Asio otus - (Linnaeus, 1758)
Long-eared Owl
Other English Common Names: long-eared owl
Taxonomic Status: Accepted
Related ITIS Name(s): Asio otus (Linnaeus, 1758) (TSN 177932)
French Common Names: hibou moyen-duc
Spanish Common Names: Buho Cara Café
Unique Identifier: ELEMENT_GLOBAL.2.101120
Element Code: ABNSB13010
Informal Taxonomy: Animals, Vertebrates - Birds - Other Birds
 
Kingdom Phylum Class Order Family Genus
Animalia Craniata Aves Strigiformes Strigidae Asio
Genus Size: B - Very small genus (2-5 species)
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Concept Reference
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Concept Reference: American Ornithologists' Union (AOU). 1998. Check-list of North American birds. Seventh edition. American Ornithologists' Union, Washington, D.C. [as modified by subsequent supplements and corrections published in The Auk]. Also available online: http://www.aou.org/.
Concept Reference Code: B98AOU01NAUS
Name Used in Concept Reference: Asio otus
Taxonomic Comments: The genetic distance (based on allozyme data) between A. otus and A. flammeus is unusually large for congeneric bird species (Randi et al., 1991); further study of their phylogenetic relationships is warranted.
Conservation Status
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NatureServe Status

Global Status: G5
Global Status Last Reviewed: 06Apr2016
Global Status Last Changed: 27Nov1996
Ranking Methodology Used: Ranked by inspection
Rounded Global Status: G5 - Secure
Reasons: Secure due primarily to extensive range; population trends are poorly known.
Nation: United States
National Status: N5B,N5N (05Jan1997)
Nation: Canada
National Status: N5B,N5N,N5M (08Jan2018)

U.S. & Canada State/Province Status
Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
United States Arizona (S2B,S3S4N), Arkansas (S3N), California (S3?), Colorado (S3S4B), Connecticut (S1B), Delaware (S1B,S1N), District of Columbia (SH), Georgia (S4), Idaho (S5), Illinois (S1B,S2N), Indiana (S2), Iowa (S2B,S3N), Kansas (S2B,S3N), Kentucky (S1B,S1S2N), Maine (S1S3B), Maryland (SHB,S1N), Massachusetts (S1B,S2N), Michigan (S1), Minnesota (SNRB), Missouri (SU), Montana (S5), Navajo Nation (S3B,S4N), Nebraska (S4), Nevada (S4), New Hampshire (SU), New Jersey (S2B,S2N), New Mexico (S4B,S4N), New York (S2S3B,SNRN), North Carolina (SUB), North Dakota (SU), Ohio (S1S2), Oklahoma (S1), Oregon (S4?), Pennsylvania (S2B,S2S3N), Rhode Island (SHB,S1N), South Carolina (SNA), South Dakota (S3B,S3N), Tennessee (S2N), Texas (S2B,S3N), Utah (S3S4), Vermont (S1B), Virginia (S1B,S2N), Washington (S3B,S4N), West Virginia (S1B,S1N), Wisconsin (S2B), Wyoming (S4)
Canada Alberta (S4B), British Columbia (S4), Manitoba (S4B), New Brunswick (S2S3), Northwest Territories (SUB), Nova Scotia (S2S3), Ontario (S4), Prince Edward Island (S1?), Quebec (S4), Saskatchewan (S5B,S2N)

Other Statuses

IUCN Red List Category: LC - Least concern
Convention on International Trade in Endangered Species Protection Status (CITES): Appendix II

NatureServe Global Conservation Status Factors

Range Extent: 20,000-2,500,000 square km (about 8000-1,000,000 square miles)
Range Extent Comments: BREEDS: southern and eastern British Columbia to northern Saskatchewan and Prince Edward Island, south to northwestern Baja California, southern New Mexico, northern Mexico, Arkansas, and Virginia. WINTERS: southern Canada to northern Baja California, central Mexico, and Gulf Coast. Also in Old World.

Number of Occurrences: 81 to >300

Population Size: 10,000 to >1,000,000 individuals
Population Size Comments: Guesstimated number of breeding pairs in Canada in the early 1990s was 10,000-20,000 (Kirk et al. 1995).

