Illinois Natural History Survey - University of Illinois

Boreal owl
Aegolius funereus

 

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: Aegolius
  • Species: Aegolius funereus
  • Authority: Linnaeus

Comments on taxonomy:
In late 1930's and prior was classified under scientific name Cryptoglaux funerea richardsoni, Richardson's owl *04*.

 


OCCURENCE IN ILLINOIS

Species occurs between mid October and early March in the north as a very rare winter vagrant *14*. Only 5 records; none of which are recent *14*.

 


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

State Status:

Endangered Threatened Proposed

Other:

Game Furbearer Nongame protected
Sportfish Commercial Pest None of the above

Comments on status:
Considered beneficial to man due to predation on rodent pests *04*. Protected by the Federal Migratory Bird Treaty Act of 1918 and the Illinois Wildlife Code of 1972 *13,15*.

 


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:

Cover typeStructural stageCanopy closureSeason
White-red-jack pine Young tree
(1-9" dia.)
Unknown Fall/winter

Associated tree species:

  • White pine

National wetland inventory classifications:

SystemSubsystemClassSubclassWater regime modifiersWater chemistry
Palustrine   Forest   Unknown/unspecified Unknown/unspecified

Comments on species-habitat associations:
Seems to prefer coniferous woodlands *12,14*.

Important plant and animal association: Common flickers; pileated woodpeckers; squirrel; raven; thrush.
Parasite: Herpesvirus strigis.
H. strigis causes a viral disease, not usually fatal *05*. Terrestrial associations: include common flickers, pileated woodpeckers, squirrel, raven, thrush *04,06,10*.

Species-habitat interrelations: No comments.

 


GUILDS

Feed-guilding: No records.

Comments on feed-guilding: No comments.

Breed-guilding: No records.

Comments on breed-guilding: No comments.

 


FOOD-HABITS

Trophic level is CARNIVORE

 

Food itemLife stage/plant part
Mammals Unknown
Soricidae (shrews) Unknown
Sciuridae (squirrels, chipmunks, marmots, prairie dogs) Unknown
Cricetidae (woodrats,mice,voles,lemmings,muskrat) Adult
Birds Unknown
Important:
Mammals Unknown
Cricetidae (woodrats,mice,voles,lemmings,muskrat) Adult
Juvenile:
Mammals Unknown
Cricetidae (woodrats,mice,voles,lemmings,muskrat) Adult
Adult:
Mammals Unknown
Soricidae (shrews) Unknown
Sciuridae (squirrels, chipmunks, marmots, prairie dogs) Unknown
Cricetidae (woodrats,mice,voles,lemmings,muskrat) Adult
Birds Unknown

 

Comments on food habits: 
General: No comments.
Juvenile: Fed prey hunted by parents *06*.
Adult: No comments.


ENVIRONMENTAL ASSOCIATIONS

General:

  • Aquatic habitats: marsh
  • Tree cavities: cavities in live trees
  • Tree cavities: cavities in dead/dying trees
  • Ecotones: woodland/crop fields
  • Ecotones: woodland/old fields
  • Ecotones: woodland/water
  • Ecotones: woodland/grassland
  • Ecotones: coniferous trees/deciduous trees
  • Meadows: see comments
  • Old fields: see comments
  • Coniferous forest: see comments
  • Hardwood forest: see comments
  • Vegetation successional stage: stable prairie/grassland
  • Unknown

Limiting:

  • Tree cavities: cavities in live trees
  • Tree cavities: cavities in dead/dying trees

Egg

  • Unknown

Feeding adult:

  • Aquatic habitats: marsh
  • Ecotones: woodland/crop fields
  • Ecotones: woodland/old fields
  • Ecotones: woodland/water
  • Ecotones: woodland/grassland
  • Meadows: see comments
  • Old fields: see comments
  • Vegetation successional stage: stable prairie/grassland

Resting adult:

  • Ecotones: woodland/crop fields
  • Ecotones: woodland/old fields
  • Ecotones: woodland/water
  • Ecotones: woodland/grassland
  • Ecotones: coniferous trees/deciduous trees
  • Coniferous forest: see comments

Breeding adult:

  • Tree cavities: cavities in live trees
  • Tree cavities: cavities in dead/dying trees
  • Ecotones: coniferous trees/deciduous trees
  • Hardwood forest: see comments

Comments on environmental associations:
General: No comments.
Feeding adult: Foraging sites include marshes, grasslands, and old fields adjacent to woodlots *04,07,12*.
Resting adult: See [LH]
Breeding adult: Nesting takes place in mixed coniferous and deciduous woodlots in live or dead tree cavities, usually in dense woods *04,06,10*.


