Megascops kennicottii

Western screech-owls (Otus kennicotti) inhabit western North America, northwestern Mexico and coastal regions of the Pacific Northwest (Cannings and Angell, 2001). Ranging as far north as southeast Alaska and southern Canada to the Baja penninsula and into Mexico, western screech-owls make their homes within the diverse communities of the riparian deciduous woodlands of North America (Cornell Lab of Ornithology, 1999). Within the last 40 years, the range of western screech-owls has expanded as far east as Texas (perhaps due to increased tree-planting) and as a result they are now found sympatrically with their very close relative, eastern screech-owls (Otus asio).

Biogeographic Regions: nearctic (Native )

Global Range: (20,000-2,500,000 square km (about 8000-1,000,000 square miles)) RESIDENT: from south-coastal and southeastern Alaska, coastal and southern British Columbia, northern Idaho, western Montana, southeastern Colorado and extreme western Oklahoma south to southern Baja California, northern Sinaloa, in Mexican highlands to Distrito Federal, and to western Texas (AOU 1998, Cannings and Angell 2001). Apparently has expanded north into southern Alberta.

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Otus kennicottii is a small owl with feathered "ear tufts". Adults are 19 to 25.5 cm in length; and weigh 170.1 g on average. Male wingspans are 168.4 mm, female wingspans are 174.5 mm. Sexes are alike in plumage characteristics. Plumage of western screech-owls is generally monomorphhic in a given area; brown or gray-brown in the northwest and gray in southern deserts. Some populations in the coastal regions of the Pacific Northwest are more variable in color, often displaying reddish-brown morphs (Cannings and Angell, 2001).

The face of western screech-owls is pale with a dark lateral border, their underparts are streaked and barred. They have yellow eyes and dark bills. Their feet and toes are feathered in northern populations but bristled in southern deserts (Cannings and Angell, 2001).

Range mass: 163.5 to 183 g.

Average mass: 170.1 g.

Range length: 19 to 25.5 cm.

Range wingspan: 168.4 to 174.5 mm.

Sexual Dimorphism: sexes alike; female larger

Length: 22 cm

Weight: 186 grams

Systems

• Terrestrial

Western screech-owls usually inhabit low elevation riparian and deciduous oak woodland commmunities (Campbell et al., 1990; Cannings, 1997; Cannings and Angell, 2001). They will often inhabit streamside groves, deserts, suburban parks and gardens (Cornell Lab of Ornithology, 1999). The abundance of O. kennicotti is positively associated with overstory cover of mesquite (prosopis) and understory cover of native perennial vegetation (Hardy et al., 1999).

Within the United States O. kennicottii occurs in high densities in the following regions:

Arizona: mesquite-riparian zones of the Sonoran Desert. In particular, western screech-owls are strongly associated with structurally diverse uplands of the Sonoran Desert, containing saguaros (Carnegiea gigantea), mesquite woodlands and cottonwood (Populus)-willow (Salix) riparian areas (Hardy et al., 1999).

Texas: lower elevations in riparian zones dominated by Arizona sycamore (Plantanus wrightii) as well as pure oak habitats (Gelbach and Leverett, 1995; Cannings and Angell, 2001).

California: western screech-owls are strongly associated with areas with fan palms (Washingtonia filifera) and oak woodlands (Feusier, 1989; Noble, 1990; Lehman, 1994; Cannings and Angell, 2001).

Washington and Alaska: western screech-owls are found in riparian habitats and the mixed forests of coastal regions consisting of big-leaf maple (Acer macrophyllum), red alder (Alnus rubra), Douglas fir (Psudotsuga menziesii), western hemlock (Tsuga heterophylla)and western red cedar (Thyja plicata) (Kitchin, 1949; Cannings and Angell, 2001).

Colorado: western screech-owls are primarily found in rural developed areas and areas with broad-leaved cottonwoods along river basins. They are also associated with farmyards containing mature, unpruned cottonwood trees and shrubbery. Throughout their range they are found in urban and suburban parks as well as residential areas (Levad, 1998; Cannings and Angell, 2001).

Habitat Regions: temperate ; terrestrial

Terrestrial Biomes: desert or dune ; forest

Aquatic Biomes: coastal

Other Habitat Features: suburban ; agricultural ; riparian

Comments: Woodland, especially broadleaf (e.g. oak) and riparian woodland, and scrub (Subtropical and Temperate zones) (AOU 1983). Also moist coniferous forest and woodland on northwest coast. Usually found at lower elevations, where in southwest range overlaps with Whiskered Screech-owl (National Geographic Society 1983).

Nests in natural tree cavity or an abandoned woodpecker hole, including holes in saguaro cactus. Readily nest in nest boxes.

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

In Rocky Mountains some individuals may descend to lower elevations or into more protected valleys for winter (Voous and Cameron 1989).