Short-term Trend Comments: Trends are difficult to ascertain. Reported as "?stable; little data available" in Canada (Kirk et al. 1995).

Other NatureServe Conservation Status Information

Distribution
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Global Range: (20,000-2,500,000 square km (about 8000-1,000,000 square miles)) BREEDS: southern and eastern British Columbia to northern Saskatchewan and Prince Edward Island, south to northwestern Baja California, southern New Mexico, northern Mexico, Arkansas, and Virginia. WINTERS: southern Canada to northern Baja California, central Mexico, and Gulf Coast. Also in Old World.

U.S. States and Canadian Provinces

Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
Color legend for Distribution Map
NOTE: The maps for birds represent the breeding status by state and province. In some jurisdictions, the subnational statuses for common species have not been assessed and the status is shown as not-assessed (SNR). In some jurisdictions, the subnational status refers to the status as a non-breeder; these errors will be corrected in future versions of these maps. A species is not shown in a jurisdiction if it is not known to breed in the jurisdiction or if it occurs only accidentally or casually in the jurisdiction. Thus, the species may occur in a jurisdiction as a seasonal non-breeding resident or as a migratory transient but this will not be indicated on these maps. See other maps on this web site that depict the Western Hemisphere ranges of these species at all seasons of the year.
Endemism: occurs (regularly, as a native taxon) in multiple nations

U.S. & Canada State/Province Distribution
United States AR, AZ, CA, CO, CT, DC, DE, GA, IA, ID, IL, IN, KS, KY, MA, MD, ME, MI, MN, MO, MT, NC, ND, NE, NH, NJ, NM, NN, NV, NY, OH, OK, OR, PA, RI, SC, SD, TN, TX, UT, VA, VT, WA, WI, WV, WY
Canada AB, BC, MB, NB, NS, NT, ON, PE, QC, SK

Range Map
Note: Range depicted for New World only. The scale of the maps may cause narrow coastal ranges or ranges on small islands not to appear. Not all vagrant or small disjunct occurrences are depicted. For migratory birds, some individuals occur outside of the passage migrant range depicted. For information on how to obtain shapefiles of species ranges see our Species Mapping pages at www.natureserve.org/conservation-tools/data-maps-tools.

