“INTERIOR” WESTERN SCREECH-OWL Otus kennicottii macfarlanei Original prepared by R.J. Cannings

Species Information subspecies with brown base colour to its plumage, while O. kennicottii macfarlanei is greyer in colour and even larger in size.

The Western Screech-Owl was first described in 1867, Distribution but was long considered conspecific with the Eastern Global Screech-Owl, Otus asio (e.g., AOU 1957). One hundred years later, Marshall (1967) recognized four incipient Resident along the Pacific coast from southern species within this larger taxon: O. asio, O. kennicottii, Alaska south to Baja California, and in the interior O. seductus, and O. cooperi. This separation was areas of western North America from southern formalized by AOU (1983) by resurrecting O. British Columbia south through western Montana, kennicottii and giving it the English name Western western Colorado, and western Texas south to Screech-Owl. Indeed, AOU (1983, 1998) and König et central Mexico. The Interior Western Screech-Owl al. (2000) now consider all four of Marshall’s incipient occurs east of the Cascade Mountains from southern species as allospecies of a superspecies. British Columbia, south to Washington, Oregon, Idaho, and Montana. Fifteen subspecies were recognized by Peters (1940) and 13 by AOU (1957). In the next major revision, British Columbia Marshall (1967) considered much of the geographic The Interior Western Screech-Owl occurs in the variation in Western Screech-Owls to be clinal, and Okanagan Valley. There are scattered records further reduced the number of subspecies to eight. elsewhere in the southern Interior but no evidence Hekstra (1982a, 1982b), on the other hand, recog- of breeding. It probably breeds, at least irregularly, in nized 18 subspecies. In a recent revision based the Thompson Valley between Chase and Spences largely on morphometrics, Gehlbach (2003) retains Bridge. Breeding has recently been confirmed in the eight subspecies, only slightly different from West Kootenays near Castlegar and Creston. Marshall’s treatment. Subspecies that range into British Columbia are: Forest region and districts • O. kennicottii kennicottii, along entire coast Southern Interior: Arrow Boundary, Cascades, including the Gulf Islands and Vancouver Island. Kamloops, Kootenay Lake, Okanagan Shuswap • O. kennicottii macfarlanei, southern Interior, and west Kootenays. Ecoprovince and ecosections SIM: EKT, SCM, SFH, SHH, SPM Description SOI: GUU, NIB, NOB, NOH, NTU, OKR, SHB, SOB, SOH, irregular in STU, THB, TRU The Western Screech-Owl is a small owl (150–250 g) with noticeable feather tufts on the corners of its Biogeoclimatic units head. Generally cryptically coloured; breast and BG: xh1, irregular in xh2, xw, xw1 belly are pale with dark streaks, back is brownish PP: dh1, dh2, xh1, xh2 (coast) or brownish-grey (interior) with fine dark streaks. O. kennicottii kennicottii is generally a large

1 Accounts and Measures for Managing Identified Wildlife – Accounts V. 2004 1 2 Accounts and Measures for Managing Identified Wildlife – Accounts V. 2004 IDF: dk1, dk2, dk3, dm1, mw1, mw2, xh1, xh1a, Dispersal and movements irregular in xh2, xw The Western Screech-Owl is non-migratory; young ICH: dw, mw2, irregular in xw disperse in late summer and fall to establish Broad ecosystem units new territories. Both male and female young dis- CR, DF, DP, IG, PP, RR, SP, WL, WR perse from the natal area, but on average females travel about three times as far as males (about 15 km Elevation vs. 5 km) in the first 3 months of dispersal 0–700 m (Ellsworth and Belthoff 1997).