Western screech-owls are "sit-and-wait" predators. They leave their roosts to forage just before sunset. Their hunting technique may predispose the northern populations to primarily hunt mice. When foraging near bodies of water, O. kennicottii will perch and wait until crayfish emerge in the shallows, then it will fly down and grab one by dipping only its legs into the water. It will also hawk for flying insects and glean arthropods from folage, but it prefers to catch small, terrestrial mammals (Hayward and Garton, 1988; Cannings and Angell, 2001).

Songbirds are a frequent meal for O. kennicottii and as a result the owls are often mobbed in response to their threats. Frequent mobbers are those songbirds that are most often preyed upon (for example, northern cardinals and white-throated sparrows). Mobbing by songbirds occurs most frequently during the spring and early summer nesting period. Most mobbers are permanent residents that are always part of the avian prey community. Birds use seasonal song, age-realted plumage and nest-area cues of western screech-owls to help assess the danger of predation (Gehlbach and Leverett, 1995).

Western screech-owls commonly eat: small mammals, birds, annelid worms, insects, crayfish and fish.

Animal Foods: birds; mammals; fish; insects; terrestrial non-insect arthropods; terrestrial worms

Primary Diet: carnivore (Eats terrestrial vertebrates, Piscivore , Insectivore , Eats non-insect arthropods)

Comments: Feeds mainly on small mammals (mice and shrews), insects, birds; sometimes also other small vertebrates. Diet may vary seasonally and geographically, depending on local prey abundance.

Colonies of tree ants (genus Crematogaster) will often occupy the nest sites of Otus kennicottii and apparantly protect the nest from disturbance by biting or stinging potential predators. This relationship seems to be a unique symbiosis in the genus Otus, however, it is infrequent (McCallum et al., 1995).

The abundance of western screech-owls is positively associated with the abundance of elf owls (Micrathene whitneyi) in the Sonoran Desert (Hardy et al., 1999).

Mutualist Species:

• tree ants (genus Crematogaster)

Western screech-owls typically react to the presence of predators with bill snaps and bark calls.

Known predators include: spotted owls (Strix occidentalis), great horned owls (Bubo virginianus), barred owls (Strix varia), raccoons (Procyon lotor), gopher snakes (Pituophis melanoleucus) and crows and jays (family Corvidae).

Known Predators:

• spotted owls (Strix occidentalis)
• great horned owls (Bubo virginianus)
• barred owls (Strix varia)
• raccoons (Procyon lotor)
• gopher snakes (Pituophis melanoleucus)
• crows and jays (Corvidae)

Otus kennicottii is prey of:
Corvidae
Pituophis melanoleucus
Bubo virginianus
Strix varia
Strix occidentalis
Procyon lotor

This list may not be complete but is based on published studies.

Otus kennicottii preys on:
non-insect arthropods
Actinopterygii
Annelida
Arthropoda
Insecta
Aves
Mammalia

This list may not be complete but is based on published studies.

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 81 to >300

10,000 - 1,000,000 individuals

Comments: Canadian population estimated at 3000-10,000 individuals (Chaundy-Smart 2002); many more than this occur elsewhere in the range.

In central Idaho, home ranges of 2 radio-tagged birds reported as 3-9 ha and 29-58 ha based on 75% and 95% contour intervals, respectively. Distance between adjacent pairs ranges from ca. 50 up to a few hundred meters (see Johnsgard 1988).

The song of Otus kennicottii consists of 5 to 15 hollow whistle hoots of a single pitch that accelerate towards the end in a "bouncing ball" sequence (Cannings and Angell, 2001).

Communication Channels: acoustic

Development of young at age-

1 week: eyes open and egg tooth absent.

1-2 weeks: young bill snap in response to disturbance.

3 weeks: more aggressive, hissing and swaying with wings outstreched.

Reach fledgling state within approximately 35 days. For the first 5 weeks following fledging, juvenilles will remain in close association with thier parents and most probably begin breeding when 1 year old (Sumner 1929, Cannings and Angell 2001).

Western screech-owls usually live from 1 to 8 years in the wild. The longest recorded lifespan for a western screech-owl in the wild is 13 years, in captivity the longest recorded lifespan is 19 years.

Range lifespan
Status: wild: 13 (high) years.

Range lifespan
Status: captivity: 19 (high) years.

Typical lifespan
Status: wild: 1 to 8 years.

Maximum longevity: 19 years (captivity) Observations: In the wild, these animals may live up to 12.9 years (Clapp et al. 1983). Two captive birds lived to the age of 19 (http://bna.birds.cornell.edu/).

Otus kennicottii is usually monogomous, although polygamy occurs occasionally.

Before the breeding season, male O. kennicottii defend an area containing several nest cavities. Pair formation begins during the months of January and February throughout the range. Allopreening is an important part of continuous pair-bonding behavior and occurs at all times of the year. Courtship-feeding is common. The male will present food to the female and perform elaborate courtship displays involving bowing, bill snapping, and hopping.