Range Map Compilers: NatureServe, 2002; WILDSPACETM 2002


U.S. Distribution by County Help
State County Name (FIPS Code)
AZ Apache (04001), Coconino (04005), Graham (04009), La Paz (04012), Maricopa (04013), Mohave (04015), Navajo (04017), Pima (04019), Yavapai (04025)
CA El Dorado (06017), Fresno (06019), Inyo (06027), Kern (06029), Lassen (06035), Modoc (06049)*, Mono (06051)*, Nevada (06057), Orange (06059)*, Riverside (06065)*, San Benito (06069), San Bernardino (06071)*, San Diego (06073), San Luis Obispo (06079), San Mateo (06081), Santa Clara (06085), Yuba (06115)
CT Fairfield (09001), Hartford (09003)*, Litchfield (09005), New Haven (09009), Windham (09015)*
IA Allamakee (19005), Boone (19015), Cass (19029), Clarke (19039), Emmet (19063)*, Lee (19111), Lucas (19117), Marion (19125), Page (19145), Plymouth (19149), Webster (19187), Winneshiek (19191)
IN Fountain (18045), Harrison (18061), Newton (18111), Porter (18127)*, Tippecanoe (18157)*, Warren (18171)
KS Jefferson (20087), Labette (20099), Morton (20129), Nemaha (20131), Phillips (20147), Scott (20171), Stafford (20185)
KY Muhlenberg (21177)
MA Barnstable (25001)*, Dukes (25007)*, Essex (25009)*, Nantucket (25019), Plymouth (25023)*, Worcester (25027)
MI Bay (26017)*, Mackinac (26097), Macomb (26099)*, Oakland (26125)*
MO Livingston (29117)
ND Burke (38013), Burleigh (38015)*, Morton (38059)*, Stutsman (38093)
NJ Atlantic (34001), Bergen (34003), Camden (34007), Cape May (34009), Essex (34013), Hunterdon (34019), Mercer (34021), Middlesex (34023), Morris (34027), Somerset (34035), Sussex (34037), Warren (34041)
NM Mckinley (35031), San Juan (35045)
NV Elko (32007), Esmeralda (32009), Eureka (32011), Nye (32023)
OK Texas (40139)*
PA Beaver (42007), Berks (42011)*, Bradford (42015), Chester (42029)*, Cumberland (42041), Delaware (42045)*, Indiana (42063), Lancaster (42071), Northumberland (42097)
RI Bristol (44001)*, Providence (44007)*
SD Bennett (46007)*, Brookings (46011)*, Custer (46033), Dewey (46041), Hand (46059), Harding (46063), Hughes (46065), Jerauld (46073)*, Marshall (46091)*, Meade (46093)*, Pennington (46103)*, Perkins (46105), Roberts (46109)*, Sanborn (46111)*, Shannon (46113), Stanley (46117), Ziebach (46137)
VT Addison (50001)*, Chittenden (50007), Orleans (50019), Rutland (50021)
WI Ashland (55003), Bayfield (55007), Burnett (55013), Dane (55025), Forest (55041), Marquette (55077), Oneida (55085), Vilas (55125)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
01 Miller (01080202)+, Lower Connecticut (01080205)+*, Charles (01090001)+*, Cape Cod (01090002)+, Narragansett (01090004)+*, Shetucket (01100002)+*, Quinnipiac (01100004)+*, Housatonic (01100005)+, Saugatuck (01100006)+
02 Rondout (02020007)+, Hackensack-Passaic (02030103)+, Raritan (02030105)+, Middle Delaware-Musconetcong (02040105)+, Lower Delaware (02040202)+, Schuylkill (02040203)+*, Brandywine-Christina (02040205)+*, Cohansey-Maurice (02040206)+, Great Egg Harbor (02040302)+, Upper Susquehanna-Tunkhannock (02050106)+, Upper West Branch Susquehanna (02050201)+, Lower Susquehanna-Penns (02050301)+, Lower Susquehanna-Swatara (02050305)+, Lower Susquehanna (02050306)+
04 Beartrap-Nemadji (04010301)+, Menominee (04030108)+, Upper Fox (04030201)+, Little Calumet-Galien (04040001)+*, Brevoort-Millecoquins (04060107)+, Kawkawlin-Pine (04080102)+*, Clinton (04090003)+*, Mettawee River (04150401)+, Otter Creek (04150402)+, Lake Champlain (04150408)+, St. Francois River (04150500)+
05 Middle Allegheny-Redbank (05010006)+*, Conemaugh (05010007)+, Upper Ohio (05030101)+, Beaver (05030104)+, Pond (05110006)+, Middle Wabash-Little Vermilion (05120108)+, Blue-Sinking (05140104)+
07 Upper Minnesota (07020001)+*, Lower St. Croix (07030005)+, Coon-Yellow (07060001)+, Upper Iowa (07060002)+, Turkey (07060004)+, Upper Wisconsin (07070001)+, Flint-Henderson (07080104)+, South Skunk (07080105)+, Pecatonica (07090003)+, Upper Des Moines (07100002)+*, Middle Des Moines (07100004)+, Lake Red Rock (07100008)+, Lower Des Moines (07100009)+, Kankakee (07120001)+*, Iroquois (07120002)+
