Geographic Range
Cloud-forest screech owls (
Otus marshalli
) are endemic to South America, and are dispersed in the Andes Mountains of south
central Peru and Bolivia. These owls were first thought to occur on only three concentrated
areas in Pasco and northern Peru, in the northern region of Cusco. New studies have
projected that range to be larger. This includes alienated subpopulations of the Bolivian
Andes located in the northern area of La Paz, into Departamento Conchabambo, as well
as the Departmento Pasco. This information may be biased, as much of the joining land
between the populations is unstudied. Other recent modeling suggests the populations
are more continuous than originally thought.
- Biogeographic Regions
- neotropical
Habitat
The chief habitat of
Otus marshalli
is the canopy of the dense cloud forest of Cordillera Vilcabamb. These are forests
covered by mist, or low-level clouds. They experience a great deal of rainfall especially
during the wet season, and are covered in moss and epiphytes. The forest consists
of trees topping out at 40 m with a jagged canopy. Tree ferns and climbing bamboo
sweep the forest as well with ferns, mosses, and orchids growing on trees. Light
penetrates into the understory fairly well. Cloud-forest screech owls have a range
of 12,709 square kilometers. They are found in elevations of 1,920 m and reaching
to 2,240 m, but are most abundant between 2,130 and 2,190 m.
- Habitat Regions
- tropical
- terrestrial
- Terrestrial Biomes
- rainforest
Physical Description
Cloud-forest screech owls are of average size for a screech owl, with a standard body
mass of around 115 g. Their length can be anywhere from 20 to 23 cm. Their wingspan
ranges from 151.5 to 164 mm. The abdomen pattern is made of slanting white spots contrasted
by black and rufous streaks and bars. This is sometimes regarded as “ocellated”.
Just above the abdomen, it has a buffy-tinted nuchal collar. Rufous, black rimmed
facial discs with a partially shrouded white coronal band are distinct. Their eye
color is a dark brown, and it boasts a greenish gray bill. The ear tufts are diminutive
and made of white feathers with rufous and black tips. The middle dorsal side of
the bird usually has four black, irregular, transverse bars against a chestnut base;
but the overall coloration is uniform judged against that of close relatives. The
outer part of the primaries and secondaries are banded yellowish-brown, with the inner
part of the primaries dusky for the total length, except for two pale bands situated
distally and have an insipid tawny tip. The tail of the owl is markedly banded rufous
and blackish. The black bands become less discrete toward the distal part of the
tail. The tarsi are feathered by rufous colored feathers, but the toes are left naked.
Males and females both share this coloration, but colors on the female are seemingly
less bold. Females also tend to be larger than males.
- Other Physical Features
- endothermic
- heterothermic
- bilateral symmetry
- Sexual Dimorphism
- female larger
- male more colorful
Reproduction
This information is not yet known for cloud-forest screech owls.
Much of the breeding behavior of cloud-forest screech owls is unknown. The breeding
season lasts from June to mid-August, but it is unknown how many broods are produced.
Young cloud-forest screech owls reach sexual maturity at 1 year of age.
- Key Reproductive Features
- iteroparous
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- oviparous
Parental investment for cloud-forest screech owls is unknown. Like all owl species, it can be assumed that the young are born altricial, feather-less and with eyes closed. When young are born this defenseless, it can also be assumed that a large parental investment is required to incubate, protect, and care for the chicks.
- Parental Investment
- altricial
-
pre-fertilization
- provisioning
-
protecting
- female
Lifespan/Longevity
Lifespan of cloud-forest screech owls has not been documented.
Behavior
Cloud-forest screech owls often do not fly from branch to branch, opting instead to
climb and weave around the branches and epiphytes. Few observations have been made
of the birds acting naturally, and their nocturnal habitats make it even more difficult
to observe. Researchers often play audio recordings of cloud-forest screech owl calls
to lure the birds in for observation. This method gives little reward, as the owls
may take several hours to approach the source of the calls. They are skulking birds,
and thus are very secretive and adept at remaining hidden in the thick rain forest
canopies.