Mating System: monogamous

Throughout its range, O. kennicottii will nest in tree cavities, most commonly those excavated by other species. Examples include: fox squirrels, northern flickers, gilded flickers, pileated woodpeckers and European starlings (Campbell et al., 1990; Cannings and Angell, 2001; Cornell Lab of Ornithology, 1999). They also inhabit natural tree cavites and nest boxes.

Eggs are laid during March and April. They are white and oval to broadly eliptical. Females lay 2 to 7 eggs per clutch (3 to 5 on average). Incubation lasts 26 to 34 days and the chicks fledge in 27 to 35 days.

Western screech-owls probably begin breeding when they are 1 year old, adults attempt to nest every year (Cannings and Angell, 2001).

Breeding interval: Western screech owls breed once yearly.

Breeding season: Eggs are laid in March or April.

Range eggs per season: 2 to 7.

Average eggs per season: 3.

Range time to hatching: 26 to 34 days.

Range fledging age: 29 to 35 days.

Average age at sexual or reproductive maturity (female): 1 years.

Average age at sexual or reproductive maturity (male): 1 years.

Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); fertilization (Internal )

Western screech-owls add no new material to the nest site, rather they use whatever substrate is already present. They prefer to nest in tree cavities or nest boxes. Cottonwood seems to be favored wherever available, most likely because of its tendency to form large natural cavities (Cannings and Angell, 2001).

Altricial nestlings are covered in white down when they hatch. Their eyes are closed and they have an egg tooth. Males will feed females throughout egg-laying, incubation and brooding periods until the young are about 3 weeks old (Cannings and Angell, 2001). Both males and females provide food for the nestlings (Cornell Lab of Ornithology, 1999; Ehrlich et al., 1988).

Parental Investment: no parental involvement; altricial ; pre-fertilization; pre-hatching/birth (Protecting: Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Female)

Clutch size averages 3-4. Incubation about 26 days.

The following is a representative barcode sequence, the centroid of all available sequences for this species.

There are 9 barcode sequences available from BOLD and GenBank.  Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.  See the BOLD taxonomy browser for more complete information about this specimen and other sequences.

Download FASTA File

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 9
Specimens with Barcodes: 12
Species With Barcodes: 1

Year Assessed

Assessor/s

Reviewer/s

Contributor/s

Justification

History

• 2008
  Least Concern
• 2004
  Least Concern
• 1994
  Not Recognized
• 1988
  Not Recognized

Western screech-owls are closely linked to the riparian habitats of its range; these areas are often the first habitat in any given area to suffer the effects of urban development. Although pairs nesting in suburban areas are generally tolerant of humans close to their nests, they may be sensitive to local disturbance at nest sites from frequent visits by birders (Hardy et al., 1999; Cannings and Angell, 2001). Breeding populations are continually threatend by rapid urbanization and degradation of habitat, and face possible competition from exotic species such as European starlings (Sturnus vulgaris) (Hardy et al., 1999).

Currently there are no official data on the trends of population densities for western screech-owls. However, their populations are probably declining slowly as habitat is lost (Cannings and Angell, 2001).

Western screech-owls are protected by the US MBTA and are listed under Appendix II by CITES, but are not listed on the US Federal List or the IUCN Red List.

US Migratory Bird Act: protected

US Federal List: no special status

CITES: appendix ii

IUCN Red List of Threatened Species: least concern

Canada

Rounded National Status Rank: N4 - Apparently Secure

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Reasons: Still widespread; population probably stable in many areas, probably declining in others. Threatened by habitat loss and/or degradation, particularly the loss of riparian forests and woodlands.

Global Short Term Trend: Relatively stable to decline of 30%

Comments: No rangewide data, but probably declining slowly as habitat declines (Cannings and Angell 2001). Definite declines have been noted in the more developed parts of southwestern British Columbia (Chaundy-Smart 2002).

Degree of Threat: High

Comments: Primary threat is loss or degradation of habitat. Closely linked to riparian forests and woodlands over much of its range, and this is often the first habitat in any given area to be altered, especially in the dry southwest (Cannings and Angell 2001). On coastal British Columbia, may be threatened by largescale logging (Chaundy-Smart 2002). In the Pacific Northwest, traditional territories have been abandoned coincident with the arrival of Barred Owls in an area (Cannings and Angell 2001).

Global Protection: Very many (>40) occurrences appropriately protected and managed

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

Western screech-owls can live in suburban habitats where nest and root sites are available. Pairs nesting in these suburban habitats are often tolerant of humans close to their nests , this allows birders to visit their nest sites (Cannings and Angell, 2001). In addition, Otus kennicottii (previously thought to be conspecific with Otus asio), challenges researchers to discover more about this magnificent bird and hopefully urge conservationists to adopt an active role in habitat preservation.

Positive Impacts: ecotourism ; research and education