Life History Habitat Diet and foraging behaviour Structural stage 6: mature forest The Western Screech-Owl is a generalist predator on 7: old forest small , including mice, shrews, birds, insects, frogs, salamanders, crayfish, fish, and earthworms Important habitats and habitat features (Cannings and Angell 2001). Nesting Reproduction Breeding territories are closely associated with riparian habitats, particularly those dominated by Western Screech-Owls nest in tree cavities, including black cottonwood (Populus trichocarpa), trembling those excavated by Pileated aspen (Populus tremuloides), and water birch (Betula ( pileatus) and Northern Flickers occidentalis) (Cannings 1997). Since cavities are (Colaptes auratus); they also readily use nest-boxes. needed for both nesting and roosting, a breeding British Columbia nests ranged from 1.2 to 12.2 m territory must contain at least two suitable cavities above ground; all nests reported were in trees to be useful to a pair of screech-owls. Nest trees may >25 cm dbh (n = 43; Campbell et al. 1990). There is be in decay class 2 through 6. a strict division of labour; males provide all the food for females and young while the females incubate Nesting and roosting sites are in tree cavities, usually the eggs and brood the young. Clutch size is two to those made by Northern Flickers or Pileated Wood- seven eggs, usually three to five (Cannings and peckers in large diameter deciduous trees (though Angell 2001). Egg dates in British Columbia range coniferous trees are also used). Dense vegetation and from 17 March to 31 May (n = 49), most (53%) thickets are also used for roosting. Because cavities 9–21 April; dates for young in nests range from of Pileated and are 19 April to 21 August (n = 53), with 51% from most often used, it may be important to consider the 8 May to 3 June (Campbell et al. 1990). nesting requirements of these species in ecosystems where the Interior Western Screech-Owl occurs Site fidelity (see Appendix 12). Pairs are resident throughout the year on nesting In the Okanogan National Forest, Pileated Wood- territories (Cannings and Angell 2001). pecker nesting sites generally had a high live basal Home range area and tree density, and also a large number of snags in all diameter classes (Madsen 1985). Similar Home range sizes can be very small in optimal conclusions about the importance of high densities habitat, but a reasonable estimate for home range of large trees and snags have been found in other size in British Columbia would be about 2.5–10 ha similar western coniferous forests. The Northern (Cannings and Angell 2001). Flicker is less selective in stand structural features, and generally nest trees were located either within or

3 Accounts and Measures for Managing Identified Wildlife – Accounts V. 2004 3 close to open forest areas. However, Northern Flickers and 5 (Madsen 1985). Nest trees in northwestern use old Pileated Woodpecker cavities. Montana often had broken tops and fire scars were present on ≥50% of western larch, ponderosa pine, Pileated Woodpeckers in northwestern Montana and aspen nest trees (McClelland and McClelland selected mainly western larch and occasionally 1999). In northern Oregon, 45% of Pileated Douglas-fir as nest trees (McClelland and Woodpecker nest trees had intact tops, whereas 49% McClelland 1999). They used ponderosa pine where had ≥10% of the top broken off (these were largely there were groves almost entirely composed of ponderosa pine) (Bull 1987). Alternately, 92% of the ponderosa pine and Douglas-fir. In riparian forests, nest trees in Alberta (mainly aspen) were living but nest trees were in large black cottonwood and all all had signs of heartwood decay and conks were aspen nest trees were in monospecific groves of present on 62% of nest trees (Bonar 1997). aspen (McClelland and McClelland 1999). In northern Montana and in the aspen parklands in Alberta, aspen often is the only tree species that Conservation and reaches sufficient size for Pileated Woodpecker nesting (Bonar 1997; McClelland and McClelland Management 1999). In south-central British Columbia, Pileated Status Woodpeckers nested exclusively in trembling aspen (Harestad and Keisker 1989). In the Okanogan The Interior Western Screech-Owl is on the National Forest, Northern Flickers selected provincial Red List in British Columbia. It is ponderosa pine and western larch in greater propor- considered Endangered in Canada (COSEWIC 2002). tion than Douglas-fir or other species (Madsen 1985). Northern Flickers preferred trembling aspen Summary of ABI status in BC and adjacent to conifers near Riske Creek (Wiebe 2001). Diameter jurisdictions (NatureServe Explorer 2002) at breast height (dbh) of nest trees differed particu- larly between coniferous and deciduous trees for BC ID MT OR WA Canada Global both species of cavity-nester (Table 1). S1 S4 S3S4 S4? S5 N1 G5T4 In the Okanogan National Forest, Pileated Wood- pecker nest trees were exclusively in decay stages 4

Table 1. Dbh (mean ± SD) (cm) of Pileated Woodpecker and Northern Flicker nest trees in several locations.