09 Des Lacs (09010002)+
10 Lake Sakakawea (10110101)+, Beaver (10120107)+, Middle Cheyenne-Spring (10120109)+, Middle Cheyenne-Elk (10120111)+*, Lower Cheyenne (10120112)+*, Lower Belle Fourche (10120202)+*, Painted Woods-Square Butte (10130101)+*, Upper Lake Oahe (10130102)+*, Lower Lake Oahe (10130105)+, Lower Heart (10130203)+*, South Fork Grand (10130302)+, Upper Moreau (10130305)+, Lower Moreau (10130306)+, Fort Randall Reservoir (10140101)+, Bad (10140102)+*, Middle White (10140202)+*, Little White (10140203)+*, Upper Niobrara (10150003)+*, Middle Niobrara (10150004)+*, Pipestem (10160002)+, Upper James (10160003)+*, Turtle (10160009)+, Lower James (10160011)+*, Upper Big Sioux (10170202)+*, Lower Big Sioux (10170203)+, East Nishnabotna (10240003)+, West Nodaway (10240009)+, Nodaway (10240010)+, Middle Republican (10250016)+, Ladder (10260004)+, Upper North Fork Solomon (10260011)+, Middle Kansas (10270102)+, Delaware (10270103)+, Lower Grand (10280103)+, Upper Chariton (10280201)+
11 Rattlesnake (11030009)+, Upper Cimarron (11040002)+, Middle Neosho (11070205)+, Upper Beaver (11100101)+*, Middle Beaver (11100102)+*
14 Middle San Juan (14080105)+, Chaco (14080106)+, Chinle (14080204)+
15 Lower Colorado-Marble Canyon (15010001)+, Hualapai Wash (15010007)+, Little Colorado headwaters (15020001)+, Silver (15020005)+, Upper Puerco (15020006)+, Jadito Wash (15020014)+, Big Sandy (15030201)+, San Francisco (15040004)+, Upper Gila-San Carlos Reservoir (15040005)+, Brawley Wash (15050304)+, Lower Gila (15070201)+, Tenmile Wash (15070202)+, Rio De La Concepcion (15080200)+
16 Smoke Creek Desert (16040203)+*, Lake Tahoe (16050101)+, Diamond-Monitor Valleys (16060005)+, Fish Lake-Soda Spring Valleys (16060010)+
17 South Fork Owyhee (17050105)+
18 Upper Bear (18020126)+, Middle Kern-Upper Tehachapi- (18030003)+, Tulare-Buena Vista Lakes (18030012)+, Coyote (18050003)+, San Francisco Coastal South (18050006)+, Estrella (18060004)+, Salinas (18060005)+, Cuyama (18060007)+, San Gabriel (18070106)+*, Santa Ana (18070203)+*, Aliso-San Onofre (18070301)+*, Surprise Valley (18080001)+*, Honey-Eagle Lakes (18080003)+, Crowley Lake (18090102)+*, Owens Lake (18090103)+*, Death Valley-Lower Amargosa (18090203)+*, Indian Wells-Searles Valleys (18090205)+, Antelope-Fremont Valleys (18090206)+, Coyote-Cuddeback Lakes (18090207)+*, Mojave (18090208)+*, Whitewater River (18100201)+*, Carrizo Creek (18100202)+, San Felipe Creek (18100203)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
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Reproduction Comments: Nests mainly mid-March to mid-May in many areas. Clutch size averages 4-5 in North America, highest in north and west. Incubation lasts 25-30 days, normally by female only. Young leave nest at 20-26 days, fly at 30-40 days, independent at about 2 months. Sexually mature in 1 year. High rodent numbers are essential for nesting success.
Ecology Comments: Breeding density generally not more than 1-2 pairs per sq km, often much less. Home ranges in Wyoming riparian habitat varied from 34-106 hectares (mean 51 hectares; Craighead and Craighead 1956). Gregarious in winter.
Non-Migrant: Y
Locally Migrant: Y
Long Distance Migrant: Y
Mobility and Migration Comments: Migratory in most of Canada and north-central U.S. At Cape May Point, New Jersey, 90% of fall migration was completed between mid-October and late November (Duffy and Kerlinger 1992). See also Russell et al. (1991) for an account of fall migration at Cape May Point, New Jersey.
Palustrine Habitat(s): HERBACEOUS WETLAND, Riparian
Terrestrial Habitat(s): Forest - Conifer, Forest - Hardwood, Forest - Mixed, Old field, Shrubland/chaparral, Woodland - Conifer, Woodland - Hardwood, Woodland - Mixed
Habitat Comments: Deciduous and evergreen forests, orchards, wooded parks, farm woodlots, river woods, desert oases. Wooded areas with dense vegetation needed for roosting and nesting, open areas for hunting. Often associated with conifers in eastern North America, also with deciduous woods near water in West.

