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.
- Biogeographic Regions
- nearctic
- neotropical
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.
- Habitat Regions
- temperate
- tropical
- terrestrial
- Other Habitat Features
- riparian
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.
- Other Physical Features
- endothermic
- bilateral symmetry
- Sexual Dimorphism
- sexes colored or patterned differently
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.
- Mating System
- monogamous
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.
- Key Reproductive Features
- iteroparous
- seasonal breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- fertilization
- oviparous
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.
- Parental Investment
- no parental involvement
-
pre-hatching/birth
-
protecting
- female
-
protecting
-
pre-weaning/fledging
-
provisioning
- male
- female
-
protecting
- female
-
provisioning
-
pre-independence
-
provisioning
- male
- female
-
provisioning
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.
- Key Behaviors
- flies
- nocturnal
- motile
- solitary
- territorial
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).
- Communication Channels
- acoustic
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.
- Primary Diet
-
carnivore
- eats terrestrial vertebrates
- insectivore
- Animal Foods
- birds
- mammals
- reptiles
- insects
- terrestrial non-insect arthropods
- Foraging Behavior
- stores or caches food
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.
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.
Additional Links
Contributors
Alaine Camfield (editor), Animal Diversity Web.
Jackson Lynch (author), University of Arizona, Todd McWhorter (editor), University of Arizona.
- 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.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- Neotropical
-
living in the southern part of the New World. In other words, Central and South America.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- 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).
- tropical
-
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
- terrestrial
-
Living on the ground.
- forest
-
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
- mountains
-
This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.
- riparian
-
Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).
- monogamous
-
Having one mate at a time.
- 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).
- 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
- fertilization
-
union of egg and spermatozoan
- internal fertilization
-
fertilization takes place within the female's body
- oviparous
-
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
- nocturnal
-
active during the night
- motile
-
having the capacity to move from one place to another.
- solitary
-
lives alone
- 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
- acoustic
-
uses sound to communicate
- stores or caches food
-
places a food item in a special place to be eaten later. Also called "hoarding"
- carnivore
-
an animal that mainly eats meat
- insectivore
-
An animal that eats mainly insects or spiders.
- 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.
- 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.
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
References
Gehlbach, F., N. Gehlbach. 2000. Whiskered Screech-Owl (Otus trichopsis). Pp. 1-23 in 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) 110: 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 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.