Pileated Northern Forest Location n Woodpecker n Flicker Citation

Coniferous Blue Mountains Oregon 13 75.3 ± 11.7 Bull 1975 Coniferous Okanogan National Forest 6 84.2 ± 17.5 16 70.4 ± 27.2 Madsen 1985 Coniferous Northern Montana 89 73.4 ± 1.9 McClelland and McClelland 1999 Coniferous South central 20 40.5 ± 7.1 17 31.9 ± 9.9 Harestad and British Columbia Keisker 1989 Deciduous trees Riske Creek, 159 33.87 ± 10.34 Wiebe 2001 British Columbia

4 Accounts and Measures for Managing Identified Wildlife – Accounts V. 2004 Trends Legal Protection and Habitat Conservation Population trends Population trends are unknown, but is likely slowly The Western Screech-Owl, its nests, and its eggs are declining, as habitat is lost at lower elevations in the protected from direct persecution by the provincial Okanagan Valley. Wildlife Act. Habitat trends Some habitat is protected in the following parks: Coldstream Regional Park, Inkaneep Provincial About half the riparian habitat in the south Park, Okanagan Mountain Provincial Park, Okanagan Valley has been lost to urban or agricul- South Okanagan Grasslands Provincial Park, tural development over the last 50 years (Cannings White Lake Grasslands Provincial Park, Woodhaven et al. 1999) and a similar loss has likely occurred in Regional Park, Mission Creek, Duck Lake, and Lac the north Okanagan. This loss is particularly severe du Bois parks. in the main valley and less critical along small creeks. Habitat conservation may be partially addressed by Threats the old forest retention targets (old growth manage- ment areas), riparian reserves, and wildlife tree Population threats retention area recommendations in the results Coastal populations of Western Screech-Owls seem based code. to have suffered significant declines in the last The results based code riparian guidelines likely 10 years due to a newly established predator, the afford little direct protection for Interior Western (Strix varia) (pers. obs.; J. Hobbs, pers. Screech-Owl habitat, since many territories are along comm.). Barred Owls began nesting on the south very small non fish bearing streams and wetlands. coast in the early 1990s and anecdotal evidence Harvesting is permitted within the riparian manage- points to a concomitant decline in Western Screech- ment zones often resulting in loss of large diameter Owl breeding populations since then, both in the trees and snags for nesting and roosting. It is also Greater Vancouver and Victoria areas (pers. obs.; likely that upland forest habitat is also important for D. Fraser, pers. comm.). Barred Owls are foraging. potentially a threat in the Interior as well (M. Chutter, pers. comm.) Special riparian management zones outlined in the Okanagan Shuswap Land and Resource Management Habitat threats Plan are similar to those of the results based code. Habitat loss is the primary threat to the Interior Identified Wildlife Provisions Western Screech-Owl which occurs in riparian woodlands at low elevations in the Okanagan Valley, Sustainable resource management and where approximately half of the suitable habitat has planning recommendations been lost in the last 50 years and most of the Because this species depends largely on woodpecker remaining habitat is degraded to some extent cavities, particularly those of Northern Flickers and (Cannings et al. 1999). Livestock grazing, and Pileated Woodpeckers, for nest sites, management burning to clear shrubs has reduced or altered practices that benefit woodpeckers will also enhance suitable habitats along the Nicola Valley (J. Hobbs, habitat for the Western Screech-Owl. pers. comm.) ™ The objective for this species is to maintain wildlife trees and green recruitment trees for nesting across the breeding range and over time. Consider wildlife tree retention (WTR) areas, RMAs, and OGMA objectives for this species in

