Great Gray Owl (Strix Nebulosa) R

Great Gray Owl (Strix nebulosa) R. Gregory Corace III, Ph.D.

Sugar Island, Chippewa Co., MI © John Van Orman (Click to view a comparison of Atlas I to II)

Perhaps no other member of the bird (Wood 1951, Master 1979, Jensen et al. 1982). However, MBBA I resulted in no Confirmed community of Michigan instills the sense of the survey blocks. Instead, five Probable blocks North Woods more than the Great Gray Owl. were in three UP counties: Chippewa, Mackinac Characterized by its large size, dappled gray (Bois Blanc Island), and Gogebic. Three plumage, prominent facial disks, and secretive Possible blocks were in Chippewa Co., nature, this species has long fascinated many including Neebish Island (Evers 1991). birders and other naturalists (Nero 1980).

However, with a primary breeding range that Relative to MBBA I, MBBA II produced a encompasses boreal regions throughout the slight increase in the percentage of blocks and Northern Hemisphere, the Great Gray Owl is townships with records. Most of these records only a regular breeder among the northern tier were from the eastern UP counties of Alger, of states of the conterminous U. S. and within Schoolcraft, Luce, and Chippewa, with one several associated western mountain ranges Possible block in northern Emmet Co. of the (Bull and Duncan 1993). In the Upper Great NLP. In 2004 the first confirmed breeding Lakes region, scattered confirmed breeding record for this species in Michigan came from records exist for Minnesota (Janssen 1987), the U. S. Fish and Wildlife Service at Seney Wisconsin (Merkel 1989, Cutright et al. 2006), National Wildlife Refuge (NWR) in Schoolcraft and now Michigan (Baetsen et al. 2005), while Co. (Baetsen et al. 2005), with an adjacent block substantially more records exist for northern later having another confirmed record. Ontario (Johnson 1987).

During invasion years, the dedicated birder has Distribution a fair chance of observing wintering birds in the Although Barrows (1912) was skeptical eastern UP. Neebish Island offers one of the regarding any assertions that the Great Gray best spots to observe birds, but one should not Owl bred in Michigan, sporadic breeding-season discount the agricultural lands in Chippewa and observations of adult birds and their young have Mackinac counties either, especially around occurred over the intervening decades. Most Rudyard, Pickford, and Sault Ste. Marie. As observations have come from the eastern UP, past records from MBBA I and MBBA II especially Neebish Island of Chippewa Co.

© 2010 Kalamazoo Nature Center Great Gray Owl (Strix nebulosa) R. Gregory Corace III, Ph.D. indicate, observing breeding birds is much more general and Seney NWR in particular. The fact difficult. Any observation of breeding birds that seemingly suitable nest sites exist in much should be reported to MNFI and MAS. of the eastern UP lend some support, albeit weakly, to the contention that more breeding Breeding Biology Great Gray Owls may be found in the area. Although little is known about the breeding biology of the Great Gray Owl in the Upper The diet of the Great Gray Owl consists Great Lakes region relative to populations found primarily of small rodents, with voles of elsewhere, some geographic variation in considerable importance during both the breeding biology and habitat selection does exist breeding and wintering seasons (Bull and (Bull and Duncan 1993). Baetsen et al. (2005) Duncan 1993). At Seney NWR, skeletal provided a detailed chronology of nesting remains from 30 individual prey items were behavior for the breeding pair at Seney NWR. identified from regurgitated pellets collected First observations of adult birds at the nest were during the breeding season (Corace et al. 2006). made on 30 April 2004. The initial observation Mammals comprised 87% of the prey items. of owlets was on 19 May, with the older of the Those prey species identified included meadow two owlets fledged by 4 June and the younger vole, star-nosed mole, unknown vole species, by 11 June. southern bog lemming, and northern flying squirrel. In particular, star-nosed mole Characteristics of the nest site at Seney NWR comprised a surprisingly large percentage (23%) were quantified at two spatial scales by Corace of the identified remains, suggesting that the et al. (2006). The adult birds nested in a mosaic adults spent a considerable period of time of forested and non-forested cover types, similar foraging over non-forested habitats. Previous in nature to occupied breeding habitat in research (Master 1979) in the eastern UP adjacent Wisconsin (Merkel 1989) and Ontario indicated that the diet of wintering birds was (Johnson 1987). The stick nest was located in a primarily comprised of voles. large-toothed aspen that was located within a Society of American Foresters Red Pine Abundance and Population Trends Research Natural Area dominated by red pine No quantitative data exist for tracking the and white pine. Within 50 m (164 ft) of the nest abundance or population trend of this species in little variation in measured habitat features Michigan. Evers (1991) and Baetsen et al. existed. Overall, the forest stand had multiple (2005) provided thorough documentations of the cohorts of relatively large trees (mean diameter winter “invasion years”, or those years in which at breast height was 44 cm or 17 in). The forest a large number of birds can be found wintering understory was relatively open, and consisted in the more northern parts of this state due to primarily of Vaccinium spp. Within a 2-km cyclically reduced populations of rodent prey in (1.24-mi) buffer of the nest, a total of 29 land Canada (Bull and Duncan 1993). During the cover types were found based on an analysis of MBBA II sampling period, there seemed to be digitized aerial imagery. Forest types only one winter (2004-05) in which a large dominated the buffer, but average patch size for number of birds was observed, mostly in all land cover types was relatively small (<12 ha Chippewa County (Murphy 2003, 2004, 2005, or <30 ac), indicating a high degree of 2006, Wuepper 2008). heterogeneity in the buffer. Ultimately, Corace et al. (2006) came to the conclusion that In other parts of the breeding range of the relatively little was unique to the nest site species, increased surveying efforts have relative to many parts of the eastern UP in yielded more breeding records (Follen 1987,

Gostomski 1997). The same may hold true in Gostomski, T.J. 1997. Observations of Great Michigan— and the eastern UP in particular—if Gray Owls (Strix nebulosa) within the efforts at surveying for this and other owl Apostle Islands National Lakeshore and species were increased. surrounding area, Bayfield and Ashland Counties. Passenger Pigeon 59:275–277. Conservation Needs Janssen, R.B. 1987. Birds in Minnesota. No specific conservation-related management Minneapolis, University of Minnesota Press. efforts are needed or planned. However, for this Jensen, W.F., W.L. Robinson, and N.L. and many other bird species, maintaining the Heitman. 1982. Breeding of the Great Gray present assemblage of habitats and the Owl on Neebish Island, Michigan. The Jack- undeveloped nature of the UP is likely vital for Pine Warbler 60:27–28. their long-term conservation in Michigan. Johnson, M. 1987. Great Gray Owl. In Cadman, M.D., P.F.J. Eagles, and F.M. Helleiner (eds). Atlas of the Breeding Birds of Literature Cited Ontario. Waterloo, University of Waterloo Press. Baetsen, R., B. Heuvelhorst, and T. Casselman. Master, L.L. 1979. Some observations on Great 2005. Nesting of the Great Gray Owl, Seney Gray Owls and their prey in Michigan. The National Wildlife Refuge, Schoolcraft Jack-Pine Warbler 57:215–217. County, Michigan. Michigan Birds and Merkel, K.J. 1989. Wisconsin’s first Natural History 12:2–5. documented nesting of Great Gray Owls. Barrows, W. B. 1912. Michigan Bird Life. East Passenger Pigeon 51:133–143. Lansing, Michigan Agricultural College Murphy, B. 2003. Michigan Bird Survey: Special Bulletin. Winter 2002-2003 (Dec.-Feb.). Michigan Bull, E.L., and J.R. Duncan. 1993. Great Gray Birds and Natural History 10:105–126. Owl (Strix nebulosa). In The Birds of North Murphy, B. 2004. Michigan Bird Survey: America, No. 41 (A. Poole and F. Gill, Winter 2003-2004 (December-February). Eds.). The Academy of Natural Sciences, Michigan Birds and Natural History Philadelphia and The American 11:130–145. Ornithologists’ Union, Washington, D. C. Murphy, B. 2005. Michigan Bird Survey: Corace, R.G., III, B. Lundrigan, and P. Myers. Winter 2004-2005 (December-February). 2006. Nest site habitat and prey use of a Michigan Birds and Natural History breeding pair of Great Gray Owls in the 12:145–163. Upper Peninsula of Michigan. Passenger Murphy, B. 2006. Michigan Bird Survey: Pigeon 68:353-360. Winter 2004-2005 (December-February). Cutright, N.J., B.R. Harriman, and R.W. Howe. Michigan Birds and Natural History 2006. Atlas of the Breeding Birds of 13:123–143. Wisconsin. Waukesha, Wisconsin Society Nero, R.W. 1980. The Great Gray Owl: for Ornithology. phantom of the northern forest. Washington, Evers, D.C. 1991. Great Gray Owl (Strix D.C., Smithsonian Institution Press. nebulosa). In Brewer, R.A., G.A. McPeek, Wood, N.A. 1951. The Birds of Michigan. Ann and R.A. Adams, Jr. (eds). The Atlas of Arbor, University of Michigan Press. Breeding Birds of Michigan. East Lansing, Wuepper, J.T. 2008. Michigan Bird Survey: Michigan State University Press. Winter 2007-2008 (December-February). Follen, D.G., Sr. 1987. Wisconsin Great Gray Michigan Birds and Natural History Owl update. Passenger Pigeon 49:96–98. 15:100–123.

Suggested Citation

Corace, R.G. 2010. Great Gray Owl (Strix nebulosa). In Chartier, A.T., J.J. Baldy, and J.M. Brenneman (eds.). 2010. The Second Michigan Breeding Bird Atlas. Kalamazoo Nature Center. Kalamazoo, MI. Accessed online at: .