Illinois Natural History Survey - University of Illinois

Long-eared Owl
Asio otus

 

Taxonomy
Occurence in Illinois
Status
Habitat associations
Guilds
Food-habits
Environmental associations
Life history
Management practices
References


TAXONOMY

 

  • Phylum: Chordata
  • Class: Aves
  • Order: Strigiformes
  • Family: Strigidae
  • Genus: Asio
  • Species: Asio otus
  • Authority: Linnaeus

OCCURENCE IN ILLINOIS

Late Nov.- early April; uncommon winter resident in north and central. Rare winter resident in south. Rare summer resident*01*.

 


STATUS

Items in bold indicate applicable categories
Forest Service Categories: S = recommended for regional sensitive status, F = forest listed species, M = management indicator species

Federal Status:

Endangered Threatened Proposed for listing
Candidate for proposal Recovery plan approved Recovery plan received (USFWS)
Recovery plan in preparation Under notice of review Delisted
Migratory EPA indicator Forest Serv.- Shawnee species (F)

State Status:

Endangered Threatened Proposed

Other:

Game Furbearer Nongame protected
Sportfish Commercial Pest None of the above

Comments on status:
Because of low population levels and possible lack of forage and nesting habitat is protected by Illinois Endangered Species Act, 1972 *02*. Also protected by the Migratory Bird Treaty Act 1918 *16* and the Illinois Wildlife Code, 1971 *17*.

 


HABITAT ASSOCIATIONS

Items in bold indicate applicable categories

General habitat:

Unknown Terrestrial Aquatic Riparian

USFS timber inventory forest size class:

Unknown Unstocked Seedling Sapling
Seedling/sapling Pole Mature Over mature

Land use and land cover:

Unknown   Urban Residential
Commercial
Industrial
Transportation, communication
Complex industrial/commercial
Mixed
Other
Agricultural Crop, pasture
Orchards, groves, nurseries
Feedlot
Other
Rangeland Herbaceous
Shrub and brush
Mixed
Forestland Deciduous
Evergreen
Mixed
Water Stream
Lake
Reservoir
Bay
Wetland Forest
Non-forest
Barren Salt flat
Beach
Sand
Rock
Mine
Transit
Mix

 


Forest cover types: No records

Associated tree species: No records

Comments on species-habitat associations:
No comments

Important plant and animal association: In two IL studies (and in many from other states) Microtus species were the most common prey *9,14*. In another IL study, Peromyscus species comprised over half of prey *15*.

High value habitats

HabitatStructural stageSeason
Cropland and pasture Not applicable
(HVAL-HAB cover)
All
Evergreen forest land Unknown All
Upland forest Unknown All
Agricultural field Not applicable
(HVAL-HAB cover)
All
Orchards, nurseries, arboretums, etc. Not applicable
(HVAL-HAB cover)
All

Species-habitat interrelations: IL populations are generally migrants *02*. High value habitats,then, are those for roosting: stands of evergreen trees (pines, junipers) *09,15* and hunting: open areas (pastures, grassy areas, forest edges) *03,09* from late Nov. to early Apr.*01*. Rare summer resident*01*, high value habitat during breeding season includes those mentioned above and abandoned nests of large birds and squirrels for nesting *03,05,08*.

 


GUILDS

Feed-guilding:

HabitatStructural stageSeasonFeed-guilds
Cropland and pasture Not applicable
(HVAL-HAB cover)
All Shrub strata- birds
Terrestrial surface- small mammals (<1 kg)
Terrestrial surface- arthropods
Terrestrial surface- amphibians
Terrestrial surface- reptiles
Terrestrial surface- birds
Upland forest Unknown All Shrub strata- birds
Terrestrial surface- small mammals (<1 kg)
Terrestrial surface- arthropods
Terrestrial surface- amphibians
Terrestrial surface- reptiles
Terrestrial surface- birds
Agricultural field Not applicable
(HVAL-HAB cover)
All Shrub strata- birds
Terrestrial surface- small mammals (<1 kg)
Terrestrial surface- arthropods
Terrestrial surface- amphibians
Terrestrial surface- reptiles
Terrestrial surface- birds
Orchards, nurseries, arboretums, etc. Not applicable
(HVAL-HAB cover)
All Shrub strata- birds
Terrestrial surface- small mammals (<1 kg)
Terrestrial surface- arthropods
Terrestrial surface- amphibians
Terrestrial surface- reptiles
Terrestrial surface- birds

Comments on feed-guilding:
Microtus spp. and Peromyscus spp. are most common and important prey *09,14,15*. Predatory, hunting over open areas and forest edges *03,09*.

