Species: Otus flammeolus

Flammulated Owl
Species

    Articles:

    Flammulated Owl (Otus flammeolus)

    This article was originally published by the Washington Department of Fish and Wildlife as part of its annual report Threatened and Endangered Wildlife in Washington.

    Flammulated owl (photo from Greg Lasley, USGS).
    Kingdom
    Animalia
    Phylum
    Craniata
    Class

    Aves

    Order

    Strigiformes

    Family

    Strigidae

    Genus

    Otus

    Classification
    Other Global Common Names
    Petit-duc nain - Tecolote Ojo Oscuro
    Informal Taxonomy
    Animals, Vertebrates - Birds - Other Birds
    Formal Taxonomy
    Animalia - Craniata - Aves - Strigiformes - Strigidae - Otus - O. SCOPS and O. FLAMMEOLUS have been considered conspecific by some authors (Terres 1980).
    Short General Description
    A small dark-eyed owl with small ear tufts.
    Migration
    false - false - true - DNA data indicate very low differentiation among populations in different mountain ranges in New Mexico and Utah; evidently the species exhibits long-distance natal dispersal and frequent intermountain dispersal (Arsenault et al. 2005).
    Non-migrant
    false
    Locally Migrant
    false
    Food Comments
    Mainly hunts at night and eats nocturnal arthropods (McCallum 1994a and 1994b). Marshall (1957, cited in USDA Forest Service 1994) reported that most hunting activity occurs at dawn and dusk; McCallum (1994a, 1994b) reported that species hunts exclusively at night. Feeds on various insects (e.g., moths, beetles, grasshoppers, crickets, caterpillars; McCallum 1994a, 1994b). Moths (esp. NOCTUIDAE and GEOMETRIDAE) and beetles are especially important (Reynolds and Linkhart 1987b; Marshall 1957, cited in USDA Forest Service 1994). Possibly responds to spruce budworm outbreaks (see McCallum 1994b). May occasionally eat small mammals or birds (Bull 1978; Holt 1996), but frequency is debated (McCallum 1996). See McCallum (1994a, 1994b) for detailed information on diet composition. <br><br>Foraging tactics include hawk-gleaning, hawking, hover-gleaning, and drop-pouncing; will also glean insects from trunks and branches (Reynolds and Linkhart 1987; Zeiner et al. 1990, cited in USDA Forest Service 1994). Most foraging in Oregon and New Mexico occurred along the interface between forest or woodland and grassland (see McCallum et al. 1995). In New Mexico, sit-and-wait foraging occurred 3-50 meters from nests (McCallum et al. 1995).
    Reproduction Comments
    Has low reproductive rate (McCallum 1994b). Clutch size is two to four (usually two to three); incubation lasts 21-26 nights, by female (male brings food); nestling period reported as 22-24 nights and 21-23 days; fledglings are tended by both parents (divide brood, Colorado), independent about 1 month after fledging. See Johnsgard (1988) for review of egg dates. Fledging occurs in July-August. Brood size most often is two. Maximum recorded longevity in the wild is about 7-8 years (Reynolds and Linkhart 1990). In California, breeds May through October with peak activity in June and July (Zeiner et al. 1990, cited in USDA Forest Service 1994). Rates of nest success and productivity generally unknown. In New Mexico, adults were site-faithful and tended to maintain pair-bonds between years; juveniles showed little natal philopatry (Arsenault et al. 2005).
    Ecology Comments
    Individuals occupy same breeding territory in successive years (Reynolds and Linkhart 1987a). Territory size about 5.2 square kilometers; males show strong territory fidelity but females may disperse to adjacent territories (dispersal distance averaged 474 meters; Reynolds and Linkhart 1987a). Territory size usually remains same from year to year, even if adjacent territories unoccupied (McCallum 1994a). Territorial boundaries often occur along ridgetops (Reynolds 1987). <br><br>Singing owls move widely within home range. Male foraging, territorial defense, resting and day-roosting were confined to the home range in a Colorado study; home range size appeared to be influenced by canopy volume and range shape by topography (Linkhart 1984, cited in McCallum 1994b). Nesting home ranges vary from 5.5 to 24.0 hectares, and may diminish in size during the breeding season (McCallum 1994b). In Colorado averaged 14 hectares; foraging activity concentrated in 1-4 areas within home range (Reynolds and Linkhart 1987a). Both sexes make extra-range movements during the breeding season (Reynolds and Linkhart 1990). <br><br>Generally fewer than 4 singing males per 40 hectares in Oregon, British Columbia, and Colorado. Density of 5.3 males per square kilometer reported from California (Johnsgard 1988). Densities of singing males in Idaho averaged 0.41 per 40 hectares (Atkinson and Atkinson 1990); and in Oregon from 0.28 to 0.52 males per 40 hectares (Groves et al. 1997). Nests per 100 hectares averaged 2.9 in New Mexico, 2.1 in Colorado, and 1.4 in Oregon (not significantly different; see McCallum et al. 1995). In New Mexico, nest sites averaged 260 meters from the nearest neighbor (McCallum et al. 1995). Territories remain same size in successive years and rarely expand when a neighbor is absent (Reynolds and Linkhart 1990). <br><br>PREDATORS: Recorded predators include accipiters and Great Horned Owl (BUBO VIRGINIANUS). Nest predation documented by Northern Flying Squirrel (GLAUCOMYS SABRINUS; McCallum 1994b). <br><br>COMPETITORS: Squirrels and other avian cavity nesters compete for nest cavities, and as Flammulated Owl comes late to breeding grounds, competitors may limit nest site availability. Bats may compete for nocturnal insect prey (McCallum 1994b).
    Length
    17
    Weight
    57
    NatureServe Global Status Rank
    G4
    Global Status Last Reviewed
    2000-11-16
    Global Status Last Changed
    2000-11-16
    Conservation Status Map
    <img src="http://www.natureserve.org/explorer/servlet/GetMapGif?CA.BC=S3&US.AZ=S4&US.CA=S3&US.CO=S4&US.ID=S3&US.MT=S3&US.NN=S4&US.NV=S4&US.NM=S3&US.OR=S3&US.SD=S1&US.TX=S3&US.UT=S3&US.WA=S3&US.WY=S1" alt="Conservation Status Map" style="width: 475px; height: auto;" />
    Global Range
    FG - 20,000-2,500,000 square km (about 8000-1,000,000 square miles) - FG - BREEDING: locally from southern British Columbia, western Montana, and northern Colorado south to southern California, southern Arizona, southern New Mexico, western Texas, southeastern Coahuila, Nuevo Leon (AOU 1983) (to 3700 m, Contreras-Balderas 1992), and central Mexico (Sibley and Monroe 1990, McCallum 1994a). NON-BREEDING: central Mexico south in highlands to Guatemala and El Salvador, casually north to southern California (AOU 1983).
    Global Range Code
    FG
    Global Range Description
    20,000-2,500,000 square km (about 8000-1,000,000 square miles)
    ELEMENT_GLOBAL.2.104998