Psiloscops flammeolus

BREEDING: Montane forest, usually open conifer forests containing pine, with some brush or saplings (typical of the physiognomy of pre-European settlement ponderosa pine forests). Shows a strong preference for "yellow pine," i.e. ponderosa pine (PINUS PONDEROSA) and Jeffrey pine (P. JEFFREYI), throughout its range (McCallum 1994b). Prefers mature growth with open canopy; avoids dense young stands. Found in cooler, semi-arid climate, with high abundance of nocturnal arthropod prey and some dense foliage for roosting (McCallum 1994a). Absent from warm and humid pine forests and mesic ponderosa pine/Douglas-fir (McCallum 1994a, Wright et al. 1997). Most often found on ridges and upper slopes (Bull et al. 1990, Groves et al. 1997).

In British Columbia, uses dry interior Douglas-fir (PSEUDOTSUGA MENZIESII) where ponderosa pine may be a codominant, but pure ponderosa pine is avoided. Also sometimes in pure aspen and, locally, in spruce (PICEA sp.)/Douglas-fir and lodgepole pine (PINUS CONTORTA)/Douglas-fir. Prefers forests dominated by trees more than 100 years old. Highest densities found in 140 year-old to more than 200 year-old forests; owls were restricted to forests with multi-layered canopies with an abundance of large, well-spaced trees interspersed with grassy openings up to 2 hectares in size, and where cavity-bearing snags were "moderately common" (Howie and Ritcey 1987, van Woudenberg 1999). A study in the Kamloops area that tested a habitat model in Douglas-fir/ponderosa pine found three variables to be significant predictors for occupied habitat: elevation (between 850 and 1,150 meters), age class (older stands), and canopy closure (40 to 50 percent; Christie and van Woudenberg 1997).

In California, breeds in conifer habitats from ponderosa pine up to red fir (ABIES MAGNIFICA) forests (Verner and Boss 1980. In Idaho, found mostly in stands of ponderosa pine, Douglas-fir, or mixtures of the two, occasionally in stands of pure Douglas-fir or aspen where ponderosa pine absent; 65 percent of detections on upper slopes or ridges; tree densities approximately 500 per hectare; mean dbh for all trees 32 centimeters (Groves et al. 1997). In Montana, associated with mature and old-growth xeric ponderosa pine/Douglas-fir stands (Holt and Hillis 1987, Wright et al. 1997); and in landscapes with higher proportions of suitable forest and forest with low to moderate canopy closure (Wright et al. 1997).

In Colorado, shows strong preference for old-growth ponderosa pine and Douglas-fir, using older trees for foraging and singing (Reynolds and Linkhart 1992, Linkhart and Reynolds 1997). Territories consistently occupied by breeding pairs were those containing largest portion (more than 75 percent) of old-growth (200-400 years), whereas territories occupied by unpaired males and rarely by breeding pairs contained 27-68 percent old-growth (Linkhart and Reynolds 1997). Aspen (POPULUS TREMULOIDES) often a component of nesting habitat in Colorado and Nevada (Reynolds and Linkhart 1987b, McCallum 1994b). In northern Utah, successfully nested in nest boxes in montane deciduous forests dominated by aspen with some scattered firs (Marti 1997). Will use pinyon-juniper stands on Colorado Plateau (McCallum 1994b). In southwest, associated mainly with ponderosa or Jeffrey pine, often intermixed with aspen or oaks (QUERCUS).

NEST: Most often nests in an abandoned tree cavity made by Pileated Woodpecker (DRYOCOPUS PILEATUS), flicker (COLAPTES sp.), sapsucker (SPHYRAPICUS sp.) or other large primary cavity nester, at heights from 1 to 16 meters (Reynolds et al. 1989). Uses dead, large-diameter pine, Douglas-fir or aspen tree; occasionally uses natural cavity or nest box. Nearly always nests in open conifer forest with large old trees, scattered thickets of shrubs/saplings, and clearings (McCallum 1994a). Closely associated with large, mature trees for nesting (Bull and Anderson 1978; Reynolds and Linkhart 1984, 1987a, 1987b; McCallum and Gehlbach 1988). In a New Mexico study site, preferred nesting areas that have low shrub density, high canopy height, and high importance of mature pinyon pine (PINUS EDULIS); nest sites had fewer shrubs in front of than behind cavity entrance; vegetation characteristics apparently more limiting than nest-tree characteristics (McCallum and Gehlbach 1988). Nest sites usually were within 50 meters of grassland; most adults did not nest in the same tree cavity in successive years despite previous success (McCallum et al. 1995). In Colorado, territories with contiguous old-growth were occupied 12 consecutive years; territories with less than 75 percent old-growth only occupied by original male (Goggans 1986, cited in McCallum 1994a).

For 33 nests studied in northeastern Oregon by Bull et al. (1990), 91 percent were in dead trees and 70 percent were in ponderosa pine. Of the 33 nests, 67 percent were created by Pileated Woodpeckers, 27 percent by Northern Flickers (COLAPTES AURATUS), and 6 percent by decay. Used Pileated Woodpecker cavities significantly more than expected based on availability. Also: (1) average dbh of nest trees was 72 centimeters and height of nest cavity was 12 meters; (2) owls used large-diameter nest trees large enough at least for Northern Flicker cavities; (3) nests were located on ridges and upper slopes with east or south aspects; and (4) nests were in stands of more than 50 centimeter dbh ponderosa pine mixed with Douglas-fir or Grand fir (ABIES GRANDIS). See Bull et al. (1990) for information on nesting habitat in Oregon.

FORAGING: Prefers yellow pine and/or Douglas-fir for foraging, and these forest types apparently support a particular abundance of favored lepidopteran prey (McCallum 1994b). In Oregon, forage in ponderosa pine and Douglas-fir types with low to medium stem density, but show particularly preference for forest/grassland ecotone (Goggans 1986, cited in McCallum 1994b). In Colorado, preferred to forage in old-growth (more than 200 years), which was related both to an abundance of lepidopteran prey and to the open crowns and park-like spacing of trees which allowed greater room to maneuver for the owls (Reynolds et al. 1989). May focus foraging in a few "intensive foraging areas" within home range, averaging 1 hectare per range (Linkhart 1984, cited in McCallum 1994b).

ROOST: In dense vegetation, thickets, or mistletoe that provide shade and protection from predators; often roosts close to trunks in fir or pine trees, or in cavities (McCallum 1994b, USDA Forest Service 1994). In Oregon, uses mixed coniferous forest rather than pure ponderosa pine (Goggans 1986, cited in McCallum 1994a). In Colorado, uses large Douglas-firs or pines with spreading form (Linkhart 1984, cited in McCallum 1994a). Roosts close to nest (20 - 25 meters) during nestling stage and just before fledging, farther away before and after (McCallum 1994a). In British Columbia, roosted in regenerating thickets of Douglas-fir (Howie and Ritcey 1987).

MIGRATION: In wooded and open areas in lowlands and mountains, including riparian areas and breeding habitat (McCallum 1994a).

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).

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).

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).

PREDATORS: Recorded predators include accipiters and Great Horned Owl (BUBO VIRGINIANUS). Nest predation documented by Northern Flying Squirrel (GLAUCOMYS SABRINUS; McCallum 1994b).

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).

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).