LIFE HISTORY

Origin: Native *14*.

Reproduction: Breeding season = mid-April to early June (in southern) male flies in circle above tree in which prospective female is perched *04*; clutch size = 3-7, average = 5 *04*.

Behavior: Strict nocturnal habits *04,12,13*; foraging strategy/ sites = marshes, grasslands, and old fields adjacent to woodlots where nesting or roosting occurs, known to thaw frozen prey by warming it in much the same way eggs are incubated *04,07,12*; nest site = mixed coniferous and deciduous woodlots in live or dead tree cavities left by common flickers or pileated woodpeckers, and sometimes squirrel raven or thrush nests, usually in dense woods *04,06,10*; development of young = see reference *10*; parental care of young = male provide virtually all food for brooding female and young *06*.

Population parameters: Population fluctuates with regard to the 3-4 year cycle associated with microtine populations *08*.

 


MANAGEMENT PRACTICES

Beneficial:

  • Maintaining habitat diversity
  • Maintaining unique or special habitat features (wetlands, snags, caves, cliffs, talises, etc.
  • Deferred cutting of forest areas
  • Maintaining forests

Comments on management practices:
Species protected by the Illinois Wildlife Code Of 1972 and the Federal Migratory Bird Treaty Act of 1918 *13,15*.

 


REFERENCES

0. UNVERIFIED

1. FOSTER, C. 101 CHEATHAM HALL, BLACKSBURG, VA. 24061.

2. FLANAGAN, J. 1107 PROGRESS, APT. 2, BLACKSBURG, VA. 24060.

3. ORNITHOLOGY, VIRGINIA SOCIETY OF, 1979. VIRGINIA'S BIRDLIFE: AN ANNOTATED CHECK-LIST. VIRGINIA SOCIETY OF ORNITHOLOGY, LYNCHBURG, VA.

4. BENT, A.C. 1938. LIFE HISTORIES OF NORTH AMERICAN BIRDS OF PREY. PART 2. BULL. 170. U.S. NATL. MUS., WASHINGTON, D.C. NUMBER OF PAGES: 482 SOURCE FORM: PAPER.

5. BURTSCHER, H., AND M. SIBALIN. 1975. HERPESVIRUS STRIGIS: HOST SPECTRUM AND DISTRIBUTION IN INFECTED OWLS. J. WILDL. DIS. 11:164-169.

6. ECKERT, K.R. AND T.L. SAVALOJA. 1979. FIRST DOCUMENTED NESTING OF BOREAL OWL SOUTH OF CANADA. AM. BIRDS 33:135-137.

7. BONDRUP-NIELSEN, S. 1977. THAWING OF FROZEN PREY BY BOREAL AND SAW-WHET OWL. PAGES 595-601. CAN. J. ZOOL. VOL. 55. SOURCE FORM: PAPER.

8. HORNFELDT, B. 1978. SYNCHRONOUS POPULATION FLUCTUATIONS IN VOLES, SMALL GAME, OWLS, AND TULAREMIA IN NORTHERN SWEDEN. PAGES 141-152. OECOLOGIA. VOL. 32 SOURCE FORM: PAPER.

9. EARHART, C.M., AND N.K. JOHNSON. 1970. SIZE DIMORPHISM AND FOOD HABITS OF NORTH AMERICAN OWLS. PAGES 251-264 CONDOR. VOL. 72. SOURCE FORM: PAPER.

10. BONDRUP-NEILSEN, S. 1976. FIRST BOREAL OWL NEST FOR ONTARIO, WITH NOTES ON DEVELOPMENT OF YOUNG. CAN. FIELD-NAT. 90:477-479.

11. ROBBINS, C.S., B. BRUUN, AND H.S. ZIM. 1966. BIRDS OF NORTH AMERICA: A GUIDE TO FIELD IDENTIFICATION. GOLDEN PRESS, NEW YORK, N.Y.

12. CATLING, P.M. 1972. A STUDY OF THE BOREAL OWL IN SOUTHERN ONTARIO WITH PARTICULAR REFERENCE TO THE IRRUPTION OF 1968-1969. PAGES 223-232 CAN. FIELD-NAT. VOL. 86. SOURCE FORM: PAPER.

13. UNKNOWN. 1982. FISH AND WILDLIFE. 50 CFR 10 (CODE OF FEDERAL REGULATIONS). GENERAL SERV. ADMIN., WASHINGTON, D.C. NUMBER OF PAGES: 7 SOURCE FORM: OTHER 3.

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

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

 


 

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