Nests in tree usually in old nest of crow, squirrel, hawk, magpie, or heron; sometimes in tree cavity; rarely on ground (e.g., Maples et al. 1995, Wilson Bull. 107:563-565). In northeastern Oregon, nested in dwarf-mistletoe brooms in Douglas-fir in extensive conifer (grand fir) forest (Bull et al. 1989). Apparently commonly nests in same site in successive years. In Idaho, 4 males nested 0.5-1.5 km from natal site.

Adult Food Habits: Carnivore
Immature Food Habits: Carnivore
Food Comments: Opportunistic; feeds on available small mammals (usually <50 g) (Marks 1984). Typical primary prey in North America includes MICROTUS, PEROMYSCUS, and PEROGNATHUS; varies with locality (e.g., THOMOMYS in Oregon; Bull et al. 1989). Typically forages in open grassy area, e.g., marsh, old field, but may forage in forest in some areas (e.g., northeastern Oregon, Bull et al. 1989).
Adult Phenology: Crepuscular, Nocturnal
Immature Phenology: Crepuscular, Nocturnal
Phenology Comments: Basically nocturnal, though diurnal foraging may occur at high latitudes or when feeding young.
Length: 38 centimeters
Weight: 279 grams
Economic Attributes Not yet assessed
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Management Summary Not yet assessed
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Population/Occurrence Delineation
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Group Name: Small and Medium Owls

Use Class: Breeding
Subtype(s): Nest site
Minimum Criteria for an Occurrence: Evidence of historical breeding, or current and likely recurring breeding, at a given location, minimally a reliable observation of one or more breeding pairs in appropriate habitat. Be cautious about creating EOs for observations that may represent single breeding events outside the normal breeding distribution.
Separation Barriers: None.
Separation Distance for Unsuitable Habitat: 5 km
Separation Distance for Suitable Habitat: 5 km
Separation Justification: Separation distance is not intended to delineate demographically independent populations or metapopulations (such units would be quite large) but rather serves to circumscribe breeding occurrences that are of practical size for conservation/management use.

Separation distance is larger than three times the diameter of an average home range for these volant species; based the diameter of larger home ranges of males, e.g. those of Northern Pygmy-Owls given below.

Ferruginous Pygmy-Owl: post-fledging families used 9.3 to about 60 hectares until the young dispersed (Proudfoot and Johnson 2000).

Northern Pygmy-Owl: territory in Colorado estimated to be about 75 hectares (Rashid 1999, cited in Holt and Petersen 2000); home ranges of breeding males in Washington 170-230 hectares (A. Giese, pers. comm., cited in Holt and Petersen 2000); home ranges of males in Sweden averaged 231 hectares (Kullberg 1995).

Northern Saw-whet Owl: Two breeding males had home ranges of 142 and 159 hectares (Cannings 1987). Most breeding habitat probably supports a maximum of about 1 pair/square kilometer, often much less (Cannings 1993); singing males can be as close as about 250 meters apart (Swengel 1990).

Elf Owl: home ranges smaller, range 0.2-2.6, mean 1.0 hectares (Gamel 1997).

Flammulated Owl males had mean home ranges of about 14 hectares in Colorado (Linkhart 1984) and about 16 hectares in Oregon (during the incubation period; Goggans 1986). 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).

Whiskered Screech-Owls had home ranges about 1550 meters long, along permanent creek (Gehlbach and Gehlbach 2000).

Burrowing Owl: In Saskatchewan, the average home range was about 1.2 kilometers in diameter (Haug and Oliphant 1990).

Long-eared Owl: In Wyoming, breeding home range in riparian habitat varied from 34-106 hectares and averaged 51 hectares (Craighead and Craighead 1956).

Short-eared Owl: Breeding territories average 64 -74 hectares (Holt 1992, Clark 1975).