5 Accounts and Measures for Managing Identified Wildlife – Accounts V. 2004 5 the following forest districts: Okanagan Shuswap, Design Kamloops, Cascades, and Arrow Boundary. Design the WHA to minimize disturbance and ™ Blocks should be assessed to identify potentially maintain suitable foraging habitat. The WHA suitable WTR areas. Suitable WTR areas for this species should be based on the information in should include a 5–12 ha core area for the nest area Table 2. and may include a ~100 m management zone ™ It is recommended that salvage not occur in (i.e., smaller WHAs may be managed as a no harvest WTR areas and OGMAs established to provide core area only). The management zone should habitat for this species. In addition, these areas include suitable foraging habitat. Other features to should be designed to include as many suitable include are large diameter snags (particularly black wildlife trees as possible and that they should be cottonwood, trembling aspen, water birch, and maintained over the long term (>80 years). broadleaf maple) with suitable nest cavities. ™ Maintain forested riparian management zones. General wildlife measures Wildlife habitat area Goals Goal 1. Maintain nesting and foraging habitat. Because few nest areas are known for this subspecies, 2. Maintain an adequate supply of suitable wildlife these sites should be established as WHAs. Suitable trees and associated nest and roost cavities. habitat should be managed through the wildlife tree 3. Maintain a healthy riparian habitat. retention within landscape level planning objectives. 4. Minimize disturbance to roost and nest sites. 5. Maintain native vegetation. Feature 6. Maintain/encourage deciduous component in Establish WHAs at known nest sites or occupied riparian and conifer stands. residences. Residency is indicated by detections 7. Ensure WHA is windfirm. during the breeding season. 8. Maintain riparian areas in properly functioning condition. Size Typically between 5 and 30 ha. Size should be based Measures on estimated home range size using habitat suit- Access ability and number of occupied breeding territories. • Do not construct roads or stream crossings in the Areas of highly suitable habitat may have more than core area. Within the management zone, avoid one occupied breeding territory. constructing roads or stream crossings.

Table 2. Preferred WTP characteristics for the Interior Western Screech-Owl

Attribute Characteristics

Size (ha) ≥2.5 ha Location PPxh, PPdh, IDFxh, IDFxw, IDFdk, IDFmw; riparian areas Tree features visible woodpecker or natural cavities Tree species deciduous preferred; trembling aspen, black cottonwood, water birch, Douglas-fir, possibly ponderosa pine, and western larch Tree size (dbh) deciduous spp.: 34–44 cm or larger; coniferous spp. 74–85 cm or larger; in the absence of trees with the preferred dbh, trees with ≥30 cm dbh should be retained for recruitment Wildlife tree class 2–6

6 Accounts and Measures for Managing Identified Wildlife – Accounts V. 2004 Harvesting and silviculture Cross References • Do not harvest or salvage within the core area. Lewis’s Woodpecker, Yellow-breasted Chat • In PP and IDF zones, selective harvest of ≤20% basal area may occur within the management References Cited zone provided no suitable wildlife trees (see Table 2) are removed. American Ornithologists’ Union (AOU). 1957. Check- • Do not harvest or salvage within the manage- list of North American birds. 5th ed. Am. Ornithol. ment zone during the breeding season (1 March Union, Wash., D.C. to 15 August). _____. 1983. Check-list of North American birds, 6th ed. Am. Ornithol. Union, Wash., D.C. • Retain deciduous species. _____. 1998. Check-list of North American birds, 7th • Within riparian management zones, retain >60% ed. Am. Ornithol. Union, Wash., D.C. of trees including all suitable wildlife trees (see Table 2). Bonar, R.L. 1997. Pileated Woodpecker habitat ecology in boreal forests: 1996–1997 progress report. Pesticides Weldwood of Canada Ltd., Hinton, Alta. 43 p. • Do not use pesticides. Bull, E.L. 1975. Habitat utilization of the Pileated Woodpecker, Blue Mountains, Oregon. M.Sc. thesis. Range (BG, PP, and IDF zones) Oreg. State Univ., Corvallis, Oreg. 58 p. • Plan livestock grazing (timing, distribution, and _____. 1987. Ecology of the Pileated Woodpecker in level of use) to maintain desired structure of north-eastern Oregon. J. Wildl. Manage. plant community, desired stubble height, and 51:472–481. browse utilization. Campbell, R.W., N.K. Dawe, I. McTaggart-Cowan, J.M. • Do not place livestock attractants within WHA. Cooper, G.W. Kaiser, and M.C.E. McNall. 1990. The birds of British Columbia. Vol. II: Nonpasserines. • Do not burn understorey vegetation. Diurnal birds of prey through woodpeckers. Royal B.C. Mus., Victoria, B.C., and Can. Wildl. Serv., Recreation Delta, B.C. 636 p. • Do not construct trails within 50 m of a known Cannings, R.J. 1997. A survey of the Western Screech- nest site. Owl (Otus kennicottii macfarlanei) in the interior of British Columbia. B.C. Min. Environ., Lands and Additional Management Parks, Victoria, B.C. Unpubl. rep. Considerations Cannings, R.J. and T. Angell. 2001. Western Screech- Owl. In Birds of North America, No. 597. A. Poole Consider fencing stream or stock-watering works and F. Gill (editor). Birds of North America, Inc., to limit the access of livestock to a stream within Philadelphia, Penn. the WHAs. Cannings, R.J., E. Durance, and L. Scott. 1999. South Okanagan Ecosystem Recovery Plan: scientific Consider using nest-boxes if wildlife trees and other assessment. B.C. Environ., Penticton, B.C. trees with suitable cavities have been felled for safety Unpubl. rep. reasons. Committee on the Status of Endangered Wildlife in Canada (COSEWIC). 2002. Canadian Species at Information Needs Risk. www.speciesatrisk.gc.ca 1. Habitat use and home range size. It would be Ellsworth, E. and J.R. Belthoff. 1997. Sex-biased very useful to find out the degree to which owls dispersal of young Western Screech-Owls (Otus use coniferous forests adjacent the riparian zone kennicottii) in southwestern Idaho. In Biology and during foraging bouts. conservation of owls of the Northern Hemisphere: 2nd Int. Symp. J.R. Duncan, D.H. Johnson, and T.H. 2. Impact of Barred Owl predation and any Nicholls (editors). Feb. 5–9, 1997, Winnipeg, Man. opportunity to design WHAs to reduce/ U.S. Dep. Agic. For. Serv., North Cent. Res. Stn., minimize predation by Barred Owls. Gen. Tech. Rep. 190, pp. 155–159.