Breed-guilding:

HabitatStructural stageSeasonBreed-Guilds
Deciduous forest land Unknown Spring/summer Tree canopy, small branches of live broad-leaved deciduous trees
Tree canopy, small branches of live needle-leaved deciduous trees
Tree canopy, small branches of live broad-leaved evergreen trees
Tree canopy, small branches of live needle-leaved evergreen trees
Tree canopy, large branches of live broad-leaved deciduous trees
Tree canopy, large branches of live needle-leaved deciduous trees
Tree canopy, large branches of live broad-leaved evergreen trees
Tree canopy, large branches of live needle-leaved evergreen trees
Tree canopy, large branches of dead broad-leaved deciduous trees
Tree canopy, large branches of dead needle-leaved deciduous trees
Tree canopy, large branches of dead broad-leaved evergreen trees
Tree canopy, large branches of dead needle-leaved evergreen trees
Evergreen forest land Unknown Spring/summer Tree canopy, small branches of live broad-leaved deciduous trees
Tree canopy, small branches of live needle-leaved deciduous trees
Tree canopy, small branches of live broad-leaved evergreen trees
Tree canopy, small branches of live needle-leaved evergreen trees
Tree canopy, large branches of live broad-leaved deciduous trees
Tree canopy, large branches of live needle-leaved deciduous trees
Tree canopy, large branches of live broad-leaved evergreen trees
Tree canopy, large branches of live needle-leaved evergreen trees
Tree canopy, large branches of dead broad-leaved deciduous trees
Tree canopy, large branches of dead needle-leaved deciduous trees
Tree canopy, large branches of dead broad-leaved evergreen trees
Tree canopy, large branches of dead needle-leaved evergreen trees
Mixed forest land Unknown Spring/summer Tree canopy, small branches of live broad-leaved deciduous trees
Tree canopy, small branches of live needle-leaved deciduous trees
Tree canopy, small branches of live broad-leaved evergreen trees
Tree canopy, small branches of live needle-leaved evergreen trees
Tree canopy, large branches of live broad-leaved deciduous trees
Tree canopy, large branches of live needle-leaved deciduous trees
Tree canopy, large branches of live broad-leaved evergreen trees
Tree canopy, large branches of live needle-leaved evergreen trees
Tree canopy, large branches of dead broad-leaved deciduous trees
Tree canopy, large branches of dead needle-leaved deciduous trees
Tree canopy, large branches of dead broad-leaved evergreen trees
Tree canopy, large branches of dead needle-leaved evergreen trees
Upland forest Unknown Spring/summer Tree canopy, small branches of live broad-leaved deciduous trees
Tree canopy, small branches of live needle-leaved deciduous trees
Tree canopy, small branches of live broad-leaved evergreen trees
Tree canopy, small branches of live needle-leaved evergreen trees
Tree canopy, large branches of live broad-leaved deciduous trees
Tree canopy, large branches of live needle-leaved deciduous trees
Tree canopy, large branches of live broad-leaved evergreen trees
Tree canopy, large branches of live needle-leaved evergreen trees
Tree canopy, large branches of dead broad-leaved deciduous trees
Tree canopy, large branches of dead needle-leaved deciduous trees
Tree canopy, large branches of dead broad-leaved evergreen trees
Tree canopy, large branches of dead needle-leaved evergreen trees
Orchards, nurseries, arboretums, etc. Unknown Spring/summer Tree canopy, small branches of live broad-leaved deciduous trees
Tree canopy, small branches of live needle-leaved deciduous trees
Tree canopy, small branches of live broad-leaved evergreen trees
Tree canopy, small branches of live needle-leaved evergreen trees
Tree canopy, large branches of live broad-leaved deciduous trees
Tree canopy, large branches of live needle-leaved deciduous trees
Tree canopy, large branches of live broad-leaved evergreen trees
Tree canopy, large branches of live needle-leaved evergreen trees
Tree canopy, large branches of dead broad-leaved deciduous trees
Tree canopy, large branches of dead needle-leaved deciduous trees
Tree canopy, large branches of dead broad-leaved evergreen trees
Tree canopy, large branches of dead needle-leaved evergreen trees