Communication and Perception
Cloud-forest screech owls have a few different vocalizations. They produce a "longsong" consisting of incessant monotonic hoots, which begin hushed. The intensity then increases, and ceases suddenly or with a short reduction of intensity for the last couple of notes. Song times range from 2.4 to 9.5 seconds. The last half of the song is slower than the opening half. This owl also infrequently performs a trill-like song which is characteristically short with regular “ii” sounds. This lasts for 2 seconds, in which time, the owl produces up to 23 notes. Because of this species' wide range, songs of different regions have been found to differ slightly with Cordillera Yanachaga populations having a lower pitch than their Bolivian counterparts. Cloud-forest screech owls do respond to playbacks of recorded territorial calls, thus the birds must use calls to define their territory.
Other types of communication have not been studied at this point. Like all birds,
cloud-forest screech owls perceive their environment through auditory, tactile, visual,
and chemical stimuli.
- Communication Channels
- acoustic
Food Habits
Cloud-forest screech owls are seemingly insectivorous, as many insect remains have
been found in their pellets (feces). They most likely clamber around tree branches
in search of arthropods and insects.
- Primary Diet
- carnivore
- Animal Foods
- insects
- terrestrial non-insect arthropods
Predation
There have been no observations regarding predation on the cloud-forest screech owl.
- Anti-predator Adaptations
- cryptic
Ecosystem Roles
The specific roles of cloud-forest screech owls are not yet known, but they are most
likely in conjunction with similar owls of the region including the rufescent screech
owls (
Megascops ingens
), long-whiskered owlets (
Xenoglaux loweryi
) and rufous-banded owls (
Ciccaba albitarsis
). They likely impact the insect populations, and any additional dietary organisms,
they consume.
Economic Importance for Humans: Positive
There are no reported positive economic effects of cloud-forest screech owls for humans.
Economic Importance for Humans: Negative
There are no reported negative economic effects of cloud-forest screech owls for humans.
Conservation Status
Cloud-forest screech owls are listed as 'Near Threatened' under IUCN Red List criteria
due to their exceedingly small range, making it extremely vulnerable to dangers which
may occur in the future. The owls are currently believed to be uncommon locally,
but there are no concrete numbers on population size. Habitat loss due to deforestation
is likely the largest danger, as rainforests are constantly being logged for fuel,
agricultural fields, and urbanization.
Additional Links
Contributors
Nikki Panos (author), Florida State University, Emily DuVal (editor), Florida State University, Rachelle Sterling (editor), Special Projects.
- 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.
- 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.
- rainforest
-
rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.
- 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.
- heterothermic
-
having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.
- 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.
- altricial
-
young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.
- arboreal
-
Referring to an animal that lives in trees; tree-climbing.
- nocturnal
-
active during the night
- motile
-
having the capacity to move from one place to another.
- sedentary
-
remains in the same area
- acoustic
-
uses sound to communicate
- cryptic
-
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
- carnivore
-
an animal that mainly eats meat
- insectivore
-
An animal that eats mainly insects or spiders.
- 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).
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- oviparous
-
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
References
Herzog, S., S. Ewing, K. Evans, A. Maccormick, T. Valuqui, R. Bryce, M. Kessler, R. MacLeod. 2009. Vocalizations, Distribution, and Ecology of the Cloud-Forest Screech Owl (Megascops marshalli). The Wilson Journal of Ornithology , 121: 240-252.
Weske, J., J. Terborgh. 1981. Otus marshalli, A New Species of Screech-owl from Peru. The Auk , 98: 1-7.
del Hoyo, J., A. Elliot, J. Sargatal. 1999. Handbook of the Birds of the World. Vol. 5. Barn-owls to Hummingbirds . Barcelona: Lynx Edicions.
2007. Endemic Species Distributions on the East Slope of the Andes in Peru and Bolivia . Arlington, Virginia, USA: NatureServe.
2010. "Bird Life International" (On-line). Cloud-forest Screech-owl Megascops marshalli. Accessed February 11, 2010 at http://www.birdlife.org/datazone/species/index.html?action=SpcHTMDetails.asp&sid =2204&m=0# .