7 Accounts and Measures for Managing Identified Wildlife – Accounts V. 2004 7 Gehlbach, F.R. 2003. Body size variation and McClelland, B.R. and P.T. McClelland. 1999. Pileated evolutionary ecology of eastern and western Woodpecker nest and roost trees in Montana: links screech-owls. Southwest. Nat. with old-growth and forest “health.” Wildl. Soc. Harestad, A.S. and D.G. Keisker. 1989. Nest tree use by Bull. 27:846–857. primary cavity-nesting birds in south central NatureServe Explorer. 2002. An online encyclopaedia British Columbia. Can. J. Zool. 67:1067–1073. of life. Version 1.6. NatureServe. Arlington, VA. Hekstra, G.P. 1982a. A revision of the American Available at http://www.natureserve.org/explorer/ screech-owls (Otus: Strigidae). Ph.D. thesis. Vrije Peters, J.L. 1940. Check-list of the birds of the world, Universiteit te Amsterdam, Amsterdam, Vol. 4. Harvard Univ. Press, Cambridge, Mass. Netherlands. Wiebe, K.L. 2001. Microclimate of tree cavity nests: is it _____. 1982b. Description of twenty-four new important for reproductive success in Northern subspecies of American owls (Aves: Strigidae). Bull. Flickers? Auk 118(2):412–421. Zool. Mus. Universiteit Amsterdam 9:49–63. König, C., F. Wieck, and J.-H. Becking. 2000. Owls: a Personal Communications guide to the owls of the world. Yale Univ. Press, New Chutter, M. 2001. Min. Water, Land and Air Protection, Haven, Conn. 462 p. Victoria, B.C. Madsen, S.J. 1985. Habitat use by cavity-nesting birds Fraser, D. 2001. Min. Water, Land and Air Protection, in the Okanogan National Forest, Washington. Victoria, B.C. M.Sc. thesis. Univ. Wash., Seattle, Wash. 113 p. Hobbs, J. 2001. Min. Water, Land and Air Protection, Marshall, J.T. 1967. Parallel variation in North and Victoria, B.C. Middle American screech-owls. West. Found. Vertebr. Zool. Monogr. 1:1–72.

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