Comments on breed-guilding:
Structural stage of trees used for nesting unknown but long-eared uses abandoned bird or squirrel nests (10-40 ft. high), suggesting large trees *03,08,09*.

 


FOOD-HABITS

Trophic level is CARNIVORE

Food itemLife stage/plant part
Arthropoda Adult
Amphibians Adult
Reptiles Adult
Mammals Adult
Soricidae (shrews) Adult
Chiroptera (bats) Adult
Leporidae (rabbits, hares) Adult
Sciuridae (Squirrels, chipmunks, marmots, prairie dogs) Adult
Geomyidae (pocket gophers) Adult
Cricetidae (woodrats, mice, voles, lemmings, muskrats) Adult
Muridae (Norway rat, house mouse) Adult
Birds Adult
Passeriformes Adult
Important:
Mammals Adult
Cricetidae (woodrats, mice, voles, lemmings, muskrats) Adult
Muridae (Norway rat, house mouse) Adult
Juvenile:
Amphibians Adult
Reptiles Adult
Mammals Adult
Soricidae (shrews) Adult
Chiroptera (bats) Adult
Leporidae (rabbits, hares) Adult
Sciuridae (Squirrels, chipmunks, marmots, prairie dogs) Adult
Geomyidae (pocket gophers) Adult
Cricetidae (woodrats, mice, voles, lemmings, muskrats) Adult
Muridae (Norway rat, house mouse) Adult
Birds Adult
Passeriformes Adult
Adult:
Amphibians Adult
Reptiles Adult
Mammals Adult
Soricidae (shrews) Adult
Chiroptera (bats) Adult
Leporidae (rabbits, hares) Adult
Sciuridae (Squirrels, chipmunks, marmots, prairie dogs) Adult
Geomyidae (pocket gophers) Adult
Cricetidae (woodrats, mice, voles, lemmings, muskrats) Adult
Muridae (Norway rat, house mouse) Adult
Birds Adult
Passeriformes Adult

Comments on food habits: 
General: Microtus spp. most often cited as most abundant prey *14*. Peromyscus spp. and Mus musculus (house mouse) are also common prey *09,14,15*.
Juvenile: Juveniles are fed pieces of prey (see comments on general and important food habits) until old enough to receive whole carcasses *07*
Adult: See general food habits [FH].


ENVIRONMENTAL ASSOCIATIONS

General:

  • Ecotones: woodland/crop fields
  • Ecotones: woodland/old fields
  • Ecotones: woodland/grassland
  • Ecotones: coniferous trees/deciduous trees
  • Pastures: see comments
  • Grassland: see comments
  • Meadows: see comments
  • Old fields: see comments
  • Coniferous forest: see comments
  • Hardwood forest: see comments
  • Vegetation successional stage: see comments
  • Unknown

Limiting:

  • Coniferous forest: see comments
  • Hardwood forest: see comments

Egg

  • Unknown

Feeding juvenile:

  • Coniferous forest: see comments
  • Hardwood forest: see comments

Resting juvenile:

  • Coniferous forest: see comments
  • Hardwood forest: see comments

Feeding adult:

  • Ecotones: woodland/crop fields
  • Ecotones: woodland/old fields
  • Ecotones: woodland/grassland
  • Ecotones: coniferous trees/deciduous trees
  • Pastures: see comments
  • Grassland: see comments
  • Meadows: see comments
  • Old fields: see comments
  • Vegetation successional stage: see comments

Resting adult:

  • Coniferous forest: see comments
  • Hardwood forest: see comments

Breeding adult:

  • Coniferous forest: see comments
  • Hardwood forest: see comments

Comments on environmental associations:
General: Long-eared owls are found in light broad-leaved & coniferous forests, riverine forests, and parks. Known to roost in dense cover, often pines *05*. Hunting occurs over open country *05*.
Feeding juvenile: Assume adopts feeding habits of adult.
Resting juvenile: Assume adopts roosting habits of adult.
Feeding adult: Hunts over open grassy places and along forest edges *05*.
Resting adult: Known to roost in pines and pine plantations in winter *02*. Roosts in dense cover.
Breeding adult: Breeds in abandoned nests of other birds, particularly those of corvid and small diurnal birds of prey *05*. Coniferous of deciduous forests *02*. May also nest in squirrel nest or hollow trees *02*.


LIFE HISTORY

Origin: Native *01,02*.

Physical description: Brown to gray (much color variation even within a population), long ear tufts, breast streaked lengthwise, slim bodied. length 13-16 in., wingspread 36-42 in.*04,05*. ave. weight, males 245 gm., females 280 gm *06*.

Reproduction: Courtship begins perhaps as early as Feb., about 2 wks. before egg laying *03,07*. Competitive calling and performances and also non-competitive calling generally precede nest selection and copulation; this pattern is variable *07*. The nest is an abandoned nest of crows, other large birds, or squirrels about 10-40 ft. high *03,07,08*. Nesting season ranges (in WY) .1 To .4 sq. mi.*11*. 2-10 eggs, 4-5 ave. *03,07*; 8-10 in yrs. of peak vole populations *05*. A second brood may be raised in good yrs. Incubation begins with first egg laid, lasts about 23-26 days *03,05,07*. Female incubates, male hunts and provides for female *05,07*. Both sexes defend young *03*. Young leave nest at 23-26 days, begin to fly at about 34 days *03*. Blind at hatching, eyes open in a few days; covered with down which is replaced by juvenile plumage in a few weeks *08*.

Behavior: Almost completely nocturnal *03,05,08*, roosts in pine groves in il. *01,09*, In groups of 2-12 owls *09*. Will "stretch" body and freeze, resembling a tree branch *05,08,10*. In WY, 3 nesting season ranges were .1 To .4 sq. mi. each. Individuals did not hunt within nesting ranges of other pairs *11*. Hunts over open areas: meadows, forest edges *03,05*. IL Populations are mostly migrants from northern areas; summer records are rare *01*. In mi., young may stay through next breeding season *07*.

Limiting factors: Snakes may prey upon nesting *12*. Man may be responsible for most critical limitations: loss of habitat, reduction of prey populations and shooting *02,08*.

Population parameters: Breeding populations are extremely low: lack of habitat, use of rodenticides may be contributing factors *02*. One banded long-eared in Germany lived 27 yrs *03*. Other population parameter information not available.

 


MANAGEMENT PRACTICES

Beneficial:

  • Maintaining undisturbed/undeveloped areas
  • Maintaining natural ecological succession
  • Developing/maintaining edge (ecotones)
  • Performing special survey prior to prescription
  • Controlling land use and human activities
  • Practices other than those included on the ifwis list (see comments)
  • Grazing management to allow vegetative recovery
  • Developing/maintaining hedge rows/windbreaks
  • Segregating and amending soil (topsoil, subsoil, and/or soil substitute) in mine areas
  • Protecting topsoil until permanent vegetation can be established in mine areas
  • Site preparation for revegetation of mined land- establishing commercial forest
  • Site preparation for revegetation of mined land- establishing noncommercial forest
  • Site preparation for revegetation of mined land- establishing woody wildlife area
  • Developing/maintaining native vegetation
  • Mowing forest openings after August 1

Adverse:

  • Haying/mowing
  • Applying pesticide on agricultural land
  • Uncontrolled grazing by domestic livestock
  • Strip mining
  • Applying pesticides
  • Mowing
  • Cutting and deforestation

Comments on management practices:
See "species-habitat interrelations" and "life history" limiting factors. Habitat preservation and protection from disturbance are important *02*.

