Peloncillo-Guadalupe Mountains and in El Salvador because of habitat loss. They are protected under the US MBTA and are listed under Appendix II by CITES, but are not listed by the US ESA or the IUCN. (Komar, 1998)

Contributors

Alaine Camfield (editor), Animal Diversity Web.

Jackson Lynch (author), University of Arizona, Todd McWhorter (editor), University of Arizona.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

acoustic

uses sound to communicate

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

insectivore

An animal that eats mainly insects or spiders.

internal fertilization

fertilization takes place within the female's body

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

monogamous

Having one mate at a time.

motile

having the capacity to move from one place to another.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

stores or caches food

places a food item in a special place to be eaten later. Also called "hoarding"

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

visual

uses sight to communicate

References

Gehlbach, F., N. Gehlbach. 2000. Whiskered Screech-Owl (Otus trichopsis). Pp. 1-23 in A Poole, F Gill, A Poole, F Gill, eds. The Birds of North America, Vol. 507. The Academy of Natural Sciences, Philadelphia, and The American Ornithologist's Union, Washington, D.C.

Jacot, E. 1931. Notes on the Spotted and Flammulated screech-owls in Arizona. Condor, 33: 8-11.

Komar, O. 1998. Avian diversity in El-Salvador. Wilson Bulletin, 110(4): 511-533.

Marshall, J., R. Behrstock, C. Konig. 1991. Special review: voices of the New World owls, Strigiformes: Tytonidae, Strigidae by J.W. Hardey, B.B. Koffey Jr., G.B. Reynerd. Wilson Bulletin, 103: 311-314.

Martin, D. 1974. Copulatory and vocal behavior of a pair of whiskered owls. Auk, 91: 619-624.

Van der Weyden, W. 1975. Scops and screech owls: vocal evidence for a basic subdivision in the genus Otus (Strigidae). Ardea, 63: 66-77.

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