Inferred Minimum Extent of Habitat Use (when actual extent is unknown): .6 km
Inferred Minimum Extent Justification: Conservatively based on an average home range of 27 hectares for a Ferruginous Pygmy-Owl family (Proudfoot and Johnson 2000). A breeding male Northern Saw-whet Owl spent most of its active time in a core area of only 27 hectares (Cannings 1987).

Long-eared Owl: May use an IE of 0.8 km, which is the diameter of an average home range (Craighead and Craighead 1956).

Short-eared Owl: May use an IE of 0.9 km, which is based on an average breeding home range of 65 hectares.

Date: 26Feb2005
Author: Cannings, S., and G. Hammerson
Notes: Contains owls in the genera Otus, Glaucidium, Aegolius, Asio and Athene.

Use Class: Nonbreeding
Minimum Criteria for an Occurrence: Evidence of recurring presence of wintering individuals (including historical); and potential recurring presence at a given location. Occurrences should be locations where the species is resident for some time during the appropriate season; it is preferable to have observations documenting presence over at least 20 days annually. Be cautious about creating EOs for observations that may represent single events.
Separation Barriers: None.
Separation Distance for Unsuitable Habitat: 5 km
Separation Distance for Suitable Habitat: 5 km
Separation Justification: Separation distance larger than three times the diameter of an average home range for these volant species; based the diameter of larger home ranges of males, e.g. those of Northern Pygmy-Owls: in Washington 170-230 hectares (A. Giese, pers. comm., cited in Holt and Petersen 2000); in Sweden, averaged 231 hectares (Kullberg 1995).
Whiskered Screech-Owls had home ranges about 1550 meters long, along permanent creek (Gehlbach and Gehlbach 2000).

Inferred Minimum Extent of Habitat Use (when actual extent is unknown): .6 km
Inferred Minimum Extent Justification: Conservatively based on a home range of 27 hectares; for example, a breeding male Northern Saw-whet Owl spent most of its active time in a 27-hectare core area (Cannings 1987).
Date: 16Apr2002
Author: Cannings, S.

Use Class: Roost
Minimum Criteria for an Occurrence: Evidence of recurring, nonbreeding, communal roosting at a given location; reliable observation of multiple individuals roosting in a distinct habitat patch in multiple years. To avoid creating EOs for ephemeral situations, there should be evidence of communal roosting over at least two different (though not necessarily consecutive) nonbreeding seasons.
Separation Barriers: None.
Separation Distance for Unsuitable Habitat: 5 km
Separation Distance for Suitable Habitat: 5 km
Separation Justification: Separation distance is arbitrary. Pertinent biologically based separation criteria do not exist.
Date: 25Oct2012
Author: Hammerson, G.
Population/Occurrence Viability
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U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
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Authors/Contributors
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Element Ecology & Life History Edition Date: 19Apr1996
Element Ecology & Life History Author(s): Hammerson, G.

Zoological data developed by NatureServe and its network of natural heritage programs (see Local Programs) and other contributors and cooperators (see Sources).

References
Help
  • American Ornithologists' Union (AOU). 1983. Check-list of North American Birds, 6th edition. Allen Press, Inc., Lawrence, Kansas. 877 pp.

  • American Ornithologists' Union (AOU). 1998. Check-list of North American birds. Seventh edition. American Ornithologists' Union, Washington, D.C. [as modified by subsequent supplements and corrections published in The Auk]. Also available online: http://www.aou.org/.

  • Andrews, R. R. and R. R. Righter. 1992. Colorado Birds. Denver Museum of Natural History, Denver. 442 pp.

  • Aquin, P. 1999. Évaluation de la situation des groupes taxonomiques des oiseaux du Québec. Ministère de l'Environnement et de la Faune. 13 pages.

  • Armstrong, W.H. 1958. Nesting and food habits of the long- eared owl in Michigan. Michigan State Univ. Biol. Series 1 (2).

  • Audubon Society. 1981-1985. Breeding Bird Atlas of New Hampshire. (unpublished).

  • B83COM01NAUS - Added from 2005 data exchange with Alberta, Canada.

  • Bent, A. C. 1938. Life histories of North American birds of prey. Part 2. U.S. Nat. Mus. Bull. 170. 482 pp., 92 pls.

  • BirdLife International. 2004b. Threatened birds of the world 2004. CD ROM. BirdLife International, Cambridge, UK.

  • Bull, E. L., A. L. Wright, and M. G. Henjum. 1989. Nesting and diet of long-eared owls in conifer forests, Oregon. Condor 91:908-912.

  • Cadman, M. D., P. F. J. Eagles, and F. M. Helleiner. 1987. The Atlas of Breeding Birds of Ontario. University of Waterloo Press, Waterloo, Canada. 617pp.

  • Campbell, R.W., N.K. Dawe, I. McTaggart-Cowan, J.M. Cooper, G.W. Kaiser, and M.C.E. McNall. 1990. The Birds of British Columbia Vol. 2: Nonpasserines: Diurnal Birds of Prey through Woodpeckers. Royal British Columbia Museum, Victoria, BC.

  • Cannings, R.J. 1995. Status of the Long-eared Owl in the South Okanagan, British Columbia. B.C. Minist. Environ., Lands and Parks, Wildl. Branch. 24 pp. Bulletin B-78.

  • Cannings, S. 2001. EO Specifications for Long-eared Owl (Asio otus). NatureServe, Unpublished. 1 pp.

  • Clark, R. J., D. G. Smith, and L. H. Kelso. 1978. Working bibliography of owls of the world. National Wildlife Federation, Sci. & Tech. Ser. No. 1. 336 pp.

  • Colorado Bird Observatory. 1996. DRAFT 1996 Status of Colorado Birds. Submitted to Colorado Division of Wildlife. December 31, 1996. 137 p.

  • Craighead, J. J., and F. C. Craighead, Jr. 1956. Hawks, Owls and Wildlife. The Stackpole Company, Harrisburg, Pennsylvania, and the Wildlife Management Institute, Washington, D.C.

  • DICKINSON, MARY B., ED. 1999. FIELD GUIDE TO THE BIRDS OF NORTH AMERICA, 3RD ED. NATIONAL GEOGRAPHIC SOCIETY, WASHINGTON, D.C. 480 PP.

  • Demarchi, M.W. and M.D. Bently. 2005. Best Management Practices for Raptor Conservation during Urban and Rural Land Development in British Columbia. B.C. Minist. of Environ., Victoria, B.C. MoE BMP Series.

  • Desrosiers A., F. Caron et R. Ouellet. 1995. Liste de la faune vertébrée du Québec. Les publications du Québec. 122

  • Dionne C. 1906. Les oiseaux de la province de Québec. Dussault et Proulx.

  • Dorn, Jane L. and R.D. Dorn. 1990. Wyoming Birds. Mountain West Publishing, Cheyenne.

  • Downes, C. M., and B. T. Collins. 1996. The Canadian Breeding Bird Survey, 1966-1994. Canadian Wildlife Service Progress Note. 24 pp.

  • Duffy, K., and P. Kerlinger. 1992. Autumn owl migration at Cape May Point, New Jersey. Wilson Bull. 104:312-320.

  • Eckert, Allan W. 1978. The Owls of North America. Weather-vane Books, New York. 278 pp.

  • Evers, D. C. 1992. A guide to Michigan's endangered wildlife. Univ. Michigan Press, Ann Arbor. viii + 103 pp.

  • Fisher, A.K. 1893. The hawks and owls of the United States in their relation to agriculture. Washington U.S. Dept. of Agriculture Bull. no. 6. 210 pp.

  • Godfrey, W. E. 1986. The birds of Canada. Revised edition. National Museum of Natural Sciences, Ottawa. 596 pp. + plates.

  • Harrison, C. 1978. A Field Guide to the Nests, Eggs and Nestlings of North American Birds. Collins, Cleveland, Ohio.

  • Harrison, H. H. 1979. A field guide to western birds' nests. Houghton Mifflin Company, Boston. 279 pp.

  • Johnsgard, P. 1988. North American owls: biology and natural history. Smithsonian Inst. Press. 336 pp.

  • Jones, S. 1988. Owling tips for atlasers. Colorado Bird Atlas Newsletter, no. 3, p.4-5.

  • Judd, W.W. 1978. A Long-eared Owl (Asio otus) and its food at Carr's Bridge, St. Thomas Reservoir, Elgin County, Ontario. Ontario Field Biologist 32(2):34-36.

  • Kingery, H. ed. 1988. Colorado Distribution Latilong Study. Colorado Division of Wildlife, Denver, CO. 81pp.

  • Kirk, D. A., D. Hussell, and E. Dunn. 1995. Raptor population status and trends in Canada. Bird Trends (Canadian Wildlife Service) 4:2-9.

  • Klippell, W.E. and P.W. Parmalee. 1982. Prey of a winter- ing long-eared owl in the Nashville Basin, Tennessee. J. Field Ornith. 53(4):418-420.

  • Marks, J. S. 1984. Feeding ecology of breeding long-eared owls in southwestern Idaho. Can. J. Zool. 62:1528-1533.

  • Marks, J.S., D.L. Evans and D.W. Holt. 1994. Long-Eared Owl; The Birds of North America. Vol. 4, No. 133. American Orinithologists' Union. The Academy of Natural Sciences of Philadelphia.

  • McAtee W.L. 1959. Folk - names of candian birds. National Museum of Canada. Folk - names of candian birds. National Museum of Canada. 74 pages.

  • Nelson, D. 1993. Colorado Bird Atlas: Manual on Use of Breeding Codes. Denver Museum of Natural History, Denver. 27 pp.

  • Nicholls, T. H., and M. R. Fuller. 1987. Owl telemetry techniques. Pages 294-301 IN R.W. Nero, R.J. Clark, R.J. Knapton, and R.H. Hamre, editors. Biology and conservation of northern forest owls. USDA Forest Service, Gen. Tech. Rep. RM-142.

  • Nicholson, C.P. 1997. Atlas of the breeding birds of Tennessee. The University of Tennessee Press. 426 pp.

  • Ouellet H., M. Gosselin et J.P. Artigau. 1990. Nomenclature française des oiseaux d'Amérique du Nord. Secrétariat d'État du Canada. 457 p.

  • Parker III, T. A., D. F. Stotz, and J. W. Fitzpatrick. 1996. Ecological and distributional databases for neotropical birds. The University of Chicago Press, Chicago.

  • Parks Canada. 2000. Vertebrate Species Database. Ecosystems Branch, 25 Eddy St., Hull, PQ, K1A 0M5.

  • Pendleton, B. A. G., B. A. Millsap, K. W. Cline, and D. M. Bird. 1987. Raptor management techniques manual. National Wildlife Federation, Sci. and Tech. Ser. No. 10. 420 pp.

  • Poole, A. F. and F. B. Gill. 1992. The birds of North America. The American Ornithologists' Union, Washington, D.C. and The Academy of Natural Sciences, Philadelphia, PA.

  • Randi, E., et al. 1991. Allozyme divergence and phylogenetic relationships within the Strigiformes. Condor 93:295-301.

  • Russell, R. W., et al. 1991. A visual study of migrating owls at Cape May Point, New Jersey. Condor 93:55-61.

  • Smith, D.G. 1987b. Owl census techniques. Pages 304-307 in R.W. Nero, R.J. Clark, R.J. Knapton, and R.H. Hamre, editors. Biology and conservation of northern forest owls. USDA Forest Service, Gen. Tech. Rep. RM-142.

  • Terres, J. K. 1980. The Audubon Society encyclopedia of North American birds. Alfred A. Knopf, New York.

  • Voous, K. H., and A. Cameron. 1989. Owls of the Northern Hemisphere. MIT Press, Cambridge, Massachusetts. 320 pp.

  • Walker, L.W. 1974. The book of owls. Alfred A. Knopf, Inc. New York. 255 pp.

  • Wildlife Management Information System (WMIS). 2006+. Geo-referenced wildlife datasets (1900 to present) from all projects conducted by Environment and Natural Resources, Government of the Northwest Territories, Canada.  Available at http://www.enr.gov.nt.ca/programs/wildlife-research/wildlife-management-information-services

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