 


REFERENCES

0. BUTCHER, M. K. ILLINOIS NAT. HIST. SURV. 607 E. PEABODY DR., CHAMPAIGN, IL. (217) 333-6846.

1. BOHLEN, H. 1978. AN ANNOTATED CHECK-LIST OF THE BIRDS OF ILLINOIS. ILLINOIS STATE MUS. POP. SCI. SER., VOL. IX. 156 P.

2. BOWLES, M. L., V. E. DIERSING, J. E. EBINGER AND H. C. SCHULTZ, EDS. 1981. ENDANGERED AND THREATENED VERTEBRATE ANIMALS AND VASCULAR PLANTS OF ILLINOIS. ILLINOIS DEPT. CONSERV. 189 P.

3. TERRES,J. 1980. AUDUBON SOCIETY: ENCYCLOPEDIA OF NORTH AMERICAN BIRDS. ALFRED KNOPF, NEW YORK. 1109 P.

4. PETERSON, R. 1980. A FIELD GUIDE TO THE BIRDS. 4 ED. HOUGHTON-MIFFLIN CO., BOSTON. 384 P.

5. BURTON, J. A., ED 1973. OWLS OF THE WORLD. E. P. DUTTON AND CO.,INC., NEW YORK. 216 P.

6. EARHART, C. M. AND N. K. JOHNSON. 1970. SIZE DIMORPHISM AND FOOD HABITS OF NORTH AMERICAN OWLS. CONDOR 72 (3): 257-264.

7. ARMSTRONG, W.H. 1958. NESTING AND FOOD HABITS OF THE LONG-EARED OWL IN MICHIGAN. MICH. STATE UNIV. MUS. PUBL. 1(2):61-96.

8. BENT, A. C. 1938. LIFE HISTORIES OF NORTH AMERICAN BIRDS OF PREY (PART 2) U. S. NATL. MUS. BULL. NO. 170.

9. GRABER, R. R. 1962. FOOD AND OXYGEN CONSUMPTION IN THREE SPECIES OF OWLS (STRIGIDAE). CONDOR 64 (6): 473-487.

10. HAUSMAN, L.A. 1948. BIRDS OF PREY OF NORTHEASTERN NORTH AMERICA. RUTGERS UNIV. PRESS, NEW BRUNSWICK. 164 P.

11. CRAIGHEAD, J.J. AND F.C. CRAIGHEAD, JR. 1956. HAWKS, OWLS, AND WILDLIFE. THE STACKPOLE CO., HARRISBURG, PA. 443 PP.

12. AMSTRUP, S.C. AND T.P. MCENEANEY. 1980. BULL SNAKE KILLS AND ATTEMPTS TO EAT LONG-EARED OWL NESTLINGS. WILSON BULL. 92(3):402.

13. AMERICAN ORNITHOLOGISTS' UNION. 1982. THIRTY-FOURTH SUPPLEMENT TO THE AMERICAN ORNITHOLOGISTS' UNION. CHECK-LIST OF NORTH AMERICAN BIRDS. SUPPLEMENT AUK 99(3).

14. MARTI, C.D. 1976. A REVIEW OF PREY SELECTION BY THE LONG-EARED OWL. CONDOR 78(3): 331-336.

15. CAHN, A.R. 1930. ON THE FOOD OF CERTAIN OWLS IN EAST-CENTRAL ILLINOIS. AUK 47: 323-328.

16. U.S. FISH AND WILDLIFE SERVICE. 1983. CODE OF FEDERAL REGULATIONS. TI- TLE 50. WILDLIFE AND FISHERIES. CHAP 1. PP. 11-18. 50CFR1013. LIST OF MIGRATORY BIRDS. SPECIAL PUBL. FEDERAL REGISTER. GENERAL SERVICES ADMIN. OCTOBER 1.

17. ILLINOIS DEPARTMENT OF CONSERVATION. 1980. CONSERVATION LAWS. CH. 61. WILDLIFE. ART II 1. PAR 2.2. REPRINTED FROM ILLINOIS REVISED STATUTES, 1979. WEST PUBL. CO., ST. PAUL, MN. 120 